Final Study Guide
Final Study Guide Life103
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This 94 page Study Guide was uploaded by Courtney Potter on Friday December 11, 2015. The Study Guide belongs to Life103 at Colorado State University taught by Shane Kanatous; Graham Peers in Summer 2015. Since its upload, it has received 174 views. For similar materials see Biology of Organisms-Animals and Plants in Entomology at Colorado State University.
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Date Created: 12/11/15
What Is Life? (Introduction) Inanimate objects can take in energy and dissipate the energy, responds to stimuli, can grow by extensions, but CANNOT pass on genes Regulation- being able to control a system in response to external environment Energy processing- obtain energy from environment and convert it to form of energy organism can use to fuel: adaptation, reproduction, growth and development, regulation, order, and responses Animals need to take in energy from ingesting other sources Organisms can vary on what they use as a primary food source: carbs, protein, fat Most animals suck at converting plant material into energy unless they have good relationships with bacteria (symbiosis) Animals take in oxygen and produce carbon dioxide (reflection of metabolism) Key Factors of Life 1 Homeostasis: o Ability to regulate internal systems separate from external environment 2 Organization: o Cells, tissues, organ, organ systems, organisms o All different levels have to communicate to get energy to each single cell 3 Metabolism: o Anaerobic-sprinting, jumping, short term things that happen too fast to need oxygen, form lactic acid o Aerobic- needs oxygen, final electron acceptor in the ETC to create ATP o Basal metabolism- basic amount an animal takes to survive o Maximum metabolism- max energy they can take it 4 Growth: o from cells to organism, ability to change over time 5 Adaptation: o a trait that has a functional role that is maintained and evolved by natural selection 6 Response To Stimuli: o fight or flight 7 Reproduction Classification of Species Domain: 1 Bacteria 2 Archaea a Prokaryotic organisms adapted to extreme environments 3 Eukarya (all need symbiotic relationships with bacteria) a Plantae b Fungi c Animalia d Protists Kingdom. Phylum, Class, Order, Family, Genus Species o Reproductively isolated- parents can reproduce with same species or different, but young will NOT be fertile if parents reproduce with another species Fossils Found in sedimentary rock (strata), amber, and ice Radiometric dating- parent isotopes decay to daughter isotopes at a specific rate varying from different isomers called their half life o Fossils contain different isotopes when they die one stops producing while the other decays, these are compared to date fossils (works better on younger ones) o Old fossils age can be determined by comparing age of volcanic rock around them CHAPTER 25: HISTORY OF LIFE ON EARTH Geologic Time Scale-time scale dividing Earth’s history into four eons The Hadean Eon Big Bang Theory Earth formed 4.6 billion years ago from rock and dust around sun, then hit with chunks of ice and rock Oparin-Haldane Hypothesis: o Earth was a reducing atmosphere (contains hydrogen, carbon dioxide, hydrogen sulfide) o Stanley Miller tested hypothesis and found that amino acids could be produced in that atmosphere o Miller-Valley Experiments produced organic compounds in a neutral atmosphere also o Most likely life started by Alkaline vents where the pH is 9-11 and warm NOT in hydrothermal vents Conditions Facilitating Origins of Life 1 Nonliving (abiotic) production of building blocks: amino acids and nitrogenous bases 2 Formation of building blocks into macromolecules: proteins and nucleic acids 3 Packaged into protocells a Membranes packaging lipids that also have and maintain their own internal chemistry 4 Begin to Self-Replicate a Self-assemble, but grow faster when attached to clay Vesicles or fluid filled areas enclosed by membrane form o Can reproduce. Metabolize, and keep homeostasis o Form by lipids introduced in water, hydrophobic tails form a lipid bilayer o Form external metabolism RNA is in first life form instead of DNA o Ribozymes can make RNA if supplied with nucleotides o Pass on genetics by replicating and producing protocells The Archaean Eon Prokaryote- unicellular organisms containing a capsule, cell wall, plasma membrane, cytoplasm, and flagella; but no membrane bound organelles Stromatolites-layered rocks forming by prokaryotes binding thin films of sediment o Found in shallow marine bays Cyanobacteria’s ancestor begins to photosynthesize o Oxygen reacts with water forming iron oxide, sediment, oxygen dissolves into water and saturates it, then an atmosphere begins to form o Oxygen revolution leads to first major extinction, 90% of all anaerobic organisms die (oxygen is toxic to them) Proterozoic Eon Edicarian Era Single celled eukaryotes o Had cytoplasmic membrane, endoplasmic reticulum, ribosomes, nucleus, nucleolus, nuclear membrane, Golgi apparatus, mitochondria and/or chloroplast o Endosymbiont Theory-mitochondria and chloroplasts were absorbed by eukaryotic cell not all eukaryotes have chloroplasts Support for Theory: 1 Inner membranes have enzymes and transport systems similar to prokaryotes 2 Replicate by splitting process similar to prokaryotes, circular DNA without histones or proteins 3 Have cellular machinery to translate and transcribe DNA 4 Size, RNA sequence, and sensitivity similar to prokaryotic ribosomes Multicellular Eukaryotes o Evolution of eukaryotic cells allowed for greater range of unicellular forms o Second wave of diversity occurred when multicellularity evolved giving rise to algae, plants, fungi, and animals Multicellular Organisms o Algae form 1,200,000,000 years ago o Edicarian biota assemble larger more diverse soft bodied organisms that lived 535,000,000-600,000,000 years ago (life started in water because it’s a more stable environment: hard to heat, organisms need water to live and none had developed mucus coating of skin to survive terrestrial life yet) Phanerozoic Eon Paleozoic Era Cambrian Explosion (535,000,000-525,000,000 years ago)- over 10 million years: sponges, cnidarians, and molluscs o Predators begin to make first appearance Ordovician (450,000,000)- colonization of land by fungi, plants, and arthropods Devonian (365,000,000)- tetrapods begin to appear o Includes amphibians, reptiles, and mammals o Mammals evolved and have lower jaw with one bone; malleus, incus, and stapes; and different teeth types Permian Extinction (251,000,000) o 96% of marine species extinct and 