Ch. 13 How Populations Evolve Flashcards Preview

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Flashcards in Ch. 13 How Populations Evolve Deck (56):
1

Evolutionary Adaptation

An inherited characteristic that enhances an organism's ability to survive and reproduce in a particular environment

2

Evolution

Genetic change in a population or species over generations; all the changes that transform life on earth; the heritable changes that have produced Earth's diversity of organisms

3

What was Darwin's main idea?

Species change overtime and living species have arisen from earlier forms

4

Fossils

A preserved remnant or impression of an organism that lived in the past

5

What did Darwin write?

"On the Origin of Species by Means of Natural Selection"

6

How does petrification/fossil develop?

Minderals dissolved in ground water, seep into tissues of a dead organism and replaces the organic matter

7

Fossile Record

The chronicle of evolution over millions of years of geological time engraved in the order in which fossils appear in rock strata
- position in strata = age

8

Biogeography

The geological distribution of species
- historical contest of evolution

9

Comparative Anatomy

The comparison of body structures in different species
- anatomical similarities = common descent

10

Homologous structure

Structures that are similar in different species of common ancestry

11

What does "Evolution is a remodeling process" mean?

Ancestral structures originally function in one capacity are modified with new functions
- descent with modification

12

Comparative Embryology

The study of structures that appear during the development of different organisms
- closely related = similar stages in embryonic development

13

Molecular Biology

The study of molecular basis of gene and gene expression
- universality of genetic code

14

What are 4 evidence that validates the evolutionary view of life?

1) Biogeography
2) Comparative anatomy
3) Comparative embryology
4) Molecular biology
5) Fossils

15

How does population affect natural selection?

All species tend to produce excessive # of offspring, so natural resources are limited and there is a struggle to survive

16

Natural Selection

Differential success in reproduction by different phenotypes resulting from interactions with the environment; evolution occurs when natural selection produces change in relative frequencies of alleles in a population's gene pool
- gradual change in characteristics of population (Favored accumulates)
- screens variation

Nature determines which organisms live/die
- depends on adaptations
- survival of the fitness

17

Artificial selection

Selective breeding of domesticated plants/animals to promote the occurrence of desirable inherited traits in offspring
- modifying species
- over short time

Man determines who lives/dies
- selective breeding and could explain earth's diversity

18

What accounts for evolution of new species?

Heritable changes gradually accumulate

19

Theory of Evolution

Developed to explain the changes of organisms through time
- how organisms of past become organisms of today

20

Why was there a belief of "species are fixed and unchanging"?

Religion and short lifespan --> no observation or explanation

21

Who was Jean Baptiste Lamarck

First to oppose to species are not fond yet that changed.
- Law of Use and Disuse (muscles only)
- Law of inheritance of acquired characteristics

22

What are Charles Darwin's 5 assumptions?

1) There are more organisms born than can possibly survive
2) Limited amount of resources available
3) Variations exist among members of a species (differences)
4) Organisms with favorable variations to environment are well adapted and survive
5) These organisms mate and pass variation to offspring

23

Do humans obey natural selection?

No

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Populations

A group of individuals of the same species living in same geographic area
- smallest units that can evolve
- problem solutions: adapt, move, die
- change gradually over successive generations based on how adapted

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Population Genetics

Science of genetic changes in populations and of microevolutionary changes
- how populations of species evolve
- predicts how/when many of the traits will appear
- frequency of alleles changes with environment

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Gene Pool

Total collection of all genes in population at any one time

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Microevolution

Small changes in the gene pool over a number of generations

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Hardy-Weinberg Equilibrium

The shuffling of genes that occur during reproduction is not enough to change the genetic make up of populations
1) p+ q = 1
2) p^2 + 2pg + q^2
3) Gene frequency tend to remain constant b/w generations provided there is...
- mutation, gene flow, gene drift, natural selection, non-random mating
* Rarely met in nature

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Mutation

change or error in genetic code that produces new alleles (creates variation)
- beneficial = raw material of evolution

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Gene Flow

Migration, movement of individuals in/out of populations

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Genetic Drift

Chance, change in gene pool due to change
- only some with small populations (<100)
- bottle neck effect & founder effect

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Bottle neck effect

Population size is reduced drastically due to a natural environment

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Founder effect

A new area is colonized by a group creates genetic drift

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Modern Synthesis

A comprehensive theory of evolution that incorporates genetics and includes most of Darwin's ideas, focusing on populations as the fundamental units of evolution

35

Sexual species

A biological species; a group of populations with potential to interbreed and produce fertile offspring

36

5 Conditions of Hardy-Weinberg Equilibrium?

1) Population is very large
2) Population is isolated (no migrations of individual + allele)
3) Mutations do not alter the gene pool
4) Mating is random
5) All individuals are equal in reproductive success so natural selection doesn't occur
* rarely ever met

37

What are the 5 deviations from Hardy-Weinberg Equilibrium?

1) Genetic drift
2) Gene flow
3) Mutation
4) Non random mating
5) Natural selection

38

Morphs

2+ kinds of individuals/forms of phenotypic characteristic in a population

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Polymorphism

The existence of different forms; may pertain to a population in which 2+ morphs are present in readily available frequencies

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Cline

A gradation in an inherited trait along a geographical continuum; variation in a population's phenotypic features that parallels an environmental gradient (variable)

41

What two random processes generate variation?

1) Mutations
2) Sexual recombination

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Heterozygote advantage

Greater reproductive success in heterozygous individuals compared to homozygous

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Neutral variation

Genetic variation that provides no apparent selective advantage for some individuals over otehrs

44

What does "survival of the fitness" mean?

Survival of genes, not individuals or organisms

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Fitness

The contribution an individual makes to the gene pool of the next generation, relative to the contribution of other individuals in the population

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What does it mean to be the "fittest" organism?

You pass on the greatest # of genes

47

What are the 3 modes of natural selection?

1) Stabilizing selection
2) Directional selection
3) Diversifying selection

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Stabilizing selection

Natural selection that favors intermediate variants by acting against extreme phenotypes
- stable environment that reduces phenotypic variation

49

Directional selection

Natural selection that acts against the relatively rare individuals at one end of a phenotypic range
- common with environmental changes

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Diversifying selection

Natural selection that favors extreme over intermediate phenotypes

51

How does human activity affect variations in populations? Examples?

Decreasing genetic variation (less opportunity)
- pollution, burning fossil fuel, pesticides, habitat destruction, overheating, introduction of non-native organisms

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Examples of natural causes that variation in populations...

Drought, disease, floods, volcanoes, hurricanes

53

Loss of biodiversity is...

Human activity plus natural causes

54

What are the conditions of loss of biodiversity?

1) Threatened species
2) Endangered species
3) Extinct

55

Why are small populations problematic?

There is too few variation.
- no genetic makeup to adapt
- inbreeding

56

What are solutions to loss of biodiversity?

1) Captive Breeding Program
2) Wildlife Preserves
3) Germ Plasm Bank
4) Changing Human Behavior