Final Exam Study Guide
Final Exam Study Guide 103
Popular in Life 103- Biology of Organisms
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This 65 page Study Guide was uploaded by email@example.com Notetaker on Sunday May 8, 2016. The Study Guide belongs to 103 at Colorado State University taught by Tanya Dewey in Winter 2016. Since its upload, it has received 109 views. For similar materials see Life 103- Biology of Organisms in Biology at Colorado State University.
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Chapter 26 Adaptation- trait evolves by selection for a particular function from an ancestor that didn’t have the trait. Different populations have different solutions to the same problem Phylogeny- the evolutionary relationships of a group of organisms The phylogeny tree is a diagram of ancestral relationships that describe patterns and tell when large events may have occurred Scientific names are binomial. The first part is the genus and the second part is the specific epithet. Both parts are required for naming the species Branch point- divergence of 2 species Sister taxa- groups that share a common ancestor Polytomy- more than 2 groups emerge Rooted- last common ancestor of all taxa Monophyletic group- 1 phylogenic group Paraphyletic group- excludes something from a tree Polyphyletic group- include something from a different group The tree of life suggest that animals and fungi are more closely related. The tree is also largely based on RNA genes, because these have evolved slowly. Ecology study of distribution and interactions of organisms with other organisms and the environment Organismal ecology study of an organism and its environment. Include behavioral ecology that studies responses to stimuli and group interactions and foraging patterns Evolutionary ecology adaptations to the environment. Events in ecological time influence evolutionary time processes. Population group of species living in same area Community group of interacting population of different species in an area Ecosystem community and abiotic environment. Energy flows, and chemicals cycle Chapter 27 Concepts What structural and functional adaption set prokaryotes up for success? -Cell wall maintains shape, protects the cell, and prevents bursting in a hypotonic environment -What makes prokaryotes cell walls different than eukaryote’s cell walls? *eukaryotes (such as plants and fungi) are made up of cellulose or chitin *bacteria cell walls have peptidoglycan a polymer of sugars linked by polypeptides Purpose of peptidoglycan? Encloses bacterium and anchors other molecules that extend from the surface The Gram stain uses crystal violet dye and iodine to determine the structure of a bacterium’s cell wall -Gram positive simple; cell wall on outside -Gram negative complex; outer and inner membrane sandwich the cell wall Miscellaneous structures Capsule- layer of polysaccharide or protein that surrounds the cell wall of most prokaryotes Endospores- when bacteria lack nutrients, they develop an endospore that are resistant to harsh conditions Fimbriae- hairlike appendages that allow prokaryotes to stick to their substrates Pili- appendages that pull 2 cells together to allow DNA transfer from one cell to the other Motility Taxis- directed movement toward or away from a stimulus. ½ of prokaryotes are capable of this Chemotaxis- directed movement toward or away from chemicals Flagella- most common form of movement. -can be dispersed across surface or concentrated at one end. -structure of flagella of prokaryotes are different than the flagella in eukaryotes. This means that the flagella of bacterial, archaea, and eukaryotes arose independently. Therefore, they are analogous structures Parts of a bacterial flagellum. -Motor, hook, filament -Bacterial flagellum evolved as other proteins were added to the old system. This is known as exaptation existing structures take on new functions through descent with modification Prokaryotic DNA -Don’t have a nucleus -DNA located in the nucleoid -Have plasmids rings of independently replicated DNA Reproduction Binary fission I cell divides into 2, then 4, then 8 etc Meiosis and fertilization do NOT occur in prokaryotes Concept How are prokaryotes able to be diverse if they reproduce by Binary fission? 1. They rapidly reproduce 2. High rates of mutation. Since they can reproduce so quickly, the chances of getting mutations is higher 3. Genetic recombination combination of DNA from 2 sources Transformation take DNA from surroundings. Foreign DNA can be put in genome by homologous DNA exchange Transduction phages carry prokaryotic genes from one host cell to another Conjugation DNA is transferred between 2 prokaryotic cells via sex pili. Only one of the cells needs the F factor (F+) to be a donor. The F- cell is the recipient Resistance R plasmids- plasmids that carry resistant genes. Natural selections favors those that are resistant. Which is why antibiotics need to be used only when necessary. Oxygen in metabolism Obligate aerobes- need O2 for cellular respiration Obligate anaerobes- are poisoned by O2 Anaerobic respiration- use nitrate ions or sulfate ions to accept electrons instead of O2 on the electron transport chain Facultative anaerobes- can use O2 but also use fermentation or anaerobic respiration Nitrogen in metabolism Nitrogen fixation- incorporate nitrogen in amino acids and organic molecules -Nitrogen fixing cyanobacteria are highly self-sufficient Nitrogen fixing prokaryotes increase the nitrogen available to plants Metabolic cooperation Prokaryotes “work together” and use resources they couldn’t by themselves Heterocysts- carry out only nitrogen fixation. They deliver nitrogen to nearby cells and in return, they get carbohydrates Biofilms- surface-coating colonies that secrete signaling molecules that recruit nearby cells Bacteria -contain prokaryotic species Proteobacteria -gram negative -phototrophs, chemoautotrophs, and heterotrophs -aneorobic or aerobic Types of Proteobacteria 1. Alpha a. Related to eukaryotic hosts b. Mitochondria evolved from aerobic alpha via endosymbiosis c. Form root nodules and fixes Nitrogen 2. Bamma a. Sulfur Bacteria b. Resides in intestines and is not normally pathogenic c. E. coli, salmonella, cholera d. During the Haiti earthquakes, many died from Cholera because of the camps spread disease quickly, and the UN brought it over 3. Epsilon a. Many pathogens b. Can cause blood poisoning 4. Gram positive bacteria a. Mycoplasms- smallest cells b. Streptomyces- source of antibiotics Archaea -share traits with bacteria and eukaryotes (see table 27.2 for more traits) *don’t have a nuclear envelope like bacteria *don’t have peptidoglycan like eukaryotes *and have some histones, unlike bacteria -More closely related to Eukarya than Bacteria -Tend live in extreme environments, called extremophiles Extreme halophiles- live in saline environments Extreme thermophiles-live in hot environments Methanogens- release methane as a by-product Chemical Recycling Decomposers- break down dead organisms and waste products allowing carbon, nitrogen and other elements to be used by other organisms Cyanobacteria and autotrophic prokaryotes us CO2 to make organic compounds which then are passed through the food chain. They