8-27 orders of insects destroyed o 1.6 million kilometers covered by lava, raised temperature 6 degrees Celsius, led to ocean acidification, anaerobic bacteria thrives, aerobic organisms decline Pangaea-supercontinent 250,000,000 years ago, destroyed much ocean habitat by making basins deeper o Promotes allopatric speciation(geographic speciation as populations became isolated from each other preventing genetic swapping) Mesozoic Era Cretaceous Extinction (65,000,000 years ago)- wiped out half of marine species, most land animals and plants (all dinosaurs except birds) o Happened by asteroid or comet o Takes 5-10 million years to recover diversity after mass extinctions Cenozoic Era Humans diverge from monkeys 6,000,000 years ago Evolutional Change Microevolution- evolving above the species level Example: mass extinction affecting biodiversity and key adaptations through speciation Adaptive Radiation Evolutionary change over time which new species are formed with adaptations to fill different niches Regional- new organisms find a new habitat and face little competition 65,500,000 years ago mammals began to diversify and grow to fill roles left behind by dinosaurs Rise of photosynthetic prokaryotes, evolution of large predators (Cambrian), colonization of land all led to adaptive radiation Changes In Genes And Body Heterochrony-evolutional change in timing of developmental events o Examples: loss of hind limbs in whales due to slow growth, creation of wings in bats by accelerated finger growth Paedomorphosis-reproductive organs grow faster than other organs causing juvenile body types with reproductive capabilities Homeotic genes- regulatory genes that determine where things grow Changes in nucleotide sequences in developmental genes affect function of the gene Regulation of gene expression can cause evolutionary changes also Evolution Is NOT Goal Oriented Darwin (Descent and Modification)-complex structures develop over time from ancestral structures Chapter 26: Phylogeny And the Tree of Life Phylogeny- hierarchal structure showing how every life form is related through evolution Systematics-classifying organisms and determining their evolutionary relationships o Molecular systematics- using genetic data to infer evolutionary relationships o Problems: 1 So many different ways to organize a tree based on large amounts of data sets and genomes for each species, various combinations Phylogenies Show Evolutionary Relationships Taxonomy- how organisms are classified and named Binomial Nomenclature th 18 century Carolus Linnaeus published a taxonomic system based on resemblances between species A two part scientific name was formed: 1 Genus-group in which species belongs 2 Species Hierarchal Classification Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species Taxon- taxonomic unit at any level of hierarchy Linking Classification and Phylogeny Phylogenetic tree-branching diagram that represents the evolutionary history of a group of organisms Problems: 1) A species gets placed in a genus not most closely related, over evolution a species loses key feature shared by relatives 2 Tells us nothing about evolutionary relationships between groups Sub Levels of Phylogenetic Trees: o Branch points- divergence of two evolutionary lineages from a common ancestor o Sister taxa- groups of organisms that share an immediate common ancestor o Outgroup- relative taxon, but not on the same branch point o Rooted- ancestral lineage found at beginning branch point o Basal taxon- lineage diverging early in a group, lies on branch originating from shared ancestor, doesn’t mean it hasn’t evolved o Polytomy- branch point in which more than two descendant groups emerge Systematic Trees- class, order, etc. but NO ancestor just groups of taxonomy What We Can and Cannot Learn From Phylogenetic Trees 1 Intended to show evolutionary descent, not phenotypic similarity 2 Branching sequence doesn’t always show actual ages of particular species 3 Do not assume taxon on tree evolved from taxon next to it Phylogenies Inferred From Morphological And Molecular Data Homologies-phenotypic and genotypic similarities due to shared ancestry o Degree of homology-how closely genomes are related Analogy- similarity between organisms due to convergent evolution o Due to natural selection and environments producing similar adaptations in organisms from different evolutionary lineages o Look similar but internal anatomy is different Homoplasies- independently developed analogous structures Molecular Homologies- align DNA sequences to see if species are closely or distantly related Shared Characters Help Construct Phylogenetic Trees Cladistics- common ancestry used to classify organisms o Clade-ancestral species and ALL its descendants 1 Monophyletic CLADE- ancestral species and ALL its descendants 2 Paraphyletic GROUP- ancestral species and some descendants 3 Polyphyletic GROUP- distantly related species but NOT recent ancestor Shared Ancestral And Derived Characters Shared ancestral character- originates in the ancestor of the taxon Shared Derived Character- not found in ancestor but found in clade o Outgroup- group or species from evolutionary lineage that diverged before other in lineage Phylogenetic Trees With Proportional Branch Lengths Just because a group evolved over a larger period of time does not mean it hasn’t evolved Max Parisomy and Max Likelihood Max Parisomy-investigate simplest explanation consistent with facts Max Likelihood- given set of DNA based on probability on how DNA sequence changes over time Genomes Document Organism’s Evolutionary History DNA changes relatively slowly and can be used for investigating relationships in taxa 100,000,000 years ago Mitochondrial DNA evolves rapidly and is used to explore recent evolutionary relationships such as species Gene Duplications And Gene Families Duplication increases the number of genes in genome providing more opportunity for evolutionary change Orthologous genes- homology occurs between genes found in different species o Only diverge after speciation Paralogous genes- homology results from gene duplication with the same system Genome Evolution 1 Orthologous genes are shared by lineage that diverged long ago 2 Number of genes in a species doesn’t increase through duplication at same rate as phenotypic complexity Molecular Clocks Measuring absolute time of evolutionary changes based on observation that some genes and genomes evolve at constant rates Number of nucleotide substitutions in orthologous genes is proportional to time elapsed since they diverged from ancestor Paralogous- number of substitutions is proportional to time since ancestral