First notes for exam 4 through 4/20
First notes for exam 4 through 4/20 BSCI 10110
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This 9 page Bundle was uploaded by Brittany Yee on Wednesday April 27, 2016. The Bundle belongs to BSCI 10110 at Kent State University taught by Dr. Mark W. Kershner in Spring 2016. Since its upload, it has received 15 views. For similar materials see Biological Diversity in Biological Sciences at Kent State University.
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Date Created: 04/27/16
FREE LIVING HETEROTROPHS 1) Amoebozoa- amoeboid protists o Unicellular heterotrophs o Locomotion- pseudopodia (false foot) Can form anywhere on the cell so they can move any direction based on where they move their pseudopodia Remember pseudopodia is also used to find food and forage Using in foraging with phagocytosis (engluf prey with pseudopodia and forms a vacuole and floods it with digestive enzymes) o The products are moved out to the cytoplasm where it can be used for growth and reproduction Broken down into predators and pathogens/parasites o Pathogen- amebic dysentery o Parasite- Naegleria fowleri- if youre swimming and you get water up your nose that has this amoeba in the water. It breaks down the brain and there is only 1 recorded survivor ever of this 2) shelled amoeboid protists o Radiolarians- protist contained in a silica shell secreted by protist o Unicellular heterotroph. Predators that prey on bacteria and other protists that fit through the holes in their shell o Crystalline structures Amoebas, radiolarians, foraminifera are amoebozoans o Foraminifera Unicellular marine heterotrophs Form shell from calcium carbonate Feed on bacteria, shell protists Benthic- bottom dwelling Radiolarians, forams, and diatoms are used to characterize past climactic conditions (temp, salinity, nutrients) o Works because individual species are correlated with specific environmental conditions o Useful tool for geologists to get a sense of what past environments looked like CILIATES (not amoeboid*) Found in all aquatic systems One of the most recently evolved protists They have many complex organelles that are associated with separating physiological and cellular processes o They have feeding organelles, organelles associating with excreting wastes, organelles associated with mitochondria, e.t.c. o The idea is that they separate their various physiological processes over a broad range of organelles Very complex group of organisms for the above reason They are characterized by using cilia for a combination of tasks associated with their existence o Cilia- line outside the cell. Are small hair-like structures used for: Locomotion Foraging cilia creates a current that draws in small particles of food They are unicellular heterotrophs o Primarily feed on small protists, bacteria, and dead organic matter Organelles include the micronucleus and the macronucleus o Micronucleus- responsible for sexual reproduction (strictly) o Macronucleus- responsible for metabolism and homeostasis All about maintaining balance within the cell BASALPROTISTS Very simple ancestral protists. They are believed to be some of the earlierst protists They strictly use a flagellum for locomotion o They crack the flagellum like a whip to move Groups of basalprotists: o 1) Diplomads- live in polluted water Giardia- an aquatic heterotroph (parasite) that live in the digestive tract and are associated with consuming water contaminated by feces o 2) Parabasilids- Trichonomas The cause of vaginitis Found in termite guts From the listed groups, you can see that basalprotists are pathogenic (disease causing) protists EUGLENAZOA Unicellular Can be autotrophs (euglena) but a vast majority of them are heterotrophs (pathogens, parasites) Pathogenic/ parasitic euglenazoa: o Trypanosomes o (Types of trypanosoma): o 1) African sleeping sickness Parasites that are passed through bites of the tsetse fly and get into human populations. The bite itself is not the problem. When the flies land on you, they defecate on you and the feces gets into wounds and into the blood stream Affects the nervous system, the kidneys, and the cardiac system o 2) Chagas disease parasite passed by saliva, feces from “kissing bugs” attacks the heart and intestines PLASMODIUM PATHOGENS 1) Apicompleya- Malaria - plasmodium species ( n% species) o Passed through anopheles mosquito o Very common. Current estimates are that there are about 250 million cases per year and a million/1.5 million deaths per year o There is a fairly consistent search for vaccines that can prevent and treat it One of the best ways in treating it right now is by long lasting