Evolution and speciation

Question 1

Define evolution

Answer 1

A change in the heritable characteristics of a population over generation time

Question 2

Ways to track evolution

Answer 2

1. DNA and proteins
2. Selective breeding
3. Homologous structures

Question 3

What is convergent evolution and its consequence

Answer 3

Different species evolving similar traits independently. Convergent evolution results in analogous structures, meaning that they have independently evolved common traits which are anatomically different but serve the same purpose.

Question 4

Give an example of analogous structures

Answer 4

Bats, butterflies, and birds: wings.
Dolphins and sharks: fins

Question 5

Define speciation

Answer 5

The evolutionary process through which different populations evolve to become different species, splitting from a common pre-existing species.

Question 6

Opposite of speciation

Answer 6

Extinction

Question 7

What is speciation driven by

Answer 7

• Reproductive isolation: two populations of the same species are prevented from interbreeding geographically or behaviorally (gene flow is inhibited)
• Differential selection: natural selection acting differently on two populations

Question 8

Definition of polyploidy

Answer 8

The condition whereby an organism has more than two complete sets of chromosomes in all cells (> diploid).

Question 9

When does polyploidy arise

Answer 9

When an individual gains more than two sets of chromosomes from:
* Within a single species: autopolyploidy
* Two different species: allopolyploidy

Question 10

Advantages of polyploidy

Answer 10

• Allows otherwise infertile hybrids to carry out meiosis due to additional chromosomes
• Larger and more vigorous than their diploid parents
• Having more copies of each gene reduces the impact of negative mutations because of masking

Question 11

Nondisjunction

Answer 11

The failure of chromosomes to separate during meiosis

Question 12

Adaptive radiation

Answer 12

Rapid evolution of multiple species from a common ancestor because of natural selection

Question 13

Homologous traits

Answer 13

Traits that look and function differently while sharing structural similarities