Unit 2 Exam Review: Evolution

Question 1

Why do organisms adapt and change?

Answer 1

To survive in their environment, reproduce effectively, compete for resources, respond to environmental shifts, utilize genetic diversity and evolve over time.

Question 2

What are the 3 types of mutations?

Answer 2

1. Beneficial mutations
2. Neutral mutations
3. Harmful mutations

Question 3

How can mutations lead to adaptations?

Answer 3

Mutations can lead to adaptations through the process of natural selection.

Question 4

What is mutation?

Answer 4

Mutation are random changes in the DNA sequence of an organism. These changes can occur spontaneously during DNA replication or due to exposure to mutagens.

Question 5

What are the 4 types of natural selection?

Answer 5

1. Stabilizing selection
2. Directional selection
3. Disruptive selection
4. Sexual selection

Question 6

What is natural selection?

Answer 6

Natural selection is the process where organisms with traits better suited to their environment are more likely to survive and have offspring. This leads to these advantageous traits becoming more common in a population over time, helping organisms adapt to their surroundings.

Question 7

How can environmental changes lead to evolution of a species?

Answer 7

Environmental changes can lead too the evolution of species through several key mechanisms:
- natural selection
- adaptation
- genetic drift
- gene flow

Question 8

What supports Darwin’s theory of evolution?

Answer 8

Darwