Bio 110 Finals Study Guide
Bio 110 Finals Study Guide BIOL110
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This 14 page Study Guide was uploaded by Abby Shepherd on Sunday December 13, 2015. The Study Guide belongs to BIOL110 at Purdue University taught by Dr. Anderson in Summer 2015. Since its upload, it has received 320 views. For similar materials see General Biology in Biology at Purdue University.
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Date Created: 12/13/15
Biology 110 Finals Study Guide Section 1-3: finals questions will come directly from the 3 previous tests - see my quizlet flashcards that include ALL questions from the first three tests with the answers! - https://quizlet.com/_1u6kw3 Section 4 material (after the last test): Lecture 11/19 Conservation Biology Levels of Biodiversity Genetic diversity: genes contained within an individual, within a population, and between populations of same species o High genetic diversity makes a species more likely to be able to adapt to environmental change Makes adaptation to environmental change possible Decrease means species is less likely to be able to adapt Example: cats have many different breeds (genetic diversity), but are all the same species Species diversity: the different species in eco system or bio sphere o Endangered species: in danger of extinction throughout all or a significant portion of its range o Threatened species: considered likely to become endangered in the near future 12% of bird species 21% of mammal species o Extinct species: never to be found again; can be locally or globally extinct Extirpated: gone from a local area but not from the planet Ecosystem diversity: different ecosystems in the biosphere Eco system services Why should we care about ecosystems and biodiversity loss? Reasons: o Biophilia: our sense of connection to nature and all life Edward Wilson coined this term Term that cannot be "measured" o Religious belief and moral argument that other species are entitled to life o Concern for future human generations Generations of the future would not have a nice earth to live on o Ecosystem services: things that ecosystems do "for free" that benefit us Examples: Can filter toxins from water, a place for fish to live, water to drink o Examples: Produce food Provide water filter pollutants from water Purify air Reduce flooding Remove carbon from atmosphere Decompose wastes Dampen effects of extreme weather Pollinate plants Provide medicines Create/ preserve soil Total economic value (Chart) Direct use value: resources directly used (water, fish, etc) Indirect use value: resources indirectly used (regulating services) Option value: our future possible use (leaving our options open) Bequest value: future generations possible use Existence value: right of existence (other living things have a right to exist) Threats to biodiversity Habitat loss: species lose the area in which they evolved and live o usually caused by human activity Agriculture Urban development Forestry Mining Pollution Climate change o greatest threat to biodiversity Ice in the artic is melting at a higher rate than ever before Species need to quickly adapt to the habitat loss or they go extinct Introduced species: species brought by human activity to an area in which they did not evolve o Can be intentional or unintentional o Often better competitor This is because of not being affected by the local biological controls o Not affected by local biological controls- pests and parasites o Often very difficult to eradicate once established o Only called invasive species if it becomes a problem o Example: zebra mussels in Great Lakes- disrupt freshwater ecosystems, damage man-mage structures Overharvesting: killing so many individuals of a population that it threatnes the populations survival o Organisms might be harvested for food, jewelry, medicine, decoration, superstition, misunderstanding Turtles were harvested for jewelry Elephants and rhinos killed just for their tusks Gorillas killed for their heads and hands Rattlesnakes killed so they would not be bitten due to their fear of snakes o K- selective species and those with restricted habitats especially vulnerable Do not breed very often and do not produce many offspring when they do o Species threatened by this: African elephants American bison Black rhinoceros o Species we drove to extinction this way: Passenger pigeon There used to be so many that they would block the sun when a flock flew by They were killed for their feathers or to eat Caspian tiger Felt threatened by them Global change: accelerated change in global climate, atmospheric chemistry, or ecosystems, resulting from human activity o Acid precipitation If a type of tree is very likely to be ruined by acid rain, then it could more easily go extinct due to the change in atmospheric chemistry o Water pollution o Climate change o Amount of species going extinct is much higher than before Conservation Small populations are especially vulnerable to factors that threaten biodiversity Small- population approach: study processes that cause extinction once population size is reduced Extinction vortex: once populations size is reduced, factors keep decreasing it until no survivors o genetic variation is important o Northern elephant seals: hunted to a small amount, but then the populations bounced back Avoided extinction vortex due to not suffering from inbreeding Minimum viable population size (MVP): minimal population size at which a species is able to sustain its numbers o Species- specific o Influenced