Chapter 12- Forces Of Evolutionary Change Flashcards Preview

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Flashcards in Chapter 12- Forces Of Evolutionary Change Deck (18)
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1
Q

Evolution

A

“Descent with modification”

Organisms come from a common ancestor and adapt to their environment

Occurs when allele frequencies change from one generation to the next

2
Q

Levels of organization

A

Organism—>Population—>Community—>Ecosystem

3
Q

Population

A

A group of interbreeding organisms of the same species

4
Q

Gene pool

A

Entire collection of genes and alleles

Differ from population to population

5
Q

Lamark

A

Believed organisms become adapted to their environment during their lifetime and pass these adaptations to their offspring

6
Q

Charles Darwin

A

Evolution through natural selection

His work with finches in the Galápagos Islands distinguishes 14 different types with varying beak lengths but all other traits similar

7
Q

Artificial Selection

A

Humans choose desired features, allows only those that best express qualities to reproduce

8
Q

Natural Selection

A

Environment determines which individuals will survive and reproduce

Fittest individual possesses the best adaptations that increase chance of survival

9
Q

3 step process in which the environment chooses the fittest individual

A
  1. Members of a population have qualities that can be passed down genetically
  2. Organisms produce too many offspring for the amount of resources available in the environment
  3. Competition for resources ensues and Organisms that are better adapted to the environment survive and reproduce, usually passing down the advantageous traits
  4. Over time a larger proportion of the population have those advantageous traits
10
Q

Genotype determines phenotype

A

Organisms do not adapt based on need

Variation within a population will lead to new genotypes which lead to new, better adapted traits (phenotypes)

11
Q

3 Ways natural selection can shape a population

A

Directional

Disruptive

Stabilizing

12
Q

Directional

A

One phenotype is favored over another

13
Q

Disruptive

A

Extreme phenotypes are favored over an intermediate

14
Q

Stabilizing

A

Intermediate are favored over extremes

15
Q

Genetic Drift

A

Random chance changes in allele frequencies

More pronounced effect in smaller pops

Can lead to complete loss or fixation of certain alleles in a pop

16
Q

Founder Effect

A

Small group of individuals leave main pop and start a new colony

Gene frequencies change based on those possessed by the “founders”

17
Q

Population Bottleneck

A

Pop is greatly reduced in a small amt of time

Gene frequencies change according to those possessed by the survivors

18
Q

Gene Flow

A

Exchange of genes btw pops of the same species

Immigration/emigration