gene was duplicated New Data Changes Tree of Life Horizontal gene transfer-genes transferred from one genome to another through: 1 Exchange of transposable elements and plasmids 2 Viral Infection 3 Fusions of organisms CHAPTER 27: BACTERIA AND ARCHAEA Structural and Functional Adaptations Contributing To Prokaryotic Success Prokaryotes thrive almost everywhere including places too acidic, salty, cold, or hot for most other organisms o Microscopic o Divided into two domains: Bacteria and Archaea First organisms to inhabit Earth were prokaryotes o Unicellular o Sphere, rod shaped, spiral o .5 micrometers to 5 micrometers with largest being 750 micrometers Cell Surface Structures Cell wall- maintains cell’s shape, protects cell, and prevents it from bursting in a hypotonic environment, but CAN’T keep it from shrinking in a hypertonic environment o High sugar or salt slows down bacteria reproduction o Bacteria cell wall contains peptidoglycan (polymer of modified sugars cross linked with polypeptides) o Archaea’s cell wall contains polysaccharide and proteins, but NO peptidoglycan o Eukaryotes don’t all have a cell wall, but those that do are made of chitin or cellulose (plants) No nucleus but DNA is stored in nucleoid (no membrane) Gram Stain- used to categorize bacterial species by differences in their cell walls 1 Stain samples with crystal violet dye and iodine 2 Rinse with alcohol 3 Stained with red dye Gram positive- simple walls and lots of peptidoglycan, reacts with stain Gram negative- more complex walls with outer membrane containing lipopolysaccharides and less peptidoglycan which is found between the walls of lipopolysaccharides o More likely to be antibiotic resistant o Many antibiotics target peptidoglycan and damage bacterial cell walls Capsule- polysaccharide (protein layer) covers many prokaryotes cell walls o Condensed or diffused Fimbriae- hair like projections that allow prokaryotes to stick to other individuals in a colony or other substrates Sex Pilus- pulls cells together prior to DNA transfer Plasmid- small DNA molecule within cell physically separated from chromosomal DNA and can replicate independently Endospore- forms when cells lack nutrients, resistant cell dehydrated and containing only DNA, can last up to centuries in poor environments Motility Taxis- movement toward or away from stimulus o Chemotaxis- movement toward or away from chemical stimulus o Propelled by flagella scattered on their surface or concentrated at one or both ends Flagella found in prokaryotes, archaea, and eukaryotes is composed of different proteins and therefore evolved separately (convergent evolution) 1 Motor Unit sits in cell wall 2 Hook attaches to filament 3 Filament moves Internal Organization and DNA Have organization (mitochondria and chloroplasts which are prokaryotes prove this) some specialized membranes by folding of the plasma membrane o Thylakoid membrane and respiratory membrane are examples Prokaryotic genome has less DNA then eukaryotic genome o Prokaryotes have circular DNA o Eukaryotes have linear DNA Prokaryotic ribosomes are smaller and differ in RNA and protein content Reproduction and Adaptation Good conditions they reproduce 1-3 hours Key Features of Prokaryotic Reproduction: o Small o Reproduce by binary fission o Short generation times o More chances for mutation and adaptation Mutation rates from binary fission low, but due to rapid reproduction mutations accumulate High diversity from mutation allows for rapid evolution Reproduction, Mutation, Recombination, Promotes Diversity Mutations increase genetic diversity quickly in a species with large numbers and short lifespans Lenski put .1mL of each of 12 populations of E. Coli bacteria in 9.9mL of growth medium with low levels of glucose and other resources o Conclusion: populations accumulated beneficial mutations for 20,000 generations allowing for rapid adaptive evolution Genetic Recombination Combining DNA from two sources; happens in prokaryotes by transformation, transduction, and conjugation Transformation- phenotype or genotype of cell altered by intake of foreign DNA o Recombinant-chromosome contains DNA from two different cells Horizontal gene transfer- movement of genes from one organism to another, not members of the same species o Two types of Transformation: 1 Natural- foreign DNA attaches to host DNA receptor using DNA translocase to enter cell 2 Artificial: Chemical mediated- cold cells conditioned in calcium chloride, suddenly exposed to heat, cell membrane becomes permeable letting DNA in Electroporation- expose cell to electric field creating pores and allowing DNA in Transduction- phages carry prokaryotic genes from one host to another o Lysogenic phase- viral phage DNA stays dormant in host, lysogenic cycle is then promoted by an outside factor such as temperature, viral phage lets the host cell make its DNA, causes lysis of the host cell, spreads to other cells Conjugation- DNA transferred between two prokaryotic cells that are temporarily joined 1 Donor cell attaches to recipient by pilus 2 Pilus retracts pulling cells together 3 Mating Bridge- donor cells transfers DNA to recipient o F-Factor- part of DNA allowing ability to form pili and donate DNA Cells containing f plasmid function as DNA donors during conjugation Those without the f-factor are recipients of the DNA F factor is transferrable through conjugation R-Plasmids carry genes for antibiotic resistance and can pass DNA on by conjugation Diverse Nutritional and Metabolic Adaptations Evolve in Prokaryotes Prokaryotes can be categorized by how they obtain carbon and energy o Phototrophs get energy from light o Chemotrophs get energy from chemicals o Autotrophs use carbon to make their own energy o Heterotrophs require organic nutrients to make other organic compounds Obligate Aerobes- use oxygen for cellular respiration Obligate Anaerobes- poisoned by oxygen use fermentation o Anaerobic respiration- substances other than oxygen used as a final electron acceptor in ETC Facultative Anaerobes- survive with or without oxygen Nitrogen Metabolism Nitrogen is key in producing amino acids and nucleic acids Nitrogen fixation- convert nitrogen to ammonia o Used to form amino acids Metabolic Cooperation Heterocysts- specialized cells focused on nitrogen fixation, their walls keep oxygen out o Other cells form filamentous chains to carry out photosynthesis and nitrogen fixation together Biofilms- surface coating colonies where metabolic cooperation happen o Stick cells together with polysaccharides and proteins o Signaling molecules to attract cells A Survey of Prokaryotic Diversity Archaea Extremophiles- lovers