by environment Effective population size: measures breeding potential, because some individuals in population don’t breed o Gives more accurate information about population's chances of survival Conservation goal: maintain effective population size above MVP Example: Indiana bat is a threatened species due to habitat loss or "white- nose syndrome" Declining- population approach: study of threatened and endangered populations that are declining, even if population size is above MVP o This approach focuses on environmental factors that cause decline in the first place o Examples: decline of red-cockaded woodpecker and conservation plan Lives in pine forests Picks the bark around their nest so the sap keeps snakes away Ecosystems actually need fires to keep a stable ecosystem Landscape and bio diversity Habitat fragmentation: breaking once- continuous habitat into smaller, unconnected pieces o This increases edge habitat Habitat edges: boundaries between ecosystems o More edge means less habitat for species who live in centers and more danger to them from predators and parasites o Example: wood thrush only nests in the centers of habitats, so more edges is bad for them Cowbirds like edge habitats and create problems for wood thrushes due to habitat fragmentation (more room for cowbirds and less for wood thrush) Because the "core" of a habitat is very close to the edge (due to habitat fragmentation) the cowbirds are invading the wood thrushes o Nest parasitism: laying their eggs in another bird's nests leaving the eggs to be taken care of by another bird Cowbird chicks can hatch and be much bigger than the other bird (example: warblers) and take over the nest Habitat corridors: habitat paths that connect fragments, provide benefits for breeding, dispersal o Example: habitats can be connected over a highway so animals can go between habitats without threat of being run over o Wild life overpasses Protected areas Biodiversity hotspots: relatively small area with numerous endemic (not found anywhere else on the planet)species and large number of threatened and endangered species o these are good choices for protected areas, but can be difficult to identify because the biodiversity of that area depends on which species you are talking about o The "hottest" hotspots are only 1.5% of earth's surface, but contain more than 1/3 of all species of plants, amphibians, reptiles, birds, and mammals Nature reserves: used to be set aside in an attempt to keep them unchanged forever, we now understand the importance of intermediate disturbance o Important questions: are numerous small reserves better than few large reserves? Not really. Fewer, very large reserves is actually better Example: for grizzly population to stay above MVP, Yellowstone national park would need to greatly increase in size o In some cases a little disturbance is good to stay a healthy ecosystem Zoned reserves: protected areas with a core of relatively undisturbed habitat, surrounded by areas that have been altered by human activity, and may be used for limited economic purposes (can only slightly be altered for economic benefit) o Also known as buffer zones o Often results in better protection because local people benefit o Costa Rica has high success with these reserves Sustainable Development Examples Agroforestry integrates crops with tree products and/ or livestock to make the most of limited space Ecotourism gives economic benefit to local people from conserving natural areas o Locals serve as nature guides, provide lodging and food, and sell handmade goods to tourists Renewable energy provides power without adding pollutants Green roofing decreases heating and cooling costs, and decreases "heat island" effect in urban areas Rain water harvesting provides water for showering, flushing toilets, washing dishes, and watering garden without depleting a well of ground- water supply How can you contribute? First reduce your consumption, then reuse everything you can, then recycle what no longer can be used o Carry a re-usable drink bottle, instead of repeatedly buying plastic bottles o Replace standard light bulbs with compact fluorescent lights (CFLs) o Use washable canvas tote bags for groceries, instead of plastic o Combine chores into one trip from home to reduce gas usage o Bike, walk, or carpool when possible Crash course video: https://www.youtube.com/watch?v=Kaeyr5-O2eU Lecture 12/1 Evolution via natural selection Misconceptions about evolution 1 Evolution is a theory about the origin of life a Correction: evolution deals with the way organisms have changed after they originated, the "branching" of the tree of life 2 Organisms are always getting better through evolution a Correction: evolution isn't "progress", environment determines whether a species is adapted well or poorly 2 Evolution means that life changed "by chance" a Correction: the organisms that are better- adapted to their environment survive; speed increases likelihood of survival for antelope (prey) and cheetahs (predator), which is not random 2 Natural selection involves organisms "trying" to adapt a Correction: genetic adaptation is not controlled by the organism; natural selection allows well-adapted individuals to survive 2 Natural selection gives organisms what they "need" a Correction: natural selection is not an intelligence that knows what organisms "need"; organisms that are better-suited to their environment will produce more offspring than those that aren't well- suited 2 Evolution is "just" a theory a Correction: in scientific terms, a