also produce O2 and fix nitrogen Ecological Interactions Symbiosis- 2 species live in close contact with each other Host larger organism Symbiont smaller organism Mutualism- ecological interaction where both species benefit Commensalism- ecological relationship where one benefits and the other isn’t harmed Parasitism- parasite eats the host Pathogens-parasites that cause disease, most of which are prokaryotic Mutualistic bacteria -bacteria live in our intestines that help digest different types of food Pathogenic bacteria -Exotoxins- secreted by bacteria that can cause Cholera. The exotoxin stimulates intestinal cells to release chloride ions into the gut -Endotoxins- lipopolysaccharide of outer membrane of gram-negative bacteria. Toxins are released when bacteria die and cell walls start to break down. Cause salmonella and cause typhoid fever Chapter 28 Most eukaryotes are single-celled organisms -Eukaryotes include protists, plants, animals, and fungi Unlike cells of prokaryotes, eukaryotic cells have a nucleus and membrane enclosed organelles, well- developed cytoskeletons Most organisms in eukaryotic lineages are protists and most protists are unicellular Protists can be nutritionally diverse -Photoautotrophs -Heterotrophs -Mixotrophs Sexual Reproduction- protists can reproduce sexually or asexually Protists have origins in endosymbiosis -Mitochondria evolved by endosymbiosis of an aerobic prokaryote. -Plastids evolved by endosymbiosis of a photosynthetic cyanobacterium -Plastid bearing lineage of protists evolved into read and green algae -Red and green algae underwent secondary endosymbiosis. Secondary endosymbiosis- ingested in the food vacuoles of heterotrophic eukaryotes and became endosymbionts themselves. The Super groups of Eukaryotes -it is no longer thought that amitochondriates are the oldest lineage -one hypethesis divides all eukaryotes into 5 super groups, but the book only divided them into 4 groups, so it’s still controversial 1. Excavata a. Feeding group characterized by its cytoskeleton because it has a feeding groove on the side of its body b. Includes diplomands, parabasalids, and euglenozoans -Diplomonads- They have mitosomes and some of their parasites cause Giardia -Parabasalids- they have hydrogenosomes and the pathogen Trichomonas vaginalis causes yeast infections -Euglenozoans is a diverse clade with spiral or crystalline rods in flagella with unknown function *Kinetoplastids- have 1 mitochondria that as a mass of DNA called kinetoplast *Euglenid- has a pocket at one end of cell where 1 or 2 flagella emerge. Some are mixotrophs 2. SAR clade a. Has 3 diverse clades: Stramenopila, Alveolata, and Rhizaria b. Many are photosynthetic c. Many of the groups are thought to have arisen by secondary endosymbiosis -Alveolata- membrane bound sacs called alveoli are just under the plasma membrane. -Includes dinoflagellates, apicomplexans, and ciliates. *Dinoflagellates- are aquatic mixotrophs and heterotrophs and are reinforced by internal plats of cellulose. They cause red tides *Phylum Apicomplexa- They are parasites of animals and their apex has organelles specialized for penetrating their hosts. They have sexual and asexual stages and they have a plasmodium parasite that causes malaria. -Phylum Stramopila- they are diatoms that are unicellular algae with a 2 part wall of hydrated silicia. -Rhizaria- are a monophyletic clade made up of amoebas that move and feed by pseudopodia. It includes forams and radiolarians that have hard shells and tests and the pseudopodia extend through holes in the test. 3. Chromalveolata -monophyletic and originated by endosymbiosis with red algae -controversial clade that includes the alveolates and stramenopila (the book puts these in the SAR clade) 4. Archaeplastida a. Contain red and green alage and land plants b. Heterotrophic protist acquired a cyanobacterial endosymbionts c. Photosynthetic descendents evolved into read and green algae d. Land plants are descended from green algae 5. Uniknots a. Includes animals, fungi and closely related protists b. Also includes Amoebozoans that have lobe or tube shaped pseudopodia Algae! 1. Golden algae a. Most are unicellular, but some are colonial b. Contain yellow and brown carotenoids 2. Brown algae a. Largest and most complex algae b. All are multicellular and most live in marine environments c. Body is plantlike but the body of brown algae is called a thallus. d. The thallus has root like holdfast whose purpose is to anchor the algae. Also has stem like stipe that supports leaf like blades 3. Red algae a. Multicellular and are largest seaweeds b. Red due to their accessory pigment phycoerythrin 4. Green algae a. Has 2 main groups, the chlorophytes and charophyceans b. Most live in freshwater, other live in damp soil or snow. (In the snow, they look pink) Alternation of Generations -life cycle where there hare haploid and diploid forms -heteromorphic- generations are structurally different -isomorphic- sporophytes and gametophytes looks similar but differ in chromosome number Plasmodia slime molds -Not multicellular, it is a single mass of cytoplasm that is undivided by plasma membranes and contains many nuclei. -Product of mitotic nuclear divisions that aren’t followed by cytokinesis. Cellular slime molds -all haploids in life cycle are asexual -stalk and spores are very similar and closely related -in sexual reproduction, the diploid zygote undergoes meiosis and amoebas are haploid Chapter 29 Timeline of plants Cyanobacteria-3.4 billion years old Green algae- 1 billion years old Ferns- 370 million years old First seed plants- 300 million years old Chlorophytes and charophytes (which are algae) are most closely related to land plants Charophyte algae are small because they are just a collection of cells that don’t have a means of transporting nutrients, therefore they must be near water. How did plants start moving to land? -Sporopollenin- prevent zygotes from drying out in charophytes Why did plants do well on land? -No competition of sunlight -Lots of CO2 available -Lots of nutrients in the soil -There were few herbivores and pathogens What are some of the problems being on land? -Lack of water -Lack of structural support All land plants have 4 traits that charophytes don’t have 1. Alternation of Generations 2. Sporangia where spores are formed 3. Gametangia where gametes are formed 4. Apical meristems Some land plants have other traits that charophytes and other plants don’t have 1. Cuticle waxy coating that prevents water loss 2. Secondary compounds can be toxic compounds that are used as defense against herbivores and other compounds that protect from UV radiation Nonvascular plants are Byrophytes which are… -Liverworts hepaphyta -Hornworts Anthocerphyta -Mosses Bryophyta Vascular plants -Seedless -Seeds Vascular tissues carry nutrients to the plants. Therefore, Byrophytes do not grow very tall and stay close to the ground Life cycle of mosses Figure 29.6 1. After meiosis, spores are haploid and male or female 2. Spores grow in gametophytes a. Anteridia where sperm is produced (male) b. Archegonia where eggs are produced (female) 3. Sperm move via water and fertilize egg in Archegonia 4. Zygote is then diploid 5. Sporophyte grows on parent plants 6. Cycle repeats