of extreme conditions o Extreme Halophiles- live in highly saline environments o Extreme Thermophiles- thrive in super, hot environments Structural and biochemical adaptations keep DNA and proteins stable at high temperatures Methanogens- release methane as a by-product of producing energy o Poisoned by oxygen Prokaryotes Play Crucial Roles In Biosphere Chemical Recycling Decomposers- chemoheterotrophic prokaryotes break down dead organisms and waste products returning them to nitrogen, carbon, etc. Prokaryotes increase availability of nitrogen, phosphorus, and potassium o Can also immobilize nutrients by using them to synthesize molecules in their own cells Ecological Interactions Symbiosis- two species living in close contact o Prokaryotes do this with larger organisms Host- larger organism Symbiont- smaller organism Mutualism- both species benefit Commensalism- one species benefits while other isn’t affected Parasitism- one species suffers as the other feeds from it o Pathogen- parasite that causes disease Prokaryotes And Humans Mutualistic bacteria like in our gut helps break down food and synthesize carbs, vitamins, etc. Pathogenic bacteria- causes sickness by producing poisons o Exotoxins- proteins secreted by bacteria and other organisms o Endotoxins- lipopolysaccharide of outer membrane of gram negative bacteria carries harmful proteins Released by the bacteria dying and the cell walls breaking down Bioremediation- use of organisms to remove pollutants from the soil, air, or water CHAPTER 32: AN OVERVIEW OF ANIMAL DIVERSITY Concept 32.1 Multicellular eukaryotes (bacteria and archaea are unicellular prokaryotes) Heterotrophic- cannot produce their own organic molecules; instead they obtain energy from sources outside their bodies: living organisms and abiotic organic material, and ingest it, digesting it inside themselves (unlike fungi which are still heterotrophic but use enzymes outside of the body to digest food and then eat it) Animals are not just vertebrates, there are invertebrate animals also Occupy every ecological niche on Earth, same goes for prokaryotes Cell Structure and Specialization Lack a cell wall (unlike fungi, plants, bacteria, and archaea); therefore they gain structural support outside of cell by proteins like collagen Animals have nervous system tissue (derived from ectoderm) and muscle tissue (mesoderm) which are unique to them o This means can actively move (voluntarily) by nervous system issuing commands to muscles o Tissues- all animals except sponges (Porifera) have cells organized into structural and functional units called tissues to perform a specific task (unlike prokaryotes, they don’t need to use osmosis to get nutrition Reproduction and Development Most animals reproduce sexually with a diploid stage usually dominating the life cycle Embryonic Development o Diploid zygote- sperm fertilizes an egg 1 Cleavage- mitotic divisions where cell doesn’t grow 2 Blastula- multicellular stage in form of a hollow ball surrounding blastocoel cavity 3 Gastrulation-one side of embryo folds in and expands filling blastocoel and forming embryonic tissues: ectoderm and endoderm Gastrula- developing stage o Larva- morphologically distinct, sexually immature form Metamorphosis- transforming animal into juvenile, not yet sexually mature Regulatory genes containing DNA sequences are called homeoboxes o Hox genes- control expression of genes influencing morphology History of Animals Origin of Multicellular Animals Choanoflagellates (found in sponges) are very similar to the closest ancestor of animals o Comparing animal and Choanoflagellates genomes show that the transition to multicellular animals involved new ways of using proteins that were encoded by genes in Choanoflagellates Evolution From A Common Ancestor Neoproterozoic Era o Edicarian Biota- soft bodied multicellular eukaryotes Molluscs, sponges, and cnidarians Neoproterozoic rocks- contain fossils of microscopic animal embryos Some predation shown by holes drilled in Cloudina Paleozoic Era o Cambrian Explosion- Arthropods, chordates, echinoderms Bilaterians- clade whose members have mouth, efficient digestive tract, and anus o Cambrian lifeforms diversified causing Edicarian to decline: 1 Predators adapted to killing soft bodied Edicarian unless they adapted protection 2 Higher oxygen- large animals with high metabolism thrive, harming other species 3 Origin of Hox genes and adding of microRNAs, evolved new body forms o Animals diversify more during Ordovician, Silurian, and Devonian periods and mass extinctions o Fishes are the first vertebrates, become predators o 450 mya arthropods move to land o 365 mya vertebrates move to land Mesozoic Era o Coral reefs form, reptiles return to water o Modification in tetrapods leads to wings o Large and small dinosaurs o Mammals (nocturnal insect eaters) o Flowering plants and insects diversify Cenozoic Era o Mass extinction o Large mammals (herbivores and predators) o Climate cools Animals Characterized By Body Plans Grade- a group of animals whose members share key biological features, but is not a monophyletic group or clade Body Plan- set of morphological and developmental traits forming a living animal o Evo-devo- interface between evolution and development o Similar bodies evolve in different lineages o Body features can be lost in evolution Symmetry Radial- cut from center, get same halves, only applies to the outside o Sessile(attached to something) or planktonic (drifting) Bilateral symmetry- right and left, front and back, head and tail, cephalization(creation of a head) o Dorsal (top), ventral (bottom), anterior (front), posterior (back) o Active movers Tissues (Eumetazoa- true body tissues) Ectoderm- covers embryo’s surface, gives way to epidermis and sometimes central nervous system Endoderm- inner germ layer; forms digestive tract lining, liver, and lungs Mesoderm- skeletal system, muscle system, coelem (coelomates) Diploblastic- animals with only ectoderm and endoderm Bilateral animals have a third layer and are Triploblastic o Third layer (mesoderm)- in between endoderm and ectoderm; forms muscles and other organs Body Cavity Fluid or air filled space between outer body wall and digestive tract 1 Coelem- (derived from mesoderm) forms and connects structures suspending internal organs (coelomates) 2 Pseudocoelem- body cavity is disconnected, formed from mesoderm and endoderm (pseudocoelomates) 3 Acoelomates- no body cavity, use diffusion o For invertebrates the fluid in the cavity acts as a hydrostatic skeleton o Prevents internal injury, enables organs to grow and move independently from outer wall Protostome and Deuterostome