theory is a hypothesis with a large body of supporting evidence, and nothing that has ever disproven it; not the same as "theory" used in common language (guess) 2 Gaps in the fossil record disprove evolution a Correction: fossils of many transitional forms exist (ex: whales and land mammal ancestors), but lack of fossils does not disprove the theory 2 Evolutionary theory is incomplete a Correction: science is constantly seeking new knowledge and modifying what we know based on discoveries; evolution is the only well-supported explanation for the diversity of life 2 Evolution supports "might makes right" a Correction: biological evolution cannot be applied to society; "social Darwinism" was an attempt at this, which allowed prejudices to be justifies (this has been proven false) 2 Teachers should teach "both sides" a Correction: there are tens of thousands of religious views concerning creation, none of which have any scientific basis and do not belong in a science class; issue usually stems from groups attempting to inject their religious dogma into scientific curricula 2 Evolution isn't a belief system, it’s a scientific theory a You can choose to accept or reject the evidence that supports the theory of evolution, but the theory is not something you do or don’t "believe in" Evolutionary theory states that.. There is descent with modification o Living species are descendants of ancestral species that were different from those of present day o There is change in genetic composition of populations from generation to generation Charles Darwin Traveled the world on HMS Beagle in 1831 (mission of voyage was to chart South American coastline) Collected animals and plants from South America, Australia, Malaysia, and Africa Noticed that island species were similar to mainland species Galapagos Islands important for their unusual species He noticed certain patterns during his traveling Adaptations Definition: inherited characteristics of organisms that enhance their survival and reproduction in specific environments New species arise from an ancestral form by gradual accumulation of adaptations to different environments Organisms share many characteristics (ex: DNA, metabolism, called "unity of life") Unity of life due to descent from common ancestor Descendant organisms accumulated adaptations, eventually developing into new species Natural selection Observation 1: members of a population vary in their inherited traits Observation 2: all species can produce more offspring than the environment can support, and many of these offspring fail to survive and reproduce Inference 1: individuals whose inherited traits give them a higher probability of surviving and reproducing in a given environment tend to leave more offspring than other individuals Inference 2: the unequal ability of individuals to survive and reproduce will lead to the accumulation of favorable traits in the population over generations Artificial Selection Same as natural selection, but directly caused by people Example: bacterial resistance by antibiotics Lecture 12/3 Artificial selection The same as natural selection, except it is due to humans picking certain characteristics to breed Natural selection Summary: o Process by which individuals with certain heritable traits survive and reproduce at higher rate because of those traits o Over time, can increase the match between organisms and environment o If environment changes, or individuals move to new environment, natural selection could result in adaptation to new conditions, sometimes giving rise to new species Important points: o Although natural selection acts on individuals, individuals do not evolve. The population is the smallest living unit that can evolve o Natural selection can only act upon heritable traits that differ among individuals in a population For snails with all the same shell shape but many different shell colors, natural selection could not change the shell shape, but shell color could be adapted to better fit the environment o Natural selection is always operating, but which traits are favored depends on the context in which a species lives The environment and species it interacts with will determine which traits are favorable The theory of evolution by natural selection o Overproduction: every species tends to produce more individuals than can survive to maturity o Variation: the individuals of a population have many characteristics that differ o Selection: some individuals survive longer and reproduce more than others do o Adaptation: the traits of those individuals that survive and reproduce will become more common in population Direct observation of Evolution Natural selection in response to introduced plant species o Soapberry bug (native) and balloon vine( native), and Goldenrain tree (introduced) in Florida o Balloon vine is native to Florida and its fruit is fed upon by native insect the soapberry bug o Balloon vine has become rare in FL and soapberry bugs there feed on introduced Goldenrain tree fruit instead o Soapberry bugs feed most effectively when the length of their beak matches the depth of the seeds within the fruit o Goldenrain tree fruit has 3 flat lobes, with seeds closer to its surface than in the round balloon vine fruit o Scientists predicted that natural selection would result in soapberry bugs with shorter beaks in populations feeding on Goldenrain tree fruit (which is what happened) Evolution of drug- resistant pathogens o 1/3 of people on the planet have Staphylococcus aureus on their skin or in nasal passages