Evolution: Patterns of Evolution

Question 1

What is divergent evolution?

Answer 1

Pattern of evolution in which once similar species ancestrally diverge/become increasingly distant. Occurs when populations change to environmentally adapt.

Question 2

What is convergent evolution?

Answer 2

Two completely unrelated species shate similar traits. Traits arise due to each species adapting to similar conditions.

Question 3

What is coevolution?

Answer 3

Evolutionary process in which two species of organisms that are tightly linked evolve together, each population responding to changes in the other population.

Question 4

What are 3 examples of coevolution?

Answer 4

1: Monarch butterfly and Milkweed - Milkweeds have toxin in their leaves, which when eaten, makes monarchs’ leaves more toxic, causing birds to evolve away from eating them.

2: Rough-skinned newts - Their predators (red-sided garter snakes) were immune to their poison, so they evolved to be more poisonous, vice versa, repeat

3:Antibiotics - Bacteria now resist most antibiotics, despite only being developed in the 1940’s. This causes pharma companies to persue new ones.

Question 5

What is gradualism?

Answer 5

The theory that states change occurs within lineage, slowly and steadily, before and after divergence. (Big changes occur from many small ones)

Question 6

What is punctuated equilibrium?

Answer 6

The theory that states that evolutionary history consists of long periods of stasis, or equillibrium, “punctuated” or interrupted by periods of divergence.

Question 7

What is macro and micro evolution?

Answer 7

Macro: Evolution on a large scale, resulting in large scale evolutionary change (eg; formation of a new species)

Micro: Change that occurs in the gene frequency from generation to generation. Within species. Accumlating changes potentially lead to the formation/splitting of a new species.

Question 8

What is the Hardy-Weinberg principle and what are its requirements?

Answer 8

Principle stating that under certain circumstances, the frequency of alleles in a population remins constant generation after generation.

Requirements:
1: No mutations
2: Random mating
3: Large population size
4: No natural slections
5:Isolation (No genes move in or out of the population.)

Question 9

What are the 6 causes of microevolution?

Answer 9

1: Mutations
2: Genetic Drift
3: Gene Flow
4: Non Random Mating
5: Sexual Selection
6: Natural Selection

Question 10

How do mutations cause microevolution?

Answer 10

They provide new alleles to a population. Some beneficial, some irrelevant, some harmful. Once irrelevant mutations potentially become useful depending on environment changes. Bacteria/Micro-organisms reproduce quickly therefore accumulating mutation in a short period of time assuming its advantageous.

Question 11

How doe genetic drift cause microevolution?

Answer 11

Changes in allele frequencies of a small population by random chance. Small populations receiving few minor changes affects the allele frequency of the whole population.

Bottleneck effect: natural disasters/harsh conditions often reduce populations to smaller numbers. This is not representative of the larger population.
Founder effect: A small number of individuals colonize a particular area. Founder (small) population does not represent the parent generation.

Question 12

How does gene flow cause microevolution?

Answer 12

Movement of alleles into or out of a population. Very significant factor is mobility, as greater mobility gives an animal greater migratory potential. Maintained gene flow between generations may amalgamation of gene pools and reducing genetic differentiations. Acts against speciation by recombining gene pools of two groups.

Question 13

What does gene flow do within populations? Across?

Answer 13

Within: May introduce new gene versions to populations, raising it’s genetic variation.

Across: By moving genetic material around, it can make distant populations genetically similar to one another and reducing speciation changes. Less gene flow between two species, better chances they evolve into two species.

Question 14

How does non-random-mating cause microevolution?

Answer 14

Inbreeding, self pollination, and mating with whomever is physically closest all reduce variation and diversity.

Question 15

How does sexual selection cause microevolution?

Answer 15

Males and females use various methods to identify and select a particular mate (Eg: scents, colour displays, combat, or sexual dimorphism. A.K.A certain traits make you more matable, just a form of non random mating.

Question 16

How does natural selection cause microevolution?

Answer 16

Selective forces such as predation, competition and disease has certain individuals become more likely to survive and reproduce than others.

Question 17

What are the 3 ways that natural selection affects the frequency of an inheritable trait?

Answer 17

1: Stabilizing selection - Favours intermediate phenotypes

2: Directional selection - Favours phenotypes at one extreme over the other, typically during environmental changes

3: Disruptive/Diversifying selection - Extremes are favoured over the intermediate

Question 18

How do human activities affect genetic diversity?

Answer 18

• May fragment habitats when converting wilderness expanses to croplands/wild areas
• Unregulated hunting, habitat remove, and other human actions may cause abrupt population decline
• Sudden loss of genetic diversity from prior leads to inbreeding, which mat cause declining fertility rates
• Populations lacking diversity are more susceptible to environment changes