Development Protostome Development 1 Spiral Cleavage-planes of cell division diagonal to vertical axis (daughter cells centered over the grooves of the parent cells) Determinate Cleavage- fate of development of the embryonic cell is determined early on 2 Archenteron (tube becoming gut) is formed by solid masses of mesoderm splitting to form coelem 3 Blastopore- indentation during gastrulation leading to development of archenteron Mouth is formed from blastophore Deuterostome Development 1 Radial Cleavage- planes parallel or perpendicular to vertical axis of embryo, tiers aligned Indeterminate Cleavage- cells produced by early divisions can develop into complete embryos 2 Mesoderm buds from archenteron wall cavity and creates coelem 3 Anus formed from blastophore, mouth forms from a secondary opening o vertebrates and chordates all follow deuterostome development o invertebrates can develop protostomically and deuterostomically Animal Phylogeny Shaped By New Molecular and Morphological Data Diversification of Animals 1 All animals share a common ancestor 2 Sponges are basal animals (monophyletic) 3 Clade of animals with true tissues is called Eumetazoa. Includes all animals except sponges and a few others 4 Most animal phyla belong to Bilaterian clade 5 Three major clades of bilaterians: o Deuterostoma o Lophotrochozoa o Ecdysozoa Deuterstomia o Hemichordates (acorn worms)- gill slits, dorsal nerve cord, invertebrates o Echinoderms (sea stars) invertebrates o Chordates (vertebrates) Ecdysozoa o Nematodes and Arthropods External skeleton Ecdysis- shedding of old skeleton Lophotrochozoa o Lophophore- crown of ciliated tentacles aiding in feeding o Trocophore larva- developmental stage o Platyhelminthes, Rotifera, Ectoprocta, Brachiopodia, Mollusca, Annelida Protostome development Chapter 33: An Introduction To Invertebrates Invertebrates-animals without vertebrae, does not mean they don’t have some form of a skeleton o Aquatic invertebrates use water to counteract gravity o 95% of all known animal species are invertebrates 1 Hydrostatic skeleton: fluid filled coelom which is surrounded by muscle Can move by using fluid pressure and longitudinal muscles, thrashing movement 2 Exoskeleton: covers outside of body, used for muscle attachment Apodemes- indentations muscles can attach to o Have a ventral hollow nerve cord o Skeletons made out of calcium carbonate Phylum Porifera: Sponges Sessile and normally asymmetrical, no “true” tissues Filter feeders: 1 Ostia- pores that allow water to enter into a cavity called the spongocoel 2 Choanocytes beat their flagella to draw water from pores and out the osculum 3 Amoebocytes (use pseudopodia) take food from water and digest it Totipotent- can become other cells if needed Manufacture skeletal fibers in mesohyl: spicules or spongin Gas exchange and waste removal by diffusion Hermaphroditic- male and female gonads o Cross fertilization o Larval flagellated swimming stage Phylum Cnideria Eumatozoans, they have “true” tissues Diploblastic (endoderm and ectoderm) and radially symmetrical Gastrovascular cavity with one opening Cnidocytes- stinging cells containing an organelle called a nemocyst that when triggered releases banned threads Two body plans 1 Polyp- cylindrical in shape, sessile form that attaches aboral end to a substrate and uses tentacles to capture prey Examples: hydras and sea anemones 2 Medusa- free swimming form by drifting of contracting bell shaped body Example: jellies Clade Medusozoa Class Scyphozoa- (jellies) most time spent in medusa form Class Cubozoa- (box jellies) mainly medusa form Class Hydrozoa- (hydras, Obelias, Portuguese Man O’ War) alternate between polyp and medusa form Class Anthozoa Sea anemones and coral only found in polyp form Exoskeleton made of calcium carbonate Clade Lophotrochozoa Bilaterian with triploblastic development Protostome development: spiral cleavage and determinate cleavage, mouth forms from blastophore OR Deuterostome development: radial cleavage and indeterminate cleavage, anus forms from blastophore Gastrovascular cavity with one opening OR Alimentary canal- complete digestive system with two openings Lophophore- ciliated crown of tentacles for feeding Trocophore larva Phylum Platyhelminthes Aquatic Freeliving and parasitic species Triploblastic but acoelomates (no body cavity) Respiration involves diffusion Protonephridia- networks of tubules with ciliated structures (flame bulbs) pulling fluid from outside through branch ducts, can get rid of some nitrogenous waste Gastrovascular cavity with one opening, no circulatory system Protostome development, complex nervous system Both monoecious and dioecious Class Turbellaria (Flatworms) o Most marine, some freshwater and terrestrial o Predators or scavengers o Example: planaria Class Trematoda (Flukes) o Parasites use two suckers to attach to host, have an alimentary canal o Shistosoma mansoni adults live in human intestine, eggs found in feces, larvae find snail and reproduce asexually (intermediate host), those larvae penetrate skin and mature in humans (final host) o Evade detection by flaky cuticle and mimic proteins of hosts, manipulating their immune system Class Cestoda (Tapeworms) o Adults live and reproduce in vertebrates intestines, eggs found in water or food of intermediate host, eaten, forms cysts in muscles, muscle tissue eaten by final host o Scolex (anterior) armed with suckers and hooks o No mouth, absorb nutrients from host’s intestine o Proglottids on posterior loaded with eggs Phylum Rotifera Aquatic Alimentary canal- digestive tube, mouth, and anus Pseudocoelomate, hydrostatic skeleton Lophophore, trophi (jaws) grind food Reproduce sexually in high populations or by parthenogenesis (females producing more females from unfertilized eggs) Lophophorates Lophophore- horseshoe shaped, feeding organ with ciliated tentacles No cephalization, u shaped alimentary canal True coelom completely lined with mesoderm Phylum Ectoprocta: o Colonial animals who resemble plants exteriorly o Exoskeleton, reef builders o Gas exchange across Lophophore, no circulatory system Phylum Phoronida o No heart, vessels do peristalsis o Mesoderm derived closed circulatory system Phylum Brachiopodia o One or more hearts, open circulatory system o Shells dorsal and ventral Phylum Nemertea Bilateral symmetry, protostomic development, triploblastic, small fluid filled sac was potentially a reduced coelom Chemoreceptors and photoreceptors, complex nervous system Proboscis- used to get prey, operate by hydraulics Alimentary canal and closed circulatory system No heart, diffusion Phylum Mollusca Snails, oysters, octopus, squids, clams, slugs