insecticidal nets, which is a net that you put over your bed that is coated with an insecticide CH 30 PLANTS Plants are found in both terrestrial and aquatic habitats They are multicellular. There are no unicellular plants They have cells walls composed primarily of cellulose and polysaccharides They get their carbon and their Energy from autotrophy, heterotrophy, and mixotrophy o Autotrophs rely on photosynthesis and various chlorophylls o Heterotrophs are primarily parasitic plants They parasitize the roots of host plants and take all of the nutrients and energy from it. They take advantage of the carbon and energy that their host plant has o Mixotrophs use autotrophy and heterotrophy Pitcher plants, venus fly trap Pitcher plant: Have green so you know theyre using cholorphyll to harvest light energy. But at the same time they fill up with water in a rain bulb and fill the bulb with a liquid that attracts insects. The insects go into the bulb and cant get out and are then digested by the plant after they die Plants are also known for having a very complex life cycle. This characterizes the entire group PLANT LIFE CYCLE Alternation of generations o Found in all plants, multicellular green, red, and brown algae Diploid vs. haploid o Alternation of generations means you have one generation that’s diploid and one that’s haploid o For humans, each human has 46 chromosomes. 46 is the diploid number of chromosomes and 23 is the number of haploid chromosomes Diploid = idea that n chromosomes from mom + n chromosomes from dad where the n stages are the haploid stages (gametes) Plants have separate independent haploid/diploid life stages meiosis Gametoph(n) (n) spores yte sporangia fertilization di(2n)d sporophyte Over time there is a shift from dominant gametophyte to dominant sporophyte ORIGINS OF PLANTS Evidence suggests they are derived from the attached forms of green algae Estimated to have been formed 500 mya o 1 billion years after the first protist fossils Chara- the group that plants are estimated to have come from (from the attached forms of green algae called charophytes) Charophytes- possible ancestor to land plants (fossil evidence) *First major evolutionary transition is the movement of plants from water to land (charophyta modern land based plant) o From a free floating environment to a gravity based environment Challenges associated with this transition include structural stability based on the relationship of gravity Without the buoyancy of water for support to stand up right o This issue has been dealt with over evolutionary time by plants by natural selection favoring rigid cell walls for support (lignins and cellulose). Without rigid cell walls the plant/tree would collapse on itself Another challenge deals with the fact that water becomes limiting once youre no longer floating in water. Challenge = capturing water o Selects for development of root systems Challenge of retaining/protecting water o Selects for protective coatings like waxy cuticles found on most plants or storage in tissues and roots Nutrient uptake o Now that the plants are not in water, they need to find places to get C,N, and P from This is handled over time (not initially) by using roots and becoming nitrogen fixers Relationship with nitrogen fixers Reproduction o When you reproduce in water as algae did, the gametes can be released into water and carried to where theyre needed. The sperm were able to swim through the water and the plants relied on water for reproduction o Now that plants are not in water, they need a way for sperm to be mobile to fertilize the egg This led to pollen, which contains sperm Herbivores- organisms that eat plant tissues and seeds that are not a threat if the plant is in the water o Eventually, this led to protective seed colors o Led to spines and thorns on leafy matter o Second degree toxic compounds in plant tissue Seasonal change o When plants are in the water they are buffered to this threat o Root based plants need to adapt their life cycles for periods of dormancy (winter) and rapid growth (spring) Early plants likely evolved from aquatic charophytes (green algae) (multicellular) Bryophytes- the earliest plants o Include hornworts and liverworts BRYOPHYTES One characteristic they all have in common is that they are all non-vascular They have no way to move water and nutrients around in the organism and they have no “internal plumbing” o Means that you don’t find them far away from water because they don’t have an easy way of moving water throughout the organism Tend to find them in wet/moist habitats o They are short (they don’t grow tall) because they have no way to move