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Exam 1
Evolution and Speciation Chapters 20-23
| Question | Answer |
|---|---|
| Postzygotic Isolation Mechanisms | prevent normal development of organisms to reproduce adults |
| Random changes may cause speciation by... | reproductive isolation |
| Adaptive radiation can result in... | character displacement |
| What is key to the biological species concept? | reproductive isolation |
| species that occur in the same area are called... | sympatric |
| The wings of birds and bees are an example of | Homoplastic traits |
| Paraphyletic Group | inclues the most recent common ancestor but not all of its descendents |
| the principle of parsimony is used when... | there are conflicts among characters |
| Members of a clade always share... | synapomorphies |
| The Principle of Parsimony | the simplest pattern of the phylogeny is the one that most likely happened. |
| Data needed to form a cladogram | 1. Select an outgroup 2. Build a set of characters(traits) 3. Assign character states to each taxon. 4. Analyze characters for homology |
| Reproductive Isolation methods | 1. Prezygotic isolation 2. Postzygotic isolation |
| biological species concept | A species is a group of organisms that can interbreed and produce viable and fertile offspring. Can mate with members of their own species but not with others. |
| Problems with the biological species concept... | organisms from different species that are isolated from each other can still reproduce. Organisms that reproduce asexually. Can breed in artificial conditions. Ex. Ligers at zoo |
| Prezygotic isolation | Geographic isolation Ecological isolation Behavioral isolation Temporal isolation Mechanical isolation |
| How would populations separate? | A barrier forms The founder effect |
| Allopatric Speciation | Geographic isolation stops gene flow. Environments may contain different selection pressures Random mutations End result: populations evolve reproducing isolating mechanisms |
| Sympatric Speciation | Speciation among individuals in same geographic locality Can occur by: Allopolyploidy or disruptive selection Cichlids of Lake Barombi Mbo in Africa |
| Character Displacement | Evolution of niche divergence in separate competing species Reduces competition |
| A monophyletic group | includes the most recent common ancestor of the group and all its descendants |
| Homoplasy | convergence or reversal reversals can remove synapomorphies |
| How to tell the difference between homoplasy and homology? | use cladistics: synapomorphies indicate relationships Apply mathematics: Principle of parsimony, Maximum liklihood |
| Systematics | science of forming hypothesized evolutionary relationships of organisms |
| Clades | all the descendents of a common ancestor |
| derived traits | traits that define a taxonomic group traits that have evolved since its most recent common ancestor Ex. Crocs- 2 degree palate in mouth |
| Ancestral Traits | Evolved in their evolutionary past. Ex. Crocs- hole in skull in front of eye socket |
| synapomorphies | create clades derived traits shared by 2 or more taxa all synapomorphies are homologous traits but not all homologous traits are synapomorphies |
| Analogous traits | same function, different structure. Ex. can all fly but they didn't inherit it from common ancestors |
| Ancestral traits | pleisiomorphic triaits and apomorphic(derived) traits |
| Sister taxa | taxa derived from an ancestral node Ex. Crocs and birds Every other descendant from that common ancestor |
| Nodes | branching points splitting of phylogeny represents a common ancestor |
| outgroup | what you compare the ingroup traits to. Something that is not a member of the ingroup but who is more distantly related |
| ingroup | what we are interested in learning the relationships of |
| taxa | all of the species |
| phylogeny | shows a pattern of descent Looks at similarities in a gene sequence in species |
| character displacement | the trait(character) has been displayed something in your phenotype will change niche overlap will lead to competition 2 species |
| adaptive radiation | they radiate out as they adapt to new niches. rapid evolution from a common ancestor Ex. drosophilia on the Hawaiian islands |
| Ring species | can mate with the ones next to each other but cannot mate where they meet back up |
| Allopolyploid Speciation | different species mate with other species |
| Sympatric speciation | speciation among individuals in the same geographic locality |
| Allopatric speciation | founder effect geographic isolation stops gene flow environments may contain different selection pressures random mating (genetic drift) evolve producing isolating mechanisms geographically separated from the rest of the species ex a barrier (river) |
| Founder effect | some individuals can get isolated by maybe a storm onto an island and they can become an allopatry |
| Hybrid infertility | if they mate out of their boundary, their offspring cannot reproduce Ex. a horse and a donkey make an infertile mule |
| Ecological isolation | live in same area but different habitats in that area. Ex. wet and dry |
| Geographic isolation | causes them to not be able to reproduce because the're in two different places |
| Temporal isolation | when species mate or breed at different times of the year. |
| Mechanical isolation | male and female parts don't match up |
| prezygotic isolation | geographic isolation causes them to not be able to reproduce Ecological isolation Behavioral isolation temporal isolation mechanical isolation |
| what did Darwin study? | Morphology of finches on the Galapagos Islands |
| What did Darwin propose in his books? | species are not fixed evolution is gradual descent with modification natural selection |
| what is descent with Modification? | common ancestors give off new species |
| requirements of natural selection | phenotypic varience variation is heritable phenotype influences survival and reproduction(fitness) |
| Natural selection | the environment determines what happens |