Soft bodied, some have internal or external shells, others no shell 3 Parts: 1 Foot 2 Visceral Mass- most of internal organs 3 Mantle- tissue covers visceral mass, secretes shell Mantle cavity- extension of mantle, water filled chamber with: gills, anus, excretory pores Radula- picks up food, rough tongue Trocophore larval stage Class Polyplacophora (Chitons) o No cephalization, 8 plated shell, marine, foot to move, radula Class Gastropoda (Snails and Slugs) o Marine, freshwater, and land o Cephalization o Shell (snails), no shell (slugs) o Ciliated foot to move o Radula, torsion- anus and mantle are above head Class Bivalvia (clams, mussels, scallops, oysters) o Aquatic o Paired gills o No radula o Two sided shell, adductor muscles Class Cephalopoda (Squids, Octopi, Nautiluses) o Marine o Head surrounded by tentacles o Internal shell (squid=pen), external, or none o Radula o Jet propulsion by excurrent siphon pushing out water o Closed circulatory system o Poison in saliva, carnivorous with beak Phylum Annelida Bilateral symmetry, protostome development, triploblastic, true coelomate, diffusion, closed circulatory system Simple brain in anterior, ganglia in segments, chemoreceptors, photoreceptors, sense moisture Hermaphroditic, sexual reproduction Setae and parapodia used to move Class Polychaeta o Marine o Blood vessels function as gills o Paddlelike parapodia work as gills and to move Have chitonous setae o Jaws and sensory organs well developed Class Hirudinea (Leeches) o Marine, freshwater, and moist land habitats o Parasite sucks on other organisms blood o Blade-like jaws, use anticoagulant hirudin o Also use anesthetic to numb site of incision Class Obligochaeta (Earthworms) o Alimentary canal with mouth and anus o Repeated segments called septa, each with excretory and locomotive organs o Coelom o Hydrostatic skeleton, longitudinal, and circular muscles o Chaetae to anchor o Matanephridia, ganglia, closed circulatory system o Hermaphroditic, dioecious, fragmentation Clade Ecdysozoa Covered by cuticle Undergo ecdysis or molting Phylum Nematoda (Roundworms) One millimeter to one meter Sheds cuticle as it grows Alimentary canal, no circulatory system, pseudocoelom Longitudinal muscle, well developed nervous system, pharynx Bilateral symmetry, protostomic development Reproduce sexually, internal fertilization Free living decomposers and parasites (hookworms) o Plant parasites can make root cells grow to them and provide them nutrients by producing molecules o Trichenella controls muscle cell gene expression to house it, and releases signals attracting blood cells to provide it with nutrients Phylum Arthropoda Bilateral symmetry, protostomic development, triploblastic, coelomate Exoskeleton, segmented body, jointed appendages o Has two pairs of Hox genes Respiratory organs (land: tracheal systems; water: gills) Open circulatory system Sensory organs: olfactory, antennae: touch and smell Well-developed brain and nervous system Complex social structure Sexual reproduction Hemocoel- open circulatory system with fluid called hemolymph is propelled by heart to short arteries and to sinuses around muscles and organs Subphylum Chelicerata o Sea spiders, horseshoe crabs, scorpions, ticks, mites, spiders o Chelicerae- pincers or fangs, claw-like feeding appendages o Cephalothorax (head and neck fused together) and abdomen o Simple eyes o Earliest were eurypterids (water scorpions) ranging three meters long, now extinct o Class Arachnida- scorpions, spiders, ticks, mites Six pairs of appendages: chelicerae, pedipalps (defense and reproduction, feeding) and four pairs of walking legs Book lungs- stacked plate like structures in an internal chamber Subphylum Myriapoda o Millipedes and centipedes o Terrestrial o Head has antennae and three modified mouthpart appendages: jaw-like mandibles o Millipedes have trunk segments formed by two fused segments with two pairs of legs Eat decaying plant matter o Centipedes have one pair of legs on each trunk segment Carnivores with poisonous claws on first trunk segment Subphylum Crustacea o Crabs, lobsters, shrimp, barnacles, etc. o Marine, land, and freshwater environments o Two pairs of antennae o Three or more mandibles o Legs on thorax and abdomen o Small gas exchange on cuticle; large gills are used o Males and females; aquatic have larval stage 1 Isopods (pill bugs and wood lice) 2 Decapods (have carapace, mostly marine) 3 Copepods- grazers on algae and predators Insects Abdomen, thorax, head, heart, open circulatory system, cerebral ganglion, Malpighian tubules, tracheal tubules, nerve cords Wings extension of cuticle on dorsal side of thorax Diverged by what they ate Incomplete metamorphosis- young (nymphs) resemble adults but smaller, molt until it reaches full size Complete metamorphosis- larval stage, pupil stage, adult Dioecious Females have a sperm pouch called spermathecal Carries of disease, pollinators, food sources in some countries, competitors for human food Clade Deuterostomia Bilaterian, deuterostome development (radial and indeterminate cleavage), triploblastic Phylum Echinodermata Slow moving or sessile marine animals Thin epidermis over hard calcareous plates Water vascular- hydraulic canals branch into tube feet to help organism move and feed Dioecious Larvae have bilateral symmetry, adults radial Class Asteroidea (Sea Stars and Sea Daisies) arms come from central disk tube feet used to move: attach and detach from substrates by secreting adhesive and then chemical to unbind adhesive spit out stomach through mouth and use digestive enzymes on prey then brings back stomach regrow lost arms Class Ophiuroidea (Brittle Stars) Distinct central disk and long flexible arms they use to move Tube foot lacks flattened disks but secretes adhesive Suspension feeder, predators, scavengers Class Echinoidea (Sea Urchins and Sand Dollars) No arms, five rows of tube feet Muscles pivot on long spines for movement and protection Mouth on underside with complex jaw Sea urchins: spherical, sand dollars: flat Class Crinoidea (Sea Lilies and Feather Stars) Sea lilies attached to substrate by stalk Feather stars use long arms to move Suspension feed Class Holothuroidea (Sea Cucumbers) Lack spines, reduced exoskeleton Five rows of tube feet around mouth, act as feeding tentacles Chapter 34: Origin And Evolution Of Vertebrates Phylum Chordata Bilateral symmetry, deuterostome development, not all groups are vertebrates (invertebrates: cephalochordate, urochordata, and myxini) Four Key Characteristics: 1. Notochord- first skeletal element, not a backbone, cartilaginous and flexible, place for muscles to attach 2. Dorsal Hollow