with no harmful effects o Some genetic varieties of this species (strains) are resistant to the antibiotic methicillin. These are called "methicillin- resistant" S. aureus (MRSA) o Increase in MRSA in the last decade o In 1943, antibiotic penicillin (derived from fungus) became first widely-used antibiotic, saving millions of lives o By 1945 over 20% of S. aureus strains were penicillin- resistant o Use of powerful antibiotic methicillin started in 1959 o MRSA strains appeared by 1961 o Methicillin works by deactivating a protein bacteria use to make their cell walls o Some S aureus populations were able to construct their cell walls using a different protein that wasn’t affected by methicillin o These S. aureus populations survived methicillin treatment, reproduced at higher rate than other populations and spread MRSA o Now some MRSA strains are resistant to multiple antibiotics, making treatment difficult Supporting evidence: Homology: similarity resulting from common ancestry o Depends on how far back you would call "recent" o Characteristics present in ancestor are altered by natural selection over time in descendants o Related species can have characteristics with underlying similarity but different function Human hands and seal flippers are similar in structure o Evolution can be though of as a remodeling process, not a creative one o Mammal forelimbs are homologous structures, with same arrangement of bones from shoulder to tips of digits, but with different functions o This anatomical resemblance would be highly unlikely if structures had arisen anew in each species o Additional homologies are visible when comparing early stages of development of different animal species All vertebrate embryos have a tail posterior to (behind) the anus All vertebrate embryos also have pharyngeal (throat) arches which develop into structures with very different functions Gills in fish Parts of ears and throat in mammals o Vestigial structures are homologies that are remnants of functional features in an ancestor that are not used by the descendant Pelvis and leg bones in some snakes Eye remnants buried under scales in blind cave fishes In humans: male nipples, body hair, appendix, tonsils, etc. We wouldn’t expect to see these vestigial structures if these animals had origins separate from other vertebrates Shows that evolutions is "not progress" Convergent evolution: distantly related organisms resemble each other because of independent evolutions of similar features in different lineages o Evolution explains how species that are only distantly related can appear so similar; they adapted to similar environments in similar ways o Example: sugar gliders and flying squirrels Both have flap of skin between forelegs and hind legs, small, furry Sugar gliders are marsupial mammals Young born as embryos and mature in an external pouch Most closely related to kangaroo, koala, Tasmanian devil Flying squirrels are eutherian mammals Young complete embryonic development in uterus Most closely related to human, cat, horse Both are adapted to gliding in forest habitat; their features are similar due to convergent evolution and are called "analogous" rather than "homologous" Homologous vs analogous o Homologous features share recent common ancestry, but not necessarily common function o Analogous features do NOT share recent common ancestry, but DO share common function Fossil record documents pattern of evolution o Shows that past organisms differed from present day organisms and that some have gone extinct o Shows evolutionary changes that have occurred in groups of organisms Example: horse species have gotten larger over evolutionary time, and lost digits on their feet o Shows origins of new groups of organisms Example: cetaceans evolved from ancestor of even- toed ungulates (deer, pigs, camels, cows) o Biogeography: study of geographic distributions of species Influenced by continental drift All landmasses were united into Pangea 250 million years ago Pangea broke apart starting 200 million years ago, separating organisms, preventing movement to some areas while allowing movement to others Lecture 12/8 More evolution Crash course video: o Taxonomy: evolution and genetics o Everything is related to each other at one point o Figuring out branches of evolutionary tree o Taxonomic system of classifying (phylogenetic tree of life): Species Genius Family Order Class Phylum Kingdom Protista, fungi, plantae, animalia (under eukarya domain) Autotrophs: plantae,(some protists) heterotrophs: animalia, fungi, (some protists) Domain Bacteria, archaea, eukarya o There's a lot of grey area in biology (system is not perfect but very good) o Linnaeus studied nomenclature and developed recent techniques based on homologous traits o Taxa: group of organisms o Binomial nomenclature: unique two part name for each species (genus and species) o Example: cat Eukarya (domain) Animalia (kingdom) Chordata (phylum) Mammalia (class) Carnivora (order) Felidae (family) Felis (genus) Catus (species) Phylogeny Phylogeny: evolutionary history of a species or group of species Binomial nomenclature: two-part Latin name unique to each species, containing first its genus name (capitalized) and second its species name (lowercase) and always set off from other text (usually italicized or underlined) o Homo sapiens o Can be abbreviated after first mention in text: H. sapiens Hierarchical classification: organisms grouped into hierarchy of increasingly inclusive categories o Each level is a "taxon" o King Phillip Came Over For Great Sex