Alternation of Generations 1. Gametophyte is haploid and produces haploid gametes via mitosis 2. Fusion of gametes result in diploid sporophyte which make haploid spores 3. Diploid embryo stays in tissue of female gametophyte 4. Placental transfer- nutrients transfer from parent to offspring Byrophyte Sporophytes -Are the smallest sporophytes of all extant plant groups, which stays consistent with the hypothesis that larger sporophytes evolved later in vascular plants -A bryophyte sporophytes consists of a foot, a seta, and sporangium -foot embedded in the archegonium where it absorbs nutrients from the gametophyte -seta a stalk that conducts the absorbed nutrients to the sporangium -sporangium uses these nutrients to produce spores by meiosis -The top of a sporangium capsule has a peristome that opens up in dry conditions and releases moss spores. Why are mosses important? -Mosses can colonize bare soil and help retain nitrogen soil. -Can habit extreme environments such as mountain tops, tundra, and desserts. -Ability to live in dry conditions for long periods of time -Phenolic compounds in moss can absorb UV radiation -Peat moss is used as a fuel sources in Europe and Asia -Peat moss contains 30% of the world’s soil carbon which stabilizes CO2 concentrations. Unless global warming continues, water levels will drop and peat will be exposed to the air. Then peat will begin to decompose and release stored carbon Ferns and other seedless vascular plants were the first plants to grow tall -Unlike the nonvascular plants, early vascular plants had branched sporophytes that were not dependent on gametophytes for nutrition. -The ancestors of vascular plants had life cycles with dominant sporophytes, transport in vascular tissues called xylem and phloem, and well-developed roots and leaves, including spore-bearing leaves called sporophylls. -Xylem bring water and minerals in tube-shaped cells called tracheids that carry water and minerals up from the roots. -Water conducting cells have lignin that strengthens their cell walls -Phloem- transports sugars, amino acids, and other organic products Leaves increase surface area of the plant body and serve as the primary photosynthetic organ of vascular plants. -Only lycophytes (oldest lineage of extant of vascular plants) have microphyulls small spine-shaped leaves supported by a single strand of vascular tissue -All other vascular plants have megaphylls leaves with highly branched vascular system Spore Variations -sporophylls modified leaves that bear sporangia -Fern sporophylls have clusters of sporangia called sori that is on the undersides of the sporophylls -In lycophytes and gymnosperms groups of sporophylls form cone-like structures called strobili -Homosporous one type of sporangium that produces one type of spore. Most seedless vascular plants are homosporous -Heterosporous plant species that has 2 types of sporangia and produces two kinds of spores Chapter 31 Fungi -Fungi are diverse and widespread -Good for ecosystems because they break down organic material and recycle vital nutrients How do fungi obtain nutrients? -heterotrophs absorb nutrients from outside their bodies. They use enzymes to break down molecules into smaller organic compounds Body structure of fungus -most common are multicellular filaments and single cells called yeasts -Some can grow as both filaments and yeast, others only grow just as filaments -Hyphae network of tiny filaments that consist of tubular cell walls surrounding the plasma membrane and cytoplasm of the cells -Chitin strong and flexible polysaccharide that provides strength to the cell walls and enhance feeding by absorption. -Septa cross-walls that divide hyphae. Septa have pores large enough to allow ribosomes, and mitochondria flow from cell to cell. -Coenocytic fungi fungi that lake septa. They have a continuous cytoplasm having hundreds of nuclei -Mycelium an interwoven mass that that infiltrates the material on which the fungus feeds. -Mycorrhizae mutually beneficial relationships between fungi and plant roots. Mycorrhizal fungi have specialized hyphae called haustoria. Haustoria are used to extract or exchange nutrients with their plant hosts. There are 2 main types of mycorrhizal fungi 1. Ectomycorrhizal fungi form sheaths of hyphae over the surface of a root and typically grow into the extracellular spaces of the root cortex 2. Arbuscular mycorrhizal fungi extend branching hyphae through the root cell wall and into tubes formed by pushing inward. Mycorrhizae are important in ecology and agriculture because almost all vascular plants have mycorrhizae and rely on them for nutrients. Reproduction Fungi produce spores that can be sexual or asexual. They can produce spores from different types of life cycles. Asexual reproduction -mycelium makes spores that then germinate. All of them are haploids and clones Sexual reproduction -When mycelium touch each other, plasmogamy occurs. Plasmogamy is the union of the cytoplasm of 2 parent mycelia. -A mycelium where the haploid nuclei contributed by each parent that do not fuse right away are called heterokaryon -A dikaryotic mycelium is where the haploid nuclei pair off two to a cell, one from each parent. -Centuries may pass before karogamy occurs. During karogamy, the haploid nuclei fuse and produce diploid cells. -The diploid phase is short-lived and undergoes meiosis, producing haploid spores. Lineages of fungi 1. Chytrids a. Live in fresh water and on land b. Are decomposers, parasites, or mutualists c. Have flagellated spores called zoospores d. Are a paraphyletic group e. The Chytrid fungus thickens frogs’ skin and they die 2. Zygomycetes a. Diverse clade b. Molds, parasites, and commensal symbionts c. Sexually reproduce zygosporangia 3. Glomeromcytes a. Are from arbuscular mycorrhizae 4. Ascomycetes a. Live in fresh water, marine environments, and land b. Have sexual spores in saclike asci, contained in fruiting bodies called ascocarps c. Vary in size and complexity d. Called sac fungi because of their asci e. Have asexual spores called conidia f. Spores are formed at tips of hype called conidiophores 5. Basidomycetes a. Mushrooms, puffballs, and fungi b. Have a club like structure c. 75 species are luminescent Fungi are most closely related to animals Archae are more closely related to Eukarya Peter the Great’s army was wiped out due to ergotism, a fungus that grows on rye and wheat What is a mushroom? -Life cycle of a basidiomycetes usually includes long-lived dikaryotic mycelium -In response to environmental simuli, the mycelium reproduces sexually making basdiocarps (fruiting bodies) Dikaryotic is haploid+haploid Fungus-plant mutualisms -Endophytes live inside plants and create toxins that deter herbivores and defend against pathogens Fungus-animal symbiosis -fungi share digestive services with termites and ants. They break down food into simpler compounds that the termites and ants can eat. Lichens -symbiotic relationship between a photosynthetic microorganism and a fungus -Most often ascomycetes, sometimes basidiomycetes -algae or cyanobacteria occupy an inner layer below lichen surface -algae give carbon, cyanobacteria give nitrogen, and fungi give a place to grow. 3 Forms of lichen 1. Fruticose (shrub-like) and is a primary