Nerve Cord- derived from ectoderm, not protected by notochord 3. Pharyngeal gill slits 4. Post Anal Tail o All of these characteristics need to be present at the same time in order for an animal to be considered a chordate o Notochord and dorsal hollow never cord are the only two characteristics unique to chordates o Invertebrates have a ventral hollow nerve cord Early Chordate Evolution Ancestral chordates are thought to resemble lancelets Duplication of Hox genes (body plan), make body more complicated, one’s for brain expressed in nerve cord tip of lancelets o First time duplication of Hox genes happened was in the arthropods during the Cambrian explosion Tunicate genome shows o Genes associated with the heart and thyroid are found in all chordates o Ones associated with transmission of nerve impulses are unique to vertebrates Subphylum Cephalachordata (Lancelets) o Basal chordates o Marine suspension feeders o Invertebrates Subphylum Urochordata (Tunicates) o Marine suspension feeders o Larvae exhibit four derived characteristics of chordates o Invertebrates Craniates Cephalization: skull, brain, eyes, and other sensory organs Duplication of Hox genes forming two clusters verses one in lancelets and tunicates Have a neural crest which is a cluster of cells near a closed neural tube that form bones and cartilage of skull, arises from ectoderm, invertebrates have shown that you don’t need a neural crest to have a nervous system Higher metabolism and more muscular than tunicates and lancelets Heart with two chambers, red blood cells with hemoglobin and kidneys Class Myxini (Hagfishes) o End of Cambrian Era, feed on carcasses, jawless o Flexible cartilage (invertebrate) can tie itself in a knot and secretes gelatinous mucus when threatened o Has a complicated digestive system Vertebrates Genes producing transcription factors and signaling molecules are doubled o Nervous system, skeleton, development of skull, and a backbone with vertebrae Three Parts Of Brain: 1. Forebrain- olfaction and chemical ques 2. Midbrain- vision 3. Hindbrain- respiration and metabolism Class Petromyxontida (Lampreys) o Oldest vertebrates, no jaw so instead they use hooks to attach to an organism and feed on their blood, have an anticoagulant Cartilage made of proteins (not collagen), sheath around notochord, cartilaginous extensions extend from it and close around the nerve cord Origins Of Bones And Teeth Mineralization originated with vertebrate mouthparts Teeth associated with jaws, hardest substance in body Endoskeleton mineralized much later Structures in order from least to most minerals: cartilage, bone, teeth Invertebrates used calcium carbonate to mineralize structures, calcium phosphate is used in vertebrates Calcium phosphate is much more stable in acidic conditions, vertebrates need this because muscle movement and metabolism are acidic, needed for evolution into more active lifestyle Gnathostomes Shared Derived Characters: Jaws evolved from skeletal rods around pharyngeal gill slits moving forward o Developed to pull more oxygen in, which in turn pulled more food in; makes predators more active o Jaws were also found in arthropods Enlarged forebrain which enhanced smell and vision Four sets of Hox genes Aquatic have lateral line systems, sense vibrations Paired appendages Class Chondrichthyes (Sharks, Skates, Rays) Cartilaginous fish, paired appendages: fins fixed to side of animals body to provide lift (pectoral and pelvic fins) Higher metabolic rates so they must continuously swim to get enough oxygen for metabolism Lower metabolic sharks don’t need to continuously swim Have dermadenticles No eardrums, olfaction, good at detecting electric fields Oviparous- lay eggs hatch outside of mother’s body Ovoviviparous- fertilized eggs hatched within uterus, then birthed Superclass Osteichthyes Class Actinopterygii (Ray Finned Fishes) o True bone making up endoskeleton o 31,000-56,000 are fish in vertebrate group o Higher metabolism (carry and make skeleton) o One opercular cover, more gills placed together to support a higher metabolism by maximizing oxygen o Occupy every ecological niche where water is present Class Sarcopterygii (Lobe Finned Fishes) o Ancestors of tetrapods (move from water to land), lead to amphibians o More skeletal structures to hold fins (humerous) o Coelacanths and lungfishes o Slowly leads to formation of radius and ulna in amphibians Tetrapods Class Amphibia Jaws and paired appendages become thicker and more dense to counteract gravity Larval stage aquatic and eggs laid in water Live in extremely humid environments because thin skin to respire dries out easily (cutaneous respiration) Order Urodela (Salamanders) o Aquatic and land habitats o Tail o Paedomorphosis Order Anura (Frogs) o Use hind legs to jump o Catch prey with sticky tongue o Skin glands contain poisonous or distasteful chemicals, camouflage Order Apoda (Caecilians) o Resemble earthworms, burrow in moist soil Amniotes Amniotic egg 1. Amnion- respiration 2. Allantois- collects waste 3. Chorion- protection by fluid inside to cushion embryo o Opened ability for vertebrates to colonize land o Always present albumin (proteins) and yolk sac (nutrients) o Shell (not always hard) not closed, egg exchanges air with environment, can drown in water Class Reptilia o Tuataras, lizards, snakes, crocodilians, birds, extinct dinosaurs o Scales for waterproofing, lipids in skin to keep in moisture o Ectothermic except birds, temperature drops metabolic rate drops o Temperature dependent sex determination in eggs Aves (Birds) o Endothermic- higher metabolism due to use of energy to regulate inside temperature separate of outside o Second time flight evolved, the first time in Pterosaurs o Arms adapted into wings o Wings are the only anatomical feature necessary to fly, hollow bones not necessary (flies and bats are proof) o Feathers evolved for insulation Mammals Shared Derived Characteristics Widest variety of size and body types Mammary glands produce milk Differentiated teeth (molars, pre molars, canines, incisors) Lower jaw consists of a single bone Endothermic Presence of hair in at least one stage of life cycle Third evolution of flight in bats Secondary evolution of some mammals back to aquatic life Quadrate and articular bones become incus and malleus for hearing vibrations in air o Jaw joint- dentary and squamosal Monotremes Australia and New Guinea: consists of four spiny anteaters and one platypus Lay eggs, produce milk but have no nipples so it’s secreted by a gland on their belly Marsupials Kangaroos, opossums, and koalas Produce milk and excretion through nipples, hair Viviparous, placental