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54 Cards in this Set
- Front
- Back
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Pre –zygotic isolating mechanism occurs before conception
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Remember this note...
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Geographic (spatial) isolation
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mean that they are so separate that they never encounter each other. Ex. 2 species of squirrels in the grand canyon that were separated by the river and the outcome was that these two accumulated differences and they could not speciate w/one another
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Ecological isolation
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here we have sympatric population that sub-divide the pop that they never encounter each other, this hinges on subdivision of a habitat Ex. Fruit maggots we had one group specializing on Hawthorne fruit vs. apples , therefore they never form a zygote Ex. warblers in a tree – this lineage has been subdivided into 5 different groups, they all feed in different level of branches, mate in different areas, they never encounter one another, therefore they keep these separate lineage from
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temporal isolation
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not breeding at the same time Ex. fish species do broadcast spawning, this means that they let go of all of there eggs and the male let go of all of there sperm So, you might have one species that lets go of there stuff at dusk and another that lets theirs go at dawn Ex. 13 yr & 17 yr cicadas, they stay under ground for 13 years & the other till 17 years then each separate group come out and mate with one another, but the 2 groups never mix
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Behavioral isolation
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the emerging species stay separate b/c of different mating rituals and if one doesn’t do the mating dance right, then they do not mate
Ex. blue-footed boobies – these birds dance, show off their blue feet, if they are not blue of doing the dance right then they do not breed Ex. fireflies – they do different signal to attract a possible mate who has the same blinking signals Ex. crab Ex. moths – they use different pheromones to attract other moths to mate |
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Mechanical Isolation
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reproductive parts fit only one type of possible mate, if it doesn’t fit then they do not reproduce
Ex. damselfly penises – there are 4 different penis shapes Ex. spider copulation w/pedipalps if his doesn’t fit hers then it is not going to work |
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Gamete isolation
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if somehow the gametes do meet up (an egg and a sperm) they will not form a zygote
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Post-zygotic isolation mechanisms
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we have formed a zygote w/an egg and a sperm, but what ends up happening is that the zygote doesn’t end up living
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In the Post-zygotic isolation mechanisms the zygote end up doing what 3 possibilities?
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1) Hybrid in-viability
2) Hybrid stability 3) Hybrid breakdown |
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Hybrid in-viability
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mean that the offspring will not make it past the zygote stage, possibly the chromosome #/s do not match up
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Hybrid stability
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a full grown zygote lives to reproductive age but can not reproduce
Ex. donkey x horse => mule BUT MULES can not mate with one another |
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Hybrid breakdown
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species I mated w/ species II, and the hybrid offspring is then fertile F1 So, F1 x F1 => F2 this generation has low fitness
Ex. copepods in LA – are crustations that live in tide pool in LA, they mated this species in lab and the F2 gen had low fitness, which they turned out to be unproductive in reproduction |
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Classification & Phylogenic’s
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Ex. Dog is closely related to a foxes and wolves b/c they are all carnivorous, etc
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Linnaean classification system
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was developed by Carolus Linnaeus – if is a higher archeal scheme in which you can look at different groups by classifications
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Current 5 Kingdoms:
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1) Animalia
2) Plantae 3) Protista 4) Fungi 5) Monera |
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Name the list of invested hierarchy
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Kingdom -
Phylum (pl. phyla) - Class – looking w/in one class we next have Order – these orders are set up differently than another Family – Genus – Species – |
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Genus and species is based on?
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a BINOMIAL NOMENCLATURE
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Genus (always uppercase) species (always lowercase)
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Canis lipis
C. (abrev. for Californicus) familiaris ** You must pair a species name with a Genus |
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Taxon
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is a biological word for a group (pl. taxa)
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Taxonomy
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is the science of classifications
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Linnaeus felt that you can classify anything what is the best way to describe organisms?
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Morphological descriptions best describes organism
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Cladistics
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it works at any taxonomic level, this means that you will be using a picture diagram to look at the relationship between any organisms
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PHYLOGENY
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diagram of hypothesized evolutionary relationship among taxa, this diagram shows which is living and which is extinct
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Extant
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taxa (organisms) that are living
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Extinct
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organisms that are not living
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Node
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Any time there is a split
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SISTER GROUPS
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Split at a node into two groups and placing these two groups like examples A,B and D,E
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Phylogeny is approximately equivalent to a cladogram
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Phy- includes ancestors
Clado- shows extant taxa only |
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When making a phylogeny, what are some false assumptions?
