Evolution Flashcards by Hannah Provenzano

What are the evidences of evolution?

Homologous structures

Analogous structures

Comparative embryology

Vestigial structures

Molecular biology

Homologous genes

Biogeography

Fossil records

Artificial selection

Direct observation

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What are homologous structures?

homo = the same
logous = having a correspondence / relation

shared physical structure, therefore common ancestor

same structure (bones in same relative position), different function / appearance = ADAPTIVE RADIATION

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What are analogous structures?

ana = again, anew, TOWARDS
logous = having a correspondence / relation

similar function, different structure, therefore convergent evolution

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What is comparative embryology?

some homologous structures only seen in embryos

therefore, development programmes of vertebrates have small variation of common ancestor

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What are vestigial structures?

homologous structures to other organisms, yet NO PURPOSE

therefore, reduce = evolutionary “leftovers” = vestigial structures

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What is molecular biology?

principle of common descent
REINFORCED by modern biochemistry + molecular chemistry

code to translate nucleotide sequences into amino acid sequences
ESSENTIALLY SAME 4 FOR ALL ORGANISMS (A,C,G,T)

DNA similarity (diversification) = relatedness of organisms

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What are homologous genes?

idea behind 2 species have ‘same gene’ bc of common ancestor

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What is biogeography?

geological distribution of organisms follows pattern of distribution of evolution and tectonic plate movement

evidence: fossils
e. g.: marsupials common in Australia & placentals rare

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What are fossil records?

preserved remains of previously living organisms

most organisms never fossilize

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What does fossilisation occur?

soft body parts decay, hard parts (calcium carbonate) remain

absence of condition = formation of deposits

= fossils

+ preserved trails = covered by sediments (becomes sedimentary rock), forms in stratas

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How are fossils dated?

radiometric dating = process that measures radioactive decay of certain elements

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What is artificial selection?

intentional reproduction of individuals in a pop. with desirable traits

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What is direct observation?

visible evidence of evolution

e.g. colour change, chemical resistance

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What is speciation

pop. of a species gradually diverge into seperate species by evolution

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What is Darwin’s theory?

natural selection:

mutations = variation

unfavourable mutations selected against

reproduction and mutation

favourable mutations increase survival

reproduce

MOST RESPONSIVE SURVIVES

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What is Lamark’s theory?

species changed as a result of the habitual use/disuse of a feature

modifications passed in genes over time

What are the factors of the natural selection theory?

traits are heritable
overproduction of offspring - competition for resources
struggle for survival - environmental pressures = diff. reproduction
variation in pop.
reproduce
evolution

What is the mneumonic for the theory of evolution?

ICE AGE

Inherited variation
Competition
Environmental pressures

Adaptation
Genotype frequency
Evolution

What are the different types of evolution?

divergent

convergent

parallel

coevolution

punctuated equilibrium

gradualism

Can you explain divergent evolution for me?

2 species gradually become diff.

responsible for diversity of 1st cell

responsible for evolution

specification

homologous structures

e.g. Finches

Can you explain convergent evolution for me?

not closely related

independently evolve similar traits

result of environmental pressures

analogous structures

e.g. insects / bats / birds
MIMICRY - consequence of warning coloration

Can you explain coevolution to me?

equal to / more than 2 species evolve in tangent by exerting selection pressures on each other

usually close environmental interactions
e.g. parasite, prey & predator, competition, mutalism

Can you explain to me punctuated equilibrium?

evolutionary change in short periods of time (~ 500,000 years) and tied to speciation

contrasts Darwin’s theory, evolution only happens in rapid bursts

Can you explain to me gradualism?

gradual selection & variation

small variations eventually change population

What are the types of selection and draw their graphs?

directional disruptive stabilising sexual selection artificial selection

What does directional selection involve?

extreme phenotypes favoured, therefore shift to that phenotype advantageous allele increases, consequence of diff. survival & reproduction compared to other phenotypes

What does disruptive selection involve?

extreme values favoured over intermediate ones trait variance increases = division into 2 species

What does stabilising selection involve?

favours intermediate traits / variants pop. mean stabilises on non-extreme trait most common type of selection

What does sexual selection involve?

members of 1 biological sex choose mates of the opposite sex compete wt members of same sex for access to opposite sex

What does artifical selection involve?

humans use plant / animal breeding to selectively develop particular phenotypic traits by selecting which would sexually reproduce

What are the mechanisms of evolution?

PRINCIPLE: evolution can only occur if there is change in gene frequency wtin a pop. over time mutations natural selection gene flow genetic drift

Can you explain what the mechanism of evolution known as mutations means?

random change in pop.'s gene pool change in DNA of 1 / more chromosomes mutations = new alleles = VARIATION

Can you explain what the mechanism of evolution known as natural selection means?

occurs when organisms subjected to environmental pressures genes of less fit organisms eventually lost MOST IMPORTANT MECHANISM

Can you explain what the mechanism of evolution known as gene flow means?

evolution during migration from 1 group to another migrating individuals interbreed = VARIATION therefore establishes gene flow increases similarity btw remaining pop.s of the same species

Can you explain what the mechanism of evolution known as genetic drift means?

small group of individuals leave pop. & establish a new pop. in a geographically isolated region fitness of species does not = genetic drift DOES NOT OCCUR IN LARGE POP.