birth Babies underdeveloped when born, kept in maternal pouch called the marsupium Eutherians Placental mammals Chapter 40: Basic Principles of Animal Form and Function Anatomy- biological form, naming body structures Physiology- biological function, how structures work together o Comparative study shows that form and function are closely related Animal Form and Function Are Correlated At All Levels of Organization Evolution of Animal Size and Shape Physical laws can constrain animal form o Size and shape affect how an organism interacts with their environment o Body plan of animal programmed by genome Hox genes lay out body plan, genetic material dictates what you are o Larger you become diffusion is limited, need organ systems to help facilitate diffusion: respiratory and circulatory system Muscles must be a bigger fraction of body mass in larger animals and they need thicker skeletons Exchange With Environment Nutrients, waste products, and gases are exchanged across cell membranes Size (cell layers and thickness) get’s bigger, organism develops organs: o Digestive system nutrients dissolve across intestine to circulatory system to lymphatic system o Need a respiratory system also o Still rely on diffusion taking place in their capillaries o Excretory system gets rid of metabolic waste (urine) Advantages of complex animals, helps them maintain homeostasis on land: controlled release and storage of energy by the digestive system, advanced sensory organs, skeletons for protection The challenge they face is it’s harder to exchange with the environment Simple animals one cell layer thick can just diffuse with the environment (planaria, bacteria, etc.) Hierarchal Organization of Body Plans Cells, tissues, organs, organ systems Tissue- a group of specialized cells, can belong to multiple organ systems Organ- specialized group of tissues performing a function Organ System- organs working together to complete a body process Epithelial Tissue: covers the outside of and organism’s body and also lines cavities and organs 1. Stratified Squamous Epithelium Has layers, new layers form from the basal end Around areas of constant abrasion: vagina, anus, mouth, and skin 2. Cuboidal Epithelium Cube shaped, secretory cells Kidney tubules and glands 3. Simple Columnar Epithelium Large brick like cells found where secretion of abrasion happens Intestinal lining 4. Simple Squamous Epithelium Thin cells, use diffusion Blood vessels, alveoli 5. Pseudostratified Columnar Epithelium Single cell layer, different heights and positions of nuclei Respiratory tract Connective Tissue o Holds tissues and organs together o Collagenous fibers- strength and flexibility o Elastic fibers- allow tissues to stretch o Reticular fibers- join connective tissue to adjacent tissue o Macrophages-phagocytize foreign bodies and call debris o Fibroblasts-secret fibrin 1. Loose Has collagenous fibers, reticular, and elastic Holds organs and binds epithelia to tissue 2. Fibrous Collagenous fibers Tendons and ligaments 3. Bone Osteoblasts-make collagen matrix Osteons-units of matrix Central canal- holds blood vessels and nerves 4. Adipose Fat 5. Blood Composed of: plasma, erythrocytes, leukocytes, platelets 6. Cartilage Collagenous fibers in chondroitin sulfate Chondrocytes make cartilage Muscle Tissue 1. Skeletal (movement) Muscle fibers – bundles of cells Sarcomeres- contractile units Striated 2. Smooth (involuntary) Lines digestive, urinary, and arteries 3. Cardiac Combination of smooth and skeletal Sets its own rhythm Controlled by the nervous and endocrine system Nervous Tissue 1. Neurons Electric impulses come through dendrites, cell body, and to other nerve cells through the axons 2. Glia Nourish, insulate, and replenish neurons Coordination and Control Endocrine System o Hormones pass through blood and target specific cells with the right receptors o Can last minutes to hours o Controlled by the nervous system Nervous System o Nerve impulses conducted along specific pathways o Epinephrine from the endocrine system speeds up nervous system activities o Short, voluntary reactions o Invertebrates regulate speed by increasing diameter of axons o Vertebrates speed up impulses by surrounding neurons in myelin (fat) Feedback Control Maintains The Internal Environment In Many Animals Regulation Regulator- uses internal mechanisms to maintain balance despite external factors Conformer- internal condition changes as external does proportionately Animal can be both, reptiles can regulate by shivering and through moving, but are also ectothermic Homeostasis Maintaining and internal balance Mechanisms: o Set-point- maintaining a variable at a particular point o If anything changes a sensor sends a signal to the control center to regulate, response Feedback: o Negative feedback- used to maintain homeostasis, reduces reactions by controlling them o Positive feedback- amplifies a reaction continuously Homeostatic Processes For Thermoregulation Involve Form, Function, and Behavior Thermoregulation- animals maintain body temperature at a normal range Endothermy and Ectothermy Endothermic- high metabolism to keep internal temperature separate of outside environment, activity independent Ectothermic- gain heat from external sources, activity dependent, muscles moving still generate heat, no insulation o Cold blooded not a good term since if temperature rises, so does their body heat Balancing Heat Loss And Gain o Heat exchange: radiation, evaporation, conduction, convection o High temperature to low (heat travels) o Conduction- direct transfer of heat by touching o Convection- movement of heat with air o Evaporation- cannot gain heat, only lose it Integumentary System Skin: o Epidermis, dermis, hypodermis Hypodermis found in endotherms, adipose tissue Vasoconstriction- reduce blood flow in blood vessels by constricting them to keep heat closer to the core, lose heat in extremities Vasodilation- blood vessels and capillaries dilate, radiate heat to outside environment, used to cool animal Countercurrent exchange- heat is exchanged from arteries and veins as they go in different directions Endothermic invertebrates can shiver and some heat up by moving their wings Adjusting Metabolic Heat Production o Thermogenesis- vary heat production to counteract rates of heat loss Shivering or moving o Non shivering thermogenesis- hormones cause mitochondria to increase metabolism and create heat o Brown fat- neck and shoulder fat, rapid heat production Energy Requirements Are Related To Animal Size, Activity, And Environment Bioenergetics- overall flow and transformation of
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