water to the top of the organism. They are generally only an inch or two tall and they grow close to the ground because they cant move water and nutrients far They lack true roots o They have rhizoids- used as an anchor to hold them into place Have a little bit of an ability to absorb water like a sponge but its not much water They lack true leaves o They have leaf like spikes o Some also have a flat “leaflet” but it does not have a true leaf o They DO have a single, long, thin cell within spikes that pulls water up from the rhizoids through capillary action Bryophytes follow alternation of generations for their life cycle o Gametophyte (n)- the dominant life cycle where fertilization occurs from sperm and eggs they produce when the fertilization occurs, it produced the sporophyte stage o Sporophyte stage (2n)- is only around for a brief period Produces haploid spores which spread to the environment and new gametophytes can form from the spores o Have mobile sperm that requires water to mov to and fertilize egg Depends on the gametophyte This is why we associate them to plants that need to be found near water TYPES OF BRYOPHYTES Hornworts- have large horn like structures that grow off the top of the gametophyte, which are the sporophytes o The fertilized egg germinates o Fertilization occurs on top of the gametophyte and the spikes grow on top of the gametophyte o Gametophyte is the leaf like base o Have a symbiotic relationship with cyanobacteria Cyanobacteria is photosynthetic and nitrogen fixers Have mutualistic relationship with cyanobacteria. The hornwort gets N as ammonia and in return, the hornwort gives the bacteria structure to grow on and provides them with carbon which enhances the growth and reproduction of the cyanobacteria The ammonia is important because it acts as a fertilizer and improves reproductive success Liverworts- have a bi-lobed structure o Have small mushroom looking structures that grow off of the gametophyte that allow the sporophyte to develop there o Gametophyte is the leaf like base Across all bryophytes, the gametophyte stage is dominant and the sporophyte stage is temporary Once the sporophyte produces spores, they die and then grow back Restricted in their size because of their inability to move water far Next major evolutionary transition is the evolution of vascularization and internal plumbing. All non-bryophyte plants have some form of vascularization and are referred to as the tracheophytes TRACHEOPHTYES All remaining plants that have vascularization and plumbing Vascularization in shoots/stems, roots, and leaves o Vascularization allows for movement of water, minerals, minerals, nutrients (sugars, N, and P) and is also important in moving hormones around to prepare for various life changes Any plant has 2 parts to its vascular system o The above and below ground portions o Within the above ground portion is a mix of vascular types of specialized cells and tissues Xylem- dead cells with thick walls Only moves water and minerals Only moves the water and minerals upwards Comes in via roots and is sent up the rest of the plant and is distributed to all plant tissues via the xylem When the water and nutrients being carried by the xylem hits the leaves, some water is lost through transpiration – gas exchange for the plant o Consequence of living in a land based environment o Transpiration is gas exchange with the environment which results in a loss of water and minerals. This is where the stomata becomes important Stomata- prevents significant water loss because of transpiration Are mouth- like structure on leaves o When theyre open, allows for gas exchange Gas exchange directly benefits photosynthesis which moves food for the plant o Take up carbon dioxide and release/ lose oxygen and water o When theyre closed, they reduce water loss Work with waxy cuticle- which reduces water loss Without the stomata, photosynthesis would not be possible o Sugars and nurtirents need to be distributed throughout the plant Phloem does this (this is the second major tissue type. The first is the xylem) takes sugars, hormones, etc from leaves and moves them throughout the plant as opposed to xylem, phloem is multi-directional vascularization means that plants can grow taller, live away from water, store water, and take water up from the soil because they have a system to move the necessary things around (the sporophyte stage is dominant now) TYPES OF TRACHEOPHYTES lycophytes- “club mosses” o sporophyte is larger and more permanent than gametophyte (sporophyte is dominant) o are NOT bryophytes, and not a true moss o have mobile sperm and require wet/moist habitats o are