food source in the tundra 2. Foliose (leaf-like) 3. Crustose (crust-like) Humans and lichens -used as dyes, perfumes, and incense -lichens are susceptible to air pollution For sexual reproduction: most of the time after fertilization, the spore or gamete is diploid. After meiosis the spore or gamete is haploid Asexual is haploid Fungi- have a heterokaryotic (unfused nuclei from different parents) phase after plamogamy and ends at karyogamy. After Karyogamy, it’s diploid. After meiosis, its haploid. When asexual, it’s all haploid END OF MIDTERM 1 Midterm # 2 Study guide Phylum Gnetophyta -has 3 genera -tend to thrive in desserts and tropics -cones are fleshy Genus Ephedra -located in the Southwest dessert -uses: meth Genus Welwitschia -located only in Southwest Africa -2 leaves keep growing and will split, giving appearance that there is more than just 2 leaves -endangered, have the ability to live hundreds of years Phylum Coniferophyta -largest gymnosperm phyla -majority are evergreens -photosynthesis during all seasons -sailors planted the North American pine on islands to use them for masts if they ever got stranded Douglas fir -used for housing development European larch -located in Swiss Alps Bristlecone Pine -located in California and Colorado up in the mountains -Grow very slow, enabling them to live thousands of years. Sequoia -largest organism based on volume and mass -Climate change threatens its existence Wollemia pine -naturally found in Australia -thought to be extinct Lazarus effect Common Juniper -used for spice and gin In case of gymnosperms, the tree would be the sporophyte -Sporophyte is 2n -Microsporangium (2n) are inside the cones -Pollen grains are (n) -Pollen grains go through meiosis when they land on the ovule Angiosperms 5 traits of seed plants 1. Reduced gametophytes (microscopic gametophytes protected by sporophytes) 2. Heterospory (spores of 2 sexes) 3. Ovules 4. Pollen 5. Seeds Angiosperms have one phylum, the anthophyta. -have flowers, fruits, and seeds Flower -Tend to have successful reproduction because they attract pollinators and animals. This makes flowers very diverse. -have different colors, scents, and symmetry Amorphophallus titanium -largest unbranched inflorescence -blooms for a few days -corpse flowers fragrance imitates rotting flesh to attract flies for pollination -located in Sumatra -can reach 6ft tall RAfflesia schadenbegiana -corpse flower -largest florescence in diameter -blooms for 5 days -located in Indonesia and Malaysia Wolffia Arrhizia -smallest angiosperm Sepal-modified leaf that surrounds the bud Petal-modified leaf Stamen and carpel- highly modified leaves Carpel -has the ovary, style and stigma -stigma receives pollen -style is where pollen lands Pistil fused carpels Female gametophyte embryo sac that develops in the ovule Stamen Has the microsporophyll, anther, and pollen sacs (also known as microsporangium) Complete Flower -has all 4 modified leaves (petals, sepal, carpel, stamen) Incomplete flower -don’t have 1 or more of the modified leaves Perfect flower -has male and female parts All complete flowers are perfect flowers, but not all perfect flowers are complete Selfing plants plants that are able to pollinate themselves. -perfect plants can self-pollinate Ways to prevent selfing -gametophytes are incompatible -pollen tube doesn’t grow due to certain proteins -stamens and carpels can be different lengths -sporophytic self-incompatibility the sporophytes fail Pollen -dispersal method influenced shape and function of pollen grains -outside of pollen has sporopollenin Life cycle of angiosperm 1. Microsporophytes (2n) undergo meiosis and produce a microspore (n) 2. Ovule (2n) undergoes meiosis and produce megaspore (n) 3. Pollen grain land on stigma, grows down to ovary and 2 sperm enter the egg, fertilizing it 4. Have a zygote (2n) and triploid tissue (3n) becomes endosperm that provides nutrients 5. Embryo is (2n) and breaks loose of seed coat (2n) and germinates Cotyldons -1 or 2 first seed leaves in angiosperms -2-24 for gymnosperms Hypogeal cotyledons -aren’t able to photosynthesize because they are underground -function store starch Epigeal cotyledons -photosynthesize because they are above ground -when seed is germinated, the epigeal cotyledons break through the seed coat Fruit -ovary that has matured -can be fleshy or dry -function seed protection and dispersal Simple fruits -single or compound ovary -in a single carpel Simply fleshy -berries, drupes -Berries single ovary Ex bananas, oranges, blueberries, tomatoes Pipo watermelons, squash, pumpkins. Special berries with a tougher exterior -drupes exocarp and mesocarp is fleshy, but has a hard endocarp. Ex stonefruits, coconuts, mangos, olives Aggregate -single flower with many carpels -blackberries Multiple -Inflourescence several flowers fuse together -Every fruit came from one of those flowers -Fruits merge together -pineapple and figs (in figs, the flower is inside and is pollinated by the fig wasp) Bread fruit Joseph Banks wanted to bring this fruit to provide substantial food to slaves. But his sailors mutinied and remained on the island. By the time Banks brought back the bread fruit trees, slavery was abolished Simple dry fruits -dandelions and dots on strawberries Legume -clover, peanuts, beans, soy -Aspergillus fungus that attacks peanuts and causes liver cancer Nut -The wall of the ovary turns into a hard coating/shell Indacesent don’t open when mature -acorns Angisoperm diversity 1. Monocots once cotyledon 2. Eudictos 2 cotyledons and “true” dicots Basal Angiosperms -3 oldest lineages 1. Amborella trichopoda 2. Star Anise 3. Water lilies Magnolids -closer in relation to monocots and eudicots than basal angiosperms -Laurels, black pepper plants, magnolias Monocots -make up 25% of angiosperms -60,000 species -Multiples of 3 -Parallel veins Palms -around at end of the Cretaceous period -2,600 species -Tropical -Talipot palm largest inflorescence due to their leaves being 5m in diameter. They produce once then they die Grasses -10,000 species -Family Poaceae -Bamboos, wheat, sugarcane, rye, maize Orchids -22,000 species -bilaterally symmetric -could be largest family of angiosperms. Asteraceae is a close second Eudicots -2/3 of angiosperms -2 cotyledons -veins are net like - vascular tissue arranged in a ring -taproot -3 openings on pollen grain -multiples of 4 or 5 Angiosperms and animals -Flowers that are bilateral symmetrical tend to have more species than those that are radially symmetrical. -Why? -Bilateral can be more specific to certain pollinators -Bilateral tend to affect the movement of pollinators more than radial -Gene flow is decreased in diverging populations Plants and people -seed plants are packed with nutrients important for human civilization -80% of food crops are wheat, rice, maize, potatoes, cassava, and sweet potatoes -Artificial selection has led to modern crops Threats to biodiversity -loss of habitat (affects both plants and animals) -within 100-200 years, we could lose 50% of plant species Plant structure 3 main organs 1. Roots transport water and minerals 2. Stems used for support 3. Leaves transport sugars Roots -multicellular -anchor the plant -absorb water and minerals -store nutrients Root hairs -increase surface