Chapter 4: Evolution And Speciation Flashcards Preview

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Flashcards in Chapter 4: Evolution And Speciation Deck (39):
1

Adaptions

Traits selected by natural selection

Adapted organisms survive

2

Phenotypic variation

In a population results from combined effects from genes and environment

3

Phenotypic plasticity

Variation among individuals in form, function, or physiology from the environment

4

Ecotypes

Locally adapted and genetically distinctive populations within a species

5

Heritability

Proportion of total phenotypic variation in a trait attributable to genetic variance

6

DNA replication is not _____

100% accurate, mistakes are known to occur

7

DNA mistakes are known as

Mutations

8

Micro evolution

Change in gene frequency within a population can occur both natural selection and random processes

9

Macroevolution

Leads to speciation

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Process of natural selection

Does not take the same form everywhere and at all times

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Stabilizing selection

Most populations have a high potential for evolutionary change

12

Stabilizing selection favours ....

The average phenotype

13

Directional selection

Favours an extreme phenotype over the average

14

Disruptive selection

Favours two or more extreme phenotypes over the average

15

Evolution through genetic drift

Occurs in alll sexually reproducing populations, but strength the changes occur in small populations

16

Genetic drift graph

AA = 0.25
Aa = 0.50
aa = 0.25

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Hardy-Weinberg principle

Based on Aa/Aa mating scenarios

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Generic drift

With a finite number of individuals producing a finite number of offspring, gene frequencies will change

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Platonic idealism

Single unchanging truth

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Biological species concept

Groups of actually interbreeding natural populations

21

Ecotypes

Genetically identifiable subclass of a species which evolved in response to a local environmental conditions

22

Phylogenetic species concept defines species

Based upon evolutionary history or phylogenetic similarity

23

Reproductive islolation

Broken into two isolating mechanisms

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Isolating mechanisms

Prezygotic

Postzygotic

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Prezygotic isolating mechanisms

Prevent two individuals from forming a zygote

26

Postzygotic isolating mechanisms

Occur after a zygote has been formed

27

Ecological isolation

Two individuals physically separated, such that they are unable to encounter each other

28

Temporal isolation

Individuals are fertile at different times

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Behavioural isolation

Both fertile and in same location but not proper behaviour cue

30

Mechanical isolation

Two individuals that have genetalia that don’t fit together

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Postzygotic isolating mechanisms

Equally effective at preventing production of a viable offspring

32

Hybrid inviability

Results if zygotic development is abnormal

33

Hybrid sterility

Occurs if the hybrid develops normally but is unable to produce viable gametes

34

Speciation is generally divided into three groups

Allopatric

Parapatric

Sympatric

35

Allopatric

Single group spatially subdivided

36

Parapatric

Population expands into new habitat within the pre-existing range of the patent species

37

Sympatric

Single parent population forms genetically distinct Su populations by natural selection without isolation

38

Alleles

Genes in an alternative form

39

Speciation

physical and ecological processes interact with selection and drift to produce new species