Evolution (II)

Question 1

What are the 3 patterns of evolution?

Answer 1

Divergent evolution, Convergent evolution and coevolution

Question 2

What is Divergent Evolution?

Answer 2

Two or more species diverge from a common ancestor

Species once similar to ancestor diverge and evolve independently and uniquely

Question 3

what are the Results of Divergent Evolution?

Answer 3

Competition between species is minimized
New species diverge to fill specialized ecological niches

Given enough time, new species continue to evolve until most available resources are used

Leads to overall increase in biodiversity

Single species or group evolve to fill available ecological niches

Question 4

What is Adaptive Radiation?

Answer 4

A form of Divergent Evolution
Definition: single species evolves into a number of distinct but closely related species

Each new species fills a different ecological niche

Occurs because a new variety of resources becomes available (not being used by other species)

Question 5

What is Convergent Evolution?

Answer 5

When two different species evolve to occupy similar ecological niches

Question 6

What is Coevolution?

Answer 6

One species evolves in response to the evolution of another species
“Evolutionary Arms Race”
One species evolves and gains advantage while other species evolves to keep up

Question 7

What is speciation?

Answer 7

the evolutionary formation of a new species

Question 8

what is Allopatric Speciation?

Answer 8

Speciation due to geographic isolation (physical barrier)
Unable to exchange genetic information

Over many generations, population will become less and less alike

Question 9

What are the 2 types of speciation?

Answer 9

Allopatric

Sympatric

Question 10

What is Sympatric Speciation?

Answer 10

Speciation as a result of populations splitting into separate gene pools
- Leads to reproductive isolation

Within the same geographic area

Rarer than allopatric speciation

Question 11

Define Reproductive Isolating Mechanisms (RIMs)

Answer 11

Any behavioural, structural or biochemical trait that prevents individuals of different species from reproducing successfully together

Question 12

What are the 2 types Reproductive Isolating Mechanisms (RIMs)?

Answer 12

Prezygotic mechanisms: RIMs that prevent interspecies mating and fertilization before the zygote can even form

Postzygotic mechanisms: RIMs that prevent maturation and reproduction in offspring from interspecies reproduction after the zygote forms

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Question 13

What are the types of Prezygotic Mechanisms?

Answer 13

Ecological isolation (physical), Temporal isolation(time, Behavioural isolation, Mechanical isolation, Gametic isolation

Question 14

Ecological isolation (physical)

Answer 14

species occupy separate habitats or may live in the same habitat but do not encounter one another to reproduce

Question 15

Temporal isolation(time)

Answer 15

reproductive cycles or mating occurs at different times

Question 16

Behavioral isolation

Answer 16

species use different signals for attracting a mate (distinct mating rituals)

Question 17

Mechanical isolation

Answer 17

structural differences in reproductive organs can prevent copulation

Question 18

Gametic isolation

Answer 18

prevents fertilization at the molecular level by molecular markers

Question 19

what are the 3 Postzygotic Mechanisms?

Answer 19

3 ways to prevent hybrids from reproducing:

Zygotic mortality: zygote or embryo fails to develop properly
Hybrid inviability: offspring experiences an early death
Hybrid infertility: offspring becomes strong and fit but is sterile

Question 20

what is Mimicry?

Answer 20

In biology, it is resemblance of another organism in order to protect itself

It is a species “pretending” to be another species, so that predators will not try to hunt them

Organisms do not acquire these traits, but rather, are survivors after millions of years of natural selection in effect