area to absorb more water and minerals Taproot -1 main root -lateral roots branched Advenitious roots arise from stems or leaves. Includes… 1. Fibrous roots a. Seedless vascular monocots 2. Proproots a. Aerial roots b. Provide support 3. Strangling roots a. Support plant by growing around objects b. Strangler fig i. Epiphytes ii. Roots grow down and around the tree iii. Stem grows up 4. Climbing roots a. Provide support b. Negatively phototrophic grow towards darkness and away from light stimulus Pneumatophores -roots that grow above ground -allows for gas exchange in wet and flooded environments -common in mangroves Buttress roots -provide support Storage roots -taproots -lateral roots -store carbohydrates Haustorial roots -parasitic plants -use other plants to obtain water and nutrients -Ex mistletoe, dodder, snow plants Stem -nodes place where leaves are attached -internodes part of stems that are between the nodes Axillary bud -produce a lateral shoot or branch Apical bud -located at shoot tip -helps young shoots grow taller and elongate Modified stems Corm -storage stem located beneath the surface -Ex taro, gladiolus, saffron Rhizome -horizontal -beneath the surface -sends out roots and shoots -Ex ginger, poison grass, Bermuda grass Stolon -horizontal along the top of the ground -advenitious roots -at the end of each stem is a clone -Ex strawberries and several grass species. Bulbs -underground stems -modified leaves -function storage during periods of dormancy -Ex garlic and onions Leaves The leaves of most vascular plants are the main photosynthetic organ Types of leaves 1. Simple leaf single leaf per stem 2. Compound leaf complex petiole 3. Double compound leaf has several leaflets Modified leaves Bract -part of reproductive structure -tend to be brightly colored -usually confused as the flower, but it’s not the flower Ex poinsettia Tendrils -function climbing and attaching to surfaces -can photosynthesize -thigmotrophic stimulus is touch Ex pea plant Spines -modified leaf -used for defense -seen in xeriphytes plants that prefer dry environments Thorns -modified stem Prickles -modified epidermis -Ex roses (the nomenclature usage of thorns referring to roses are actually prickles) Storage leaves -store water, nutrients, and toxins Succulents -cacti -iceplants -agave 3 types of tissues -Dermal -Ground -Vascular Dermal tissue Epidermis on non-woody plants Cuticle a waxy coat that minimizes loss of water from the epidermis Periderm -also in woody plants -protective tissue -the epidermis in older regions of stems and roots get replaced by periderm Trichomes- small hairs on the shoot that prevent insect damage Vascular tissue -moves materials back and forth between the roots and shoots over long distances -2 types of vascular tissue xylem and phloem Xylem moves water and minerals from roots to shoots Phloem move nutrients to where they are needed most in the plant Stele vascular tissue of a stem or roots -solid cylinder stile in lots of angiosperms Ground tissue -neither dermal or vascular -pith ground tissue internal to vascular tissue -cortex ground tissue external to vascular tissue -ground tissue can function as storage, support, and photosynthesis Cellular structure in plants 5 types 1. Parenchyma 2. Collenchyma 3. Sclerenchyma 4. Xylem water cells 5. Phloem sugar cells Ground tissue is composed of… 1. Parenchyma 2. Collenchyma 3. Sclerenchyma Parenchyma -primary walls are flexible -has a central vacuole -used for storage -photosynthesizes -can divide and differentiate -doesn’t have secondary walls -least specialized Collenchyma -strands -provide structural support for young plants - walls are thick and uneven -doesn’t have secondary walls -not as flexible as parenchyma, but a little flexible so that it doesn’t restrain growth Sclerenchyma -rigid -does have secondary cells walls -when cells mature, they’re dead 2 types 1. Sclereids a. Irregular and small shape b. Thick and lignified secondary walls c. Provides the hardiness in nutshells and seed coats 2. Fibers a. Long and slender threads b. In flax and hemp Cells gets energy to build large cell wall, but in order for nutrients to flow, the cell must die at functional maturity. They still provide structure even when dead Vascular cells Tracheids -in all vascular plants -tubular, long and dead -water moves through pits in the tracheids Vessel Elements -short and large -form vessels when aligned end to end Both tracheids and vessel elements are dead at functional maturity and their function is to move water Phloem cells 1. Sieve tube elements a. Alive at maturity b. Don’t have organelles or a nucleus c. Let sugar flow 2. Sieve plates a. End walls have pores that let fluid move between cells in the sieve tube 3. Companion cells a. One per sieve-tube element b. Have nucleus and ribosomes that function for the companion and sieve tube cells Parenchyma photosynthesizes and stores nutrients, therefore it does the majority of metabolic functions Cell growth Indeterminate growth- growth that happens during all of plant’s life Determinate growth- stop growing once an organ reaches a certain size, such as leaves Annuals- life cycle is complete within a year Biennials- complete life cycle within 2 seasons Perennials- can live for several years Meristems -embryonic tissue -indeterminate growth -can differentiate Apical meristems -tip of axillary buds, roots, and shoots Primary growth -vertical growth Secondary growth -grows in thickness in wood plants, which is caused by lateral meristems 2 lateral meristems 1. Vascular cambium a. Adds vascular tissue, secondary xylem and secondary phloem 2. Cork cambium a. Replaces epidermis with periderm b. Periderm makes it thicker and tougher Roots Root cap -dead -grows into the dirt protects the meristem tissue There are 3 zones 1. Zone of division 2. Zone of elongation 3. Zone of differentiation Lateral roots -growth happens at the peridermal layer -the vascular tissue follows the roots -the root will break through peridermal tissue Stems Monocots -lack pith and cortex -have ground tissue -vascular bundles are scattered Leaves Palisade mesophyll photosynthesis occurs here Bundle sheath covers the vascular tissue Spongy mesophyll has gaps that enable gas exchange to occur. Stoma the guard cells maintain a balance between moisture and CO2 Secondary growth -meristematic cells is 1 layer of the vascular cambium -develops from undifferentiated parenchyma cells -secondary xylem accumulates and has tracheids, vessel elements, and fibers -early wood increases flow of water in spring -late wood increases amount of cells used for support during late summer -in perennials, the vascular cambium is dormant Tree rings where late and early wood meet Heartwood -old layers of secondary xylem -doesn’t move water or minerals anymore -used for support Sapwood -moves material through xylem Second phloem -doesn’t accumulate, breaks off over time Morphogenesis homeotic genes change structure of plants Cellular differentiation -produce different proteins that enable cells to become different in their function in structure despite of their common genome Homeotic genes positional information Positional information -young cells aren’t dedicated to a certain function. Their function is determined by their