| evolution | change in genetic makeup of a population over time |
| population genetics | monitor genotype and allele frequencies of a population over time assumes 1 gene with 2 alleles combines evolutionary mechanisms with medelian genetics |
| Microevolution | change within species to adapt to the environment |
| Macroevolution | new species occur from common ancestors |
| Hardy-Weinburg Principle | no random mating no mutations no gene flow no selection (artificial/natural) occurring Large population size |
| Gene flow | random change in allele or genotype frequency |
| if a population is in genetic equilibrium then... | allele frequency is constant genotype frequency is constant |
| Large population | population bottleneck founder effect |
| agents of evolutionary change | mutation gene flow non-random mating must not occur random genetic drift natural selection |
| population bottleneck | an event drastically reduces the population. Many alleles are lost from the original pop. now the pop. as a whole have few genetic charac. and face a higher level of genetic drift. disease could wipe them all out since they all have almost the same genes |
| Natural selection | variation is heritable how likely you are to produce natural selection acts on the individual but it is the population that evolves |
| Ellis-Van Crevald | Amish Disease |
| Positive Frequency-dependent selection | the rare one is prey bc it sticks out the more common you are the higher your fitness ex. organisms that blend in with their environment are less likely to be prey |
| oscillating selection | The Grants studied finches and their beak sizes oscillated in size depending upon the environment. Weather influeces what plants survive resulting in different types of seeds the birds have to eat. Need a bigger beak for bigger seeds |
| Heterozygote Advantage (overdominance) | Heterzygoes have a greater fitness that homozygotes Deleterious allele stays in population Ex. malaria in Africa, people with the heterzygous trait of sickle cell makes them immune to malaria. |
| evidence of natural selection | peppered moths and industrial melanism increases moth fitness birds see in UV light so it's easier for them to spot the white one(which blends in to us) than the dark one. Now dark ones are becoming rare |
| Homologous Limb structures | same structure different use similar bones just modified in different ways anatomy suggests common ancestory |
| atavism | reappearance of ancestral trait, with the genes that DON'T get turned off Ex. yolk sac in ancestors instead of a placenta. platypus lay eggs. we have the structure to make yolk, then it goes away. |
| Vestigial structures | you no longer have any use for a trait so those genes are turned off human embryos have a tail but then it's turned off and goes away |
| bobos | type of chimp sex crazy prostitution trade sex for food post-conflict reconciliation |
| Human-chimp similarity | share about 98% of DNA with chimps share personalities-the use of tools |
| Chromosome fusion in ancestor | we have 46. they have 48 P&Q have fused together Have a telomere on each end and in the middle of one of the centromeres are inactive |
| convergent evolution | distantly related organisms evolve similar phenotype sugar gliders and flying squirrels |
| Answering Darwin's critics | 1. Evolution is "just a theory" 2. Fossil record 3. Evolution and 2nd law of Thermodynamics(it violates it) |
| 2nd Law of Thermodynamics | violates 2nd law bc it's disorder to order. Entropy of a closed system never decreases, it increases or stays the same. Earth is not a closed system- the sun is our energy source |
| Negative frequencey-dependent selection | How frequent or common you are, affects your abundance. If you're common you're prey, if you're not common you're not prey. The more common you are the lower your fitness |
| Disruptive selection | select for the tails the extremes overlap in one population |
| Who wrote the Principles of Geology? | Charles Lyell |
| Increase(or decrease) may not occur if... | there is no genetic variation in the pop for the trait genes determining the trait have pleiotropic effects genes determining the traid interact with other genes. the rate of gene flow among pops is high |
| Mutation | a change in the nucleotide of a gene produces variation for natural selection to act on |
| Evolutionary fitness | number of reproductive offspring reproduced over an individual's lifetime low fitness-few offsring(5 eggs from chick) high fitness-high offsrping(20 eggs from chick) |
| Directional selection | bell curve population shifts from side to side |
| stabilizing selection | select for the middle of the bell curve |
| Who wrote the Essay on the Principle of Population? | Thomas Malthus |
| Gene flow | immigrate/emigrate as they move they might bring in new genes |
| Biological species concept | group of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups |
| Morphological species concept | if they look different then we make them different. can be deceptive sometimes bc different species can look a lot alike or different organisms of the same species look different |
| intelligent design | "theory" that certain features of the universe of living things are best explained by an intelligent cause not an undirected process such as natural selection. Paley's "Argument from design": finds a watch on the beach it had a designer. didnt form itself |
| Irreducible complexity | the theory that an organism must have all of its parts to be able to function. eubacteria flagellum is not irreducibly complex bc it's missing proteins and it still functions |
| for a trait to evolve by natural selection there must be... | variation among individuals a mechanism of inheritance fitness differences among individuals based on that trait |
| genetic drift | occurs in all pops. has the greatest effect in small pops can reduce genetic variation in a pop can lead to loss of alleles in isolated pops |
| disruptive selection favors... | phenotypes at both ends of the range |
Created by:
montes_jl
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