Kingdom, phylum, class, order, family, genus, species o Example: people Animals, chordates, mammals, primates, hominids, homo, homo sapiens Phylogenetic tree is a diagram showing hypothesis about evolutionary history o Branch point: common ancestor existed o Node: organism (at branch point) o Sister taxa: each other's closest relatives o Polytomy: spot that we arent quite sure how it evolved (multiple things coming from one point) Cladistics: using common ancestry to classify organisms o Species placed into clades (groups), including an ancestor and all its descendants o Clades are nested within larger clades Monophyletic: a taxon is only equivalent to a clade if it is monophyletic, containing an ancestor and all its descendants Paraphyletic: clade containing an ancestor and some, but not all of its descendants Polyphyletic: clade containing taxa with different ancestors As a result of descent with modification, organisms share some characteristics with their ancestors, and have some that differ from those of their characteristic Symplesiomorphy: a shared ancestral trait, such as the backbone in mammals Synapomorphy: a shared derived trait, such as hair in mammals Microevolution Microevolution: change in genes in a population over time o Mustangs have a variation in color due to microevolution What can cause this change in genes? o Natural selection o Gene flow o Genetic drift Lecture 12/10 Gene flow Gene flow: transfer of genes into or out of population due to movement of fertile individuals of their gametes Example: horses of different colors mate and their genes "flow" in the population Genetic drift Genetic drift; chance events that cause gene frequency to fluctuate unpredictably from one generation to the next, especially in small populations o Is an accident Founder effect: small number of individuals establish population with gene pool different from source population an example of genetic drift if founders are indiscriminately transported (like in a storm) Bottleneck effect: sudden change in environment drastically reduces size of population, by chance, certain genes are over or under represented in resulting population o Example: current cheetah population o Only a small population of cheetahs survived with was not representative of the entire gene pool of the population of cheetahs before o They are now very homogenous and have a lot of the same characteristics o Low genetic diversity More on natural selection This is the only mechanism that consistently causes adaptive evolution (unlike genetic flow and genetic drift) o Gene flow and genetic drift happen but do not lead to adaptive evolution Relative fitness: contribution an individual makes to gene pool of next generation, relative to contributions of other individuals o The fittest individuals make more babies that can make more babies, etc. "survival of the fittest" means that the best-adapted individuals pass relatively more of their genes to the next generation, because these individuals are more likely to survive and reproduce Modes of selection o Directional selection: conditions favor one phenotypic extreme or the other o Disruptive selection: conditions favor both phenotypic extremes o Stabilizing selection: conditions favor intermediate phenotype Sexual selection: a form of natural selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates Sexual dimorphism: males look different from females Speciation Species concepts answer the question: what is a species? o Biological species concept A species is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring- but do not produce viable, fertile offspring with other such groups Reproductive isolation: existence of biological barriers that impede members of two species from interbreeding and producing viable, fertile offspring Prezygotic (before zygote) reproductive barriers: block fertilization from occurring; works by doing one of these: Impeding mating attempts Preventing success of attempted mating Hindering fertilization if mating is successful Postzygotic (after zygote) reproductive barriers occur after fertilization; works by doing one of these: Ceasing developmental errors resulting in death Causing infertility Decreasing hybrid chance of survival or reproduction Limits: No way to evaluate the reproductive isolation of fossils Doesn’t apply to asexually- reproducing organisms Doesn’t explain how some species stay separate even though they sometimes interbreed (polar bears and grizzlies) o Morphological species concept Species identified by body shape and structure Applies to both asexual and sexual species Relies on subjective criteria o Ecological species concept Species identified by niche o Phylogenetic species concept Species identified as smallest group of organisms sharing a common ancestor, forming one branch of "tree of life" 20 other species concepts exist, each with benefits and drawbacks, Scientists use the BSC most often, but sometimes other concepts must be used when it doesn’t work 2 categories of speciation: o Allopatric speciation (other homeland) Involves physical separation 2 methods: Vicariance: ancestral (original) population is seperated somehow Dispersal: some individuals from ancestral population colonize a new area o Sympatric speciation (same homeland) Does not involve physical separation 2 methods: Disruptive selection: natural selection favors extreme phenotypes, at both ends of phenotypic spectrum Polyploidy: an organism has more than two complete sets of chromosomes
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