final position Phase changes -developmental phase -juvenile phase to adult phase -phases occur in the shoot apical meristem -juvenile is defined by not being able to flower -hormones and gibberellic acids regulate phase changes Genetic control -vegetative growth to reproductive growth = flower formation -requires meristem identity genes to be turned on. Others need vernalization -environment and internal cues are responsible for triggering growth Organ identity genes -regulate floral patterns -MAD box genes Misplaced structures are due to Hox genes ABC flower development 4 genes responsible for forming floral organs A= sepals A+B= petals B+C= stamens C= carpel Turgid- the cell membrane is pushed against the cell wall When plants wilt, it’s caused by lack of water, because water also provides structure for plants Permanent wilting point point of no return. The plant will not rebound Aquaporine -Transport proteins -In the cell membrane, and their function is let water through and restrict solutes coming in Rate of water movement is regulated by phosphorylation of aquaporine proteins. Transport control -compartmental structure -Plasma membrane regulates which molecules enter -vascular membrane regulates transport between cytosol and vacuole Water and sugars -The cytosol and cell wall are continuous -Symplast cytoplasmic continuum -Plasmodesmata cytoplasm of neighboring cells is connected by channels -Apoplast continuum of cell walls and extracellular spaces -Transmembrane route through apoplast and symplast route Routes Symplastic route via cytosol Apoplastic route via cell walls and extracellular spaces Long distance -Bulk flow movement of fluid driven by pressure -Water and solute move through tracheids and vessel elements of xylem and sieve-tube elements of phloem Absorbing water -root tips where water and minerals are absorbed -root hairs increase surface area -water crosses the cortex via symplast or apoplast Endodermis -Inner layer in root cortex -Around the vascular cylinder -Last stop for passage of minerals to enter the vascular tissue Casparian strip -waxy -has an endodermal wall that doesn’t allow apoplastic transfer into the vascular cylinder Bulk flow is driven by negative pressure in the xylem Xylem sap bulk flow replaces water loss -sap is pulled by roots and pushed by leaves What causes root pressure? -During the night, the root cells put mineral ions into the vascular cylinder xylem and lowers water potential Root pressure -water flows in from the root cortex -Roots have greater pressure than leaves Guttation excess water forms as droplets on tips of leaves Positive root pressure -weak -slightly aids in bulk flow of xylem Negative leaf pressure -Results due to transpiration -the negative pressure pulls on water that’s in the xylem -water is then pulled into the leaf Hydrogen bonds link water together. Adhesion allows water to “stick” to surfaces, preventing gravity from pulling water back down Stomata -account for the majority of water loss, up to 95% -3 cues 1. Light increases the uptake of potassium 2. decrease of carbon dioxide in leaf 3. internal clock (circadian rhythm) How stomata open -potassium goes into cell and water flows in to open -potassium goes out of cell and water goes out to close Desert adaptations -reduced leaves= fewer stomates -CAM CAM -at night, the stomata open -carbon dioxide is stored as malmate -majority of CAM species are angiosperms, but can also be ferns, gymnosperms, and monocots Sugar source to sugar sink -sugar source leaves produce the majority of sugars used by the plant -sugar sink consumers of sugar, tend to be bulbs or tubers -The season also determines what is a sink and source. In the summer, leaves are sugar sources. But in the winter, the leaves die. Now storage organs are sugar sources Sugar movement -moves via sieve-tube elements -can move symplastic and apoplastic -needs a cotransporters Water gets pulled by companion cell and phloem Xylem negative pressure. Bulk flow Phloem positive pressure Phloem -electrical signaling occurs in the phloem -moves macromolecules and some RNA through plasmodesmata Water and Sugar Algal ancestors could get minerals and carbon dioxide from the water Xylem and phloem are important in evolutionary history because they enabled plants to grow tall to compete for sunlight, increase the area of dispersal, and allow them to live on land. This is because xylem and phloem allow minerals and nutrients to travel long distances. Leaf area index upper leaf surface/ surface area of land Light absorption can also be affected by leaf orientation Self-pruning photosynthesis decrease below the basal respiration, which is when leaves don’t get the minimum amount of light in order to carry out their function Leaf Orientation -Affects rate of photosynthesis -Affects rate of water loss Diaheliotropism follow the sun Paraheliotropism avoids sun to retain more water Roots and Shoots When plant cells absorb minerals, nutrients, and water, this is when transport starts Selective permeability what is allowed into and out of the cell Diffusion -does not require energy -passive movement Facilitated diffusion -moves solutes across a membrane -most of the time needs transport proteins to facilitate movement Both diffusion and facilitated diffusion are forms of passive transport Active transport -Carrier proteins -create a hydrogen ion concentration gradient = potential energy -membrane potential like voltage. It is the difference between the interior of a cell and outside fluid The transport of solutes is caused by the energy in the proton gradient and membrane potential Proton pump -causes membrane potential and the proton gradient Cotransport -transport protein that works in pairs to allow the diffusion of a solute and active transport of another solute. -this is how sucrose is taken in by plant cells Diffusion of water Osmosis -water moving down its potential gradient across a semi-permeable membrane -affected by pressure and concentration Water potential -measures solute concentration and pressure -determines the direction of water -water goes from high water potential to low water potential -measured in MPa megapascals -0 MPa at sea level, room temp, and if it’s pure water -Solute potential (s) number of dissolved molecules. Also called osmotic potential -Pressure potential (p) the pressure on a solution Water potential= P + S Soil and nutrition Fragile ecosystem -top layer gives water and nutrients to plants -Organisms that live in the soil. Plants, bacterial, Insects, fungi, and nematodes Soil stratification -layers known as horizons -topsoil uppermost layer Smallest molecule to largest Clay silt sand Topsoil has living and dead organism and minerals and humus Loams -combo of silt, sand, and clay -very productive for plant growth A horizon topsoil. Living and decaying things are here B horizon less weathered rock C horizon parent material, and partially broken rock Inorganic -cations (potassium, calcium, magnesium) adhere to anion -prevents leaching Cation exchange cations are displaced by other cations Root hairs have an affinity for negative ions Acid rain -increases the proton concentration in soils. -important cations are dislodged -rain leaches the important nutrients Nitrogen oxide -fossil fuels