Also, give a phylogeny example: |
Assumption: once a character evolves, all descendent taxa inherit that trait
One thing you have to be careful with is that you need to beware of reversals of state Q might have one characteristic that when F in turn has a trait different than Q but is most similar to that of S Example from the HO Phylogeny of the Wingiphorae, 9-11-06 Long legs is a perfect example of a shared derived character, M,N received it from P and P from R |
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radial symmetry
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Phylogeny branch w/jelly fish and one that is w/sponges
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bilateral symmetry
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when a Flatworm & anything that evolves after the sponges & jellies follow
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What is Shared derived characters and name the 2 forms of distibution?
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it is phenotypic similarities among taxa that were inherited from a common (shared) ancestor (synapomorphies), which either has a Limited distribution or Broad Distribution
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Limited distribution of a trait
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suggests that it is a derived character
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Broad distribution of a trait
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suggest that it has been around for a long long time, and you assume that it is an ancestral trait, likely an ancestral state
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** How must you be careful when you label your phylogeny traits?
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you must choose your characters carefully
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What are the three ways you can arrange your taxa?
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1) MONOPHYLETIC group
2) PARAPHYLETIC group 3) POLYPHYLETIC group |
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MONOPHYLETIC group
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which means that it contains an ancestor & all its descendent taxa
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PARAPHYLETIC group
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which contains some of the ancestors, but not all of its descendent taxa
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POLYPHYLETIC group
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which means that the gropup contains the descendents of two different ancestors; leaves out the Common ancestor that would unite the two or multiple groups
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What are the 2 Major Goals of Phylogenetics?
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1) Make monophyletic groups
2) Follow the principle of parsimony |
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How do you make monophyletic groups?
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Fill in the answer later. . .
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What are the principle of parsimony?
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the simplest explanation for all the available evidence, this means that you will make a phylogeny by choosing the explanation that requires the fewest independent origins & reversals of state that limit the number of changes to a minimal, (this is done mainly b/c it would show that it is the most likely explanation)
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What are the 4 TOOLS used for constructing phylogenies?
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1) HOMOLOGOUS characters
2) Conservative characters 3) FOSSILS 4) Genetic Data |
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HOMOLOGOUS characters
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similarily in characters due to shared ancestor
EX. vertebrate forelimbs, human, frog, bat, whale horse they all inherited a basic bone structure from a common ancestor, but natural selection has furthermore taken this design and let it best fit the individual that used it |
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Conservative characters
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not strongly affected by recent evolutionary events. ( characters are conserved “thru time) EX. cleavage patterns, have two specific forms EX. coelom formation has (2) specific forms EX. Hox genes in animals, determines how an animal develop, this is a trait that has conserved thru time EX. an earthworm and a crab, human, sea stars; earthworms and crabs have the same cleavage pattern, just like human’s and sea stars do…
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FOSSILS
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EX. transitional fossils are especially helpful to us b/c they show intermediate body forms/stages, (steps along the way of growth that ultimately lead up to a big change) EX. Archaeopteryx has a bunch of reptilian traits and also bird like traits
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What is Genetic Data, and give an example:
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today phylogenies is greatly dependent upon data kept or compared about
- Sequences of DNA - sequences of amino acids EX. cytochrome-C (conservator character) They compared humans cytochrome-C w/that of a chimps and they were ALL identical Human – rabbit have 8 differences Human - tuna have 20 differences Human - rice have 37 differences |
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Name 2 ways Ways to go wrong when constructing a phylogeny?
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1) Reversals of state
2) Convergent evolution |
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reversals of state
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is that when the ancestral character had long legs but the present individual had short legs, then it is believed that an earlier ancestor had Long legs
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Convergent evolution
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similar structures that evolve due to sharing similar selection pressures, not due to common ancestry.
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Give an axample of Convergent Evolution:
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EX. insect wings & bat wings
EX. Feeding structures in baleen whales & flamingos |
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Analogous characters
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this means that there is a similarity between different species due to adaptation to a similar way of life rather than inheritance from a common ancestor(maybe superficial appearance), but not evolutionary origin; often the result of convergent evolution
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Homologous characters
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any trait showing marked similarity between different species, due to inheritance from a common ancestor
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Give a Linnean example of classes:
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1) Class Reptilian
2) Class Aves is an example of paraphyletic group |