vascularized can get up to 5-6 inches tall o are limited because of the sperm Pteridophytes- include ferns, whisk ferns, horse tails (these are the ancestral groups) o Whisk ferns- have no true leaves and are thus not true ferns Sporophyte is dominant, gametophyte is temporary Mobile sperm wet habitats Whisk fern sporophytes lack leaves and are photosynthetic o Horsetails- same as above Lost true leaves secondarily through evolutionary time Are seedless vascular plants with hollow jointed stems o Ferns- can grow in shallower environments than ferns and whisk tails can because they have shallow root systems Can grow in drier places but they still have mobile sperm which means they can only reproduce in wet habitats or places with a lot of atmospheric moisture Their life cycle Fern sporophytes are photosynthetic, vascular, and multicellular They are not seed bearing Produce haploid spores via meiosis in sporangia Broader range of environments because they can pull water from the environment Mobile sperm with flagella so they are limited to environments near water for the sperm to swim CH 31 SEEDED PLANTS SEEDS Major evolutionary transition Gymnosperms- conifers, ginko, cycads, gnetophytes All plants prior to gymnosperms used spores to reproduce “naked seeds”- no fruit tissue surrounding the seeds o Do not come from flowers Hard outer covering DIVERSITY Cycads- tropical o Have male and female “cones” o *cones are common to all gymnosperms Cones contain male or female gametophytes Male sperm is large and can be up to 0.5mm (worlds largest sperm) Female eggs (ovule) o Gametophytes- dry, desert habitats NOT mobile sperm so they don’t depend on water for fertilization of ovules Gametophytes are commonly used in pharmaceuticals o Welwitschia Mrebilis Namib Desert Thousands of years old o Ephedra- commonly used in pharmaceuticals GINKOPHYTES Trees (first trees we’ve discussed) Broad habitat diversity historically but are completely extinct o Very dry very wet habitats Extinct in the wild but there is one ornamental species remaining o Ginko bilobia Male and female trees- either only male cones or only female cones CONIFERS Pines, spruces, redwoods, cypresses, cedars, etc.. Broad habitat diversity as well o Very dry very wet Broad diversity o Tallest/largest living organisms on earth are conifers Tallest-redwoods Largest- sequias (girth) Are the oldest non-microorganisms o Bristlecone pines- 4,000 (almost 5,000) years old in some areas GYMNOSPERM CHARACTERISTICS Very high habitat diversity o Dry and wet Sporophyte- is the dominant life stage (larger, more permanent) o Tiny and temporary gametophyte stage All share male and female cones Adapted to extreme conditions o No motile sperm o “needles”- leaves Low surface area so they lose less water during photosynthesis o Low density of stomata They open and close for gas exchange for photosynthesis Fewer stomata means less water loss during photosynthesis o They have a thick, waxy cuticle to help reduce water loss GYMNOSPERM REPRODUCTION Water is NOT required for reproduction and sperm are non motile Rely on wind to move pollen (the male gametophyte containing sperm) from male cones to female cones If pollen meets a female cone (eggs) o Fertilization- seed formation (diploid) o Embryo- seed leaves o Endosperm- carbohydrates serve as energy for the seed during germination FINAL EVOLUTIONARY TRANSITION Fruits/flowers- angiosperms o 150 million years old o 275,000 species o Angiosperms- “vessel seeds” Fertilized egg/ovule is enclosed in diploid tissue (fruit or flower) o Why flowering fruit? Very energy intensive Because they are very energy expensive to make More attractive to pollinators more seed pollination Pollinators make pollen Pollen meeting egg = fertilization and fruit seed is produced Because pollination is so important to plants, it has faced a lot of selective pressure Flowers have evolved colors, nectar, odors, location of flowers on the plant, etc Pollen gets attached to pollinator and moved to another plant o Stigma- where pollen is deposited (female) o Anther- pollen production o Each pollen has 2 sperm. One breaks down wall with the egg and the second fertilizes the egg SEED ADVANTAGES Two major seed elements: o 1) embryo + seed leaves (cotyledons) Leaves allow for early photosynthesis o 2) endosperm Carbohydrates serve as energy reserves for the seed during germination Hard outer covering o Can handle environmental variability; avoid seed predation Capable of dormancy o Can wait until growing conditions are right Range of dispersal modes o Increases the likelihood of reaching favorable habitats
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