Sulfur dioxide -Burn coal. When comes into contact with water becomes sulfuric acid Soil conservation Agriculture impacts -decrease nutrients -increase erosion -strains water -soil compaction Ogalla Aquifer -formed during the Ice Age and by glaciers -Aquifers near coasts are becoming saline. Fresh water sits on top of salt water, but we’ve tapped into that resource too much Pivot irrigation -minerals in water don’t evaporate and land becomes salty Drip irrigation -use less water and a decrease in salt Australia -2.5 million hectares are salinized. Fertilization -replaces lost minerals -Commercial fertilization adds nitrogen, phosphorous and potassium -Organic fertilization is manure, fish meal and compost -Natural fertilization is letting fields go fallow and doing crop rotations Modern agriculture -monoculture -fertilizer and bacteria dominated Control erosion -wind and water erode away topsoil -loss of nutrients -contour plowing -Use windbreaks -terracing hillsides -no till Nutrients -elements needed in order for a plant to finish their life cycle Macronutrients 9 that plants need in large amounts Carbon, oxygen, hydrogen, phosphorous, sulfur, potassium, calcium, magnesium, nitrogen Micronutrients plants need these only in small amounts Iron, manganese, boron, zinc, nickel, copper Rhizosphere- soil bound to roots -high microbial activity -roots secrete sugars, amino and organic acids Co-evolutionary relationship between plants and bacteria Rhizobacteria -free living -function in the rhizosphere -have the ability to enter roots -stimulate plant growth by making hormones -protect roots from disease by making antibiotics -make nutrients available Inoculation of seeds with rhizobacteria increases crop yields Bacteria and the nitrogen cycle 1. Nitrogen is in the atmosphere 2. Nitrogen goes into nitrogen fixing bacteria and organic material goes into ammonifying bacteria 3. Both the nitrogen fixing bacteria and ammonifying bacteria produce NH3 4. H+ from the soil makes NH4 5. NH4 can be used by plants 6. Nitrifying bacteria take NH4 and convert it to NO3 7. Denitrifying bacteria take NO3 and put N2 back into the atmosphere Legume roots -nodules infected with bacteria -bacteroids are in root nodules -bacteria give N2 and get sugar from plant Reproduction of angiosperms -pollen tube fertilizes egg -2 sperm go into the ovule -2n zygote grows into an embryo -ovary walls mature into a fruit -seed coat comes from integument which comes from the sporophyte (grand parents) -sperm comes from the parental generation Microsporangium -microsporocyte is 2n -4 microspores after meiosis n Megasporangium -megasporocyte is 2n -meiosis 1 n megaspore -mitosis 3 antipodal, 2 polar nuclei, egg, 2 synergids 2 polar nuclei + sperm= 3n endosperm 1 egg + 1 sperm = 2n zygote Zygote divides and terminal end grows Basal cell orientates the growing embryo Plant sexuality -angiosperms can be sexual and/or asexual -sexual= genetically different -asexual= can result in a clone Fragmentation separations of a parent plant into parts that eventually develop into a plant Parent root system give rise to adventitious shoots Apomixis asexual reproduction of seeds from diploid or haploid cell Forms of apomixes Nonrecurrent haploid gametophyte leads to a haploid individual Recurrent meiosis is not completed Adventive embryo arises from integument Vegetative flower replaced by a bulb Vegetative reproduction -asexual -beneficial for a successful plant -clones vulnerable if there’s a change in environment END OF MIDTERM 2 Midterm 3 Study Guide Animal Diversity and Evolution notes 3 Domains 1. Bacteria 2. Eukarya 3. Archaea Eukaryan Diversity -protists -plants -fungi -animals Choanoflagellates sister group of animals Metazoans another name for animals There are more animals than any other group. 70% of them are insects (number of species) Prokaryotes have been around longer than animals What are animals? 1. Multicellular 2. Ingestive heterotrophs 3. Move under volition 4. Lack cell walls, but have extracellular matrix 5. Unique, specialized cells: muscle and nerve cells 6. Sexual reproduction 7. 2n dominant 8. Flagellated sperm, non-motile egg 9. Most have larval stage 10. Cells organized into tissues 11. Conserved genes control development (hox genes) 12. Zygote undergoes cleavage, forms blastula gastrulation I-Clicker question: Nearly all animal phyla evolved in which era? A: Cambrian Eumetazoa true tissues Metazoa basal node -sponges are most primitive Origin of multi-cellularity -choanoflagellates are the unicellular sister group to animals -similar to sponges Origin of bilateral symmetry, nervous system, and cephalization -cephalization to form a head -sponge has no symmetry -radial symmetry flower -bilateral symmetry ability to form a head. Example beetles Echinoderms -sea stars have pentaradial symmetry but their larvae have bilateral symmetry Bilateral symmetry -nervous system is located at the head which aids in directionality -become effective predator and consumer Bilateria -genetic mechanism that is responsible for bilateral symmetry and cephalization Embryonic tissue -diplobastic 2 tissue layers -triploblastic 3 tissue layers Origin of coelom -animals are tubular Acoelomate doesn’t have a coelem Coelomate coelom lies within the mesoderm Pseudo coelomate false coelom. Has a body cavity that is touching both the mesoderm and endoderm I-Clicker Q: Do jellyfish have a coelom? A: No Protostome and deuterostome development Protostome means “first mouth” -Spiral and determinate cleavage -First hole that develops is the mouth Deuterostome means “second mouth” -Radial and indeterminate cleavage -Fate of cell not yet determined -First hole that is formed is the anus Deuterostome evolved once, protostome evolved a few times Deuterostome -humans -Chordata -Echinodermata -Hemichordata Almost everything else is a protostome Origin of Segmentation -all animal groups show segmentation -hox genes common genes for segmentation Benefit of segmentation -different parts of the body can specialize for different functions Invertebrates I Notes Big 9 Animal phyla 1. Porifera (sponges) a. Habitat mostly marine b. Motility sessile c. Diet filter feeding 2. Cnidaria a. Habitat mostly marine b. Motility motile and sessile c. Diet Predatory and filter feeder d. Diversity more than 10,000 species 3. Platyhelminthes (flat worm) a. Habitat moist habitats b. Motility motile c. Diet predator or parasite d. Diversity 25,000 species 4. Mollusca a. Habitat marine, fresh water, terrestrial b. Motility motile and sessile c. Diet predatory, filter feeder, or detrivores d. Diversity 85,000 species 5. Annelida a. Habitat marine, fresh water, terrestrial b. Motility motile and sessile c. Diet predator or parasite 6. Nematoda (most abundant) a. Habitat all habitats b. Motility motile c. Diet parasite or free-living d. Diversity 15,000 species 7. Arthropoda a. Habitat Marine, fresh water, terrestrial b. Motility Motile c. Diet several forms d. Diversity millions 8. Echinodermata (starfish) a. Habitat marine b. Motility motile c. Diet filter feeders 9. Chordata a. Habitat Land, marine, fresh water b. Motility motile c. Diet Lots of forms of feeding Majority of species are found in water, but the most divers (the big 9) are found on land Week 