Flashcards
Evolutionary Biology_1
Cards in this deck (32)
- 1Darwin's Theory of Evolution1.) Evolution happens (populations change over time)
2.) Evolution happens gradually
3.) Speciation occurs
4.) All species share a common ancestry
5.) Much evolutionary change is caused by Natural Selection - 2Evidence/Predictions of Theory of Evolution~ Increasing complexity: gradual change in fossil record complexity
~ Speciation: lineages split
~ Transitional forms: fossil evidence of progression between ancestor and modern form
~ Retrodictions: "bad design", 'dead' genes, "Nothing in biology makes sense except in the light of evolution"
~ Natural selection: observe it happen in nature (Darwin's finches) - 3When is a scientific theory considered "TRUE"?When it has been repeatedly tested and confirmed through observation and experimentation
- 4Darwin's Four Postulates of Natural Selection1.) Variation: individuals differ within a population
2.) Inheritance: differences are heritable; passed from parent to offspring
3.) Selection: some individuals are more successful at surviving and reproducing
4.) Not mere luck: successful individuals succeed because of various heritable traits - 5Ernst Mayr (1991) Natural SelectionFact 1: Super fecundity- large numbers of offspring
Inference 1: Competition
Fact 2: Steady populations- some survive, some don't
Fact 3: Limited resources
Inference 2: Differential survival
Fact 4: Individuals are unique
Fact 5: Heritability of differences
Inference 3: Evolution over time - 6Evolution in 19th Century (Problems)~ Variation: Unaware of mutation/DNA - thought it was finite (could run out)
~ Poor fossil record: Little faith in completeness - poorly preserved, thought we'd never find better fossils/ancestors
~ Inheritance: Blending - dilution of traits, no idea of inheritance/Mendelian ideas
~ Time: 15-10 million years - earth was too young for evolution to have occured - 7"Modern Synthesis" for evolutionary ideas~ Mendelian inheritance 1900: discrete units
~ Population genetics 1920's/30's: discrete units get passed on/inherited- Fisher, Haldone & Wright
~ Linking population genetics with Darwinism 1930's/40's -Dobzhansky & Mayr
~ Double helix DNA 1953: explain Mendelian genetics - 8Adaptive Radiation (definition)The divergence of a clade into populations adapted to many different ecological niches
- 9Adaptive Radiation (examples)Darwin's finches (beak diversity)
African cichlids (jaw shape diversity) - 10Natural Selection Necessary Conditions1.) Variation: individuals within species are not same
2.) Inheritance: traits are heritable; passed from parent to offspring
3.) Overproduction of offspring: more produced than survive
4.) Not random: reproduction and survival are not random (some traits increase fitness or are advantageous) - 11Natural Selection (definition)Natural selection is the main mechanism that produces adaptive evolution (response). It changes trait distribution within a generation.
- 12Nature of Natural Selection~ Acts on individuals
~Consequences occur in population
~ Acts on phenotypes
~ Changes allele frequencies
~ Can produce new traits
~ Acts on existing traits - 13Natural Selection is NOT. . .Adaptation doesn't involve trying
Natural selection doesn't grant organisms their 'needs', 'solve problems' or 'provide tools'
Perfecting
Random - 14Adaptation (definition)A character modified as a result of a selective advantage through improved function
- 15Adaptions. . .- are a variation of an earlier form
- are heritable
- enhance fitness (survival & reproduction)
-produced or maintained by Natural selection
-recognized by their: complexity, precision, efficiency, 'appearance of design', broad taxonomic distribution - 16Identifying adaptations (problems)- Traits have arisen only once in a common ancestor: no longer sure of purpose
- Traits of character may be different than what was selected for
- May be cultural/learnt
-May simply be correlates of other traits - 17Limits on Adaptive EvolutionTrade-offs
Constraints - 18Evolutionary constraintsRestrictions or limitations on the course or outcome of evolution. Due to evolutionary origins (past origins influence present actions)
- 19Trade-offsA trait is good for one situation but not another.
- 20Sexual Selection (definition)A difference among members of the same sex, between the average mating success of individuals with a particular phenotype versus individuals with another phenotype
- 21HomologySimilarity in a trait due to common ancestry
- 22HomoplasySimilar traits that appear independently in multiple taxa without phylogenetic continuity
- 23AnalogySimilarity of function across organisms regardless of phylogenetic relationships or inheritance of the trait
- 24Problems with sex- Finding a mate takes time & energy
- Mate may demand additional resources
- Sexually transmitted diseases
- Mating may prove to be infertile
- Produces fewer offspring - 25John Maynard Smith (1978) Evolution of SexNull hypotheses:
- Female's reproductive mode does not affect number of offspring
- Female's reproductive mode does not affect probability of offspring survival - 26Problems with John Maynard SmithAssumption 1: Female's mode of reproduction does not affect number of offspring. Untrue when male parental care.
Assumption 2: Female mode of reproduction does not affect survival of offspring. Does sex offer a selective advantage-i.e exposure to mutagens/parasites - 27Paradox of sexSex serves the species at the expense of the individual.
- 28Adaptive Value of Sex (theories)Muller's Ratchet -genetic drift with mutation makes sex beneficial (gets rid of bad or deleterious mutations)
Red Queen -selection in a changing environment makes sex beneficial (selection for good genes/need to continually improve) - 29Geographic PatternsEndemic: range of species restricted to a particular area (only in one place)
Disjunct distributions: related groups of species occur in widely separated localities - 30Factors influencing Biogeographic DistributionsEcology: competition for resources, habitat distribution, fundamental vs realised niche.
Geography & Climate: dispersal (corridors, filter bridges, sweepstakes), climate (glacial maxima/minima), vicariance (mountains, continental drift, rivers etc) - 31Vicarianceexisting disjunct distribution formerly a continuous distribution that somehow became fragmented by:
-extinction of intervening populations (habitat change)
-separation of land mass into two (continental drift) - 32Ecological Species ConceptSpecies are a set of organisms exploiting a single niche (adaptive zone)
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- 200 level Evolutionary Biology (ZOOL 222) Flashcards on Evolutionary Biology_1, created by Nia O'Connor on 08/10/2015.
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- Nia O'Connor · Oct 2015
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- Feb 19, 2016
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- Created by Nia O'Connor · Oct 8, 2015
- Copied by Nia O'Connor · Oct 8, 2015
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