10 Notes Invertebrates II (Lophotrochozoa) Monophyletic group shared ancestry Paraphyletic group exclude a descendent Polyphyletic group includes group of different ancestors Clade monophyletic group I-Clicker question: Where did triploblastic tissue arise? Hermichordata Where did deuterostome development arise? Deuterstomia Where did bilateral symmetry arise? Bilateria 3 Major clades of Bilateria 1. Deuterstomia 2. Lophotrocozoa 3. Ecdysozoa Lophotrocozoa -united by molecular characters -most divers body plans -largest number of phyla 1. Platyhelminthes- flat worms a. Acoelomate b. Flat bodies for a greater surface area to volume ration c. Gas exchange across body surface d. Gastrovascular cavity (not a tube) e. Majority are parasitic, some are free-living f. Have more than one host g. Definitive host used for sexual reproduction h. Intermediate hosts where larvae grow 2. Mollusca a. More than 85,000 species b. Second to arthropods c. Soft body and hardened shell of calcium carbonate d. Shared body plan e. Radula f. 80% are snails and slugs g. Cephalopods are neurologically advanced h. Some are toxic i. Most endangered group 3. Gastropods a. Snails and slugs b. Marine, fresh water, terrestrial c. Mantle what secretes calcium carbonate 4. Bivalves a. Clams, mussels, oysters b. Marine and freshwater c. Have 2 shells d. Foot helps them move and keep in place 5. Cephalopods a. Octopus, squid, nautilus b. Camouflage and chromophores c. Reduced mantle d. Advanced eye, behavior, and intelligence 6. Mollusks a. Most endangered b. Recently discovered that they make the world’s strongest material c. Have visceral, mass and foot Annelida (segmented worms) -chaetae bristles mad of chitin -predators 1. Marine worms a. Errantians-> mobile predators b. Sedentarians sessile 2. Leeches a. Secrete anesthetics and hirudin 3. Earth worms a. Move nutrients and aerate soil b. Common in North America but aren’t native Invertebrates III Ecdysozoa Loveifera Priapula Nematoda Arthropods Ecdysozoa most diverse animal group -external covering -ecdysis molt with growth 1. Nematoda-round worms a. 15,000 species b. Important in decomposition c. Motile d. Cdenorhaloditis elgans i. 1 mm long, simple ii. 959 cells, all mapped used in research 2. Arthropoda a. Most diverse b. Most successful of all animal phyla Myriapods -most ancient lineage -may have been the first to colonize land Trilobites -extinct Crustaceans and insects -insects are a group within Crustacea Characteristics of Arthropod -segmented body abdomen, thorax, head/ cephalon -spiders the head and thorax are combined -they have paired limbs -hardened exo-skeleton and chitin. Exo-skeleton also acts as muscle attachment -jointed appendages -open circulatory system -have a heart, but don't have vessels -hemolymph circulates through hemocoel Insects are most divers -most are beetles Chelicerata (spiders, mites, scorpions) -chelicerae feeding appendages. Some are modified to inject venom -cephalothorax -abdomen -4 pairs of walking legs -pedipalps modified limbs with several function on the cephalothrax Crustacea (crabs, shrimp, copepods, barnacles, amphipods etc) -many pairs of walking legs -antennae evidence that insects and crustacea are related -cephalon, thorax, abdomen -most numerous animals on Earth -highly variable characteristics Barnacles -evolutionary constraints -sessile -modified legs filter feed -sexually reproduce through intermittent organ Insecta (beetles, butterflies, ants, bees, cockroaches, flies etc) -abdomen, thorax, head -antennae -wings for true flight -3 pairs of walking legs -metamorphosis Insect open circulation -have a heart and body cavity -vessels feed fluid through the body -hemolymph carry nutrients -Tracheae and tracheoles -holes on the outside of the body where oxygen enters -oxygen enters the tracheae pathways that travel through the body -Oxygen moves via diffusionreason why insects are small -Giant Weta is the biggest living insect Insects used to be bigger before the oxygen content of the air changed Vertebrates I (Chordate Evolution to amniotes) Deuterstomia -Echinodermata -Hemichordata -Chordata Echinoderms -starfish, sea urchins, sea cucumbers -7,000 species Chordates -65,000 species -notochord- rod in embryo becomes spine in vertebrates -dorsal hollow nerve cord- cephilize head region -pharyngeal slits elements that support the gills that eventually become jaws -post and anal tail anus comes before the tail Amniotes -Reptiles -Mammalia Tetrapods -Amphibia -Reptile -Mammalia Cephalochordata -simple -bury itself in sediment -use mouth to feed -does have the ability to move Urochordata -marine -pulls water in and filters the food products -larvae have all charactrisics of chordates Vertebrates -have complex body plan due to the duplication of Hox genes -spinal cord surrounds bony vertebrae -notochord disappears in development but is present during the embryonic stage Gnatostomes (jawed mouth) -have jaws -incomplete mineralized skeleton -gene duplication -lateral line system -enhanced smell and vision -jaws arose from support structure for pharyngeal slits Osteichtyes (majority of vertebrates) bony fish -ossified means mineralized -they have a complete ossified endoskeleton -modified lungs Actinopterygii -most diverse of the vertebrate group and ray finned fishes -inhabit all aquatic habits and there are 30,000 species Lobe –Fins (sacropterygii) -lobed fins with bony and muscular support Tetrapods -4 limbs with digits -adults lack gills -vertebrae in neck= head movement -the pelvic girdle is fused to the spine Amphibia -more diverse than mammals -5,000 species of frogs and toads -700 species of salamanders and newts -200 species of caecilians. Also, caecilians can lactate Amniotes -have an amniotic egg that has specialized extraembryonic membranes that are sometimes shelled -ventilate with rib cage Reptilia -diverse -more than 20,000 species -scales composed of keratin -shelled eggs on land -internal fertilization -ectothermic and endothermic Birds, snakes, etc Vertebrates II: Mammals and metabolic trade-offs Amniotes -Reptilia and Mammalia -have the extraembryonic membrane to prevent eggs from drying out (desiccation) -this gave them the ability to colonize land Majority of reptile lineage are diapsids 3 Major groups of Mammals (also evolved froma therapsid ancestor) 1. Monotremes a. 5 species b. Don’t have nipples, lactate by sweating c. Platypuses 2. Marsupials a. Short gestation. b. Baby is born in early development c. 300 species d. Kangaroos and opossum 3. Eutherental/ Placenta a. Majority of development in gestation b. 5,000 species Most mammals are rodents and ¼ of mammal diversity comes from bats Characteristics of Mammalia -hair -no other animal group has hair -made of keratin -complex anatomy -found on all mammals in some point of their development -vibrissae whiskers -young a fed milk from modified sweat glands -exceptions are that it is found in pigeons and caecilians -large amounts of parental investment in young -lactation? is more expensive than gestation Mammal characteristics -3 bones responsible for sound (malleus, incus, and stapes). Reptiles only have 1 ear bone -the dentary makes up the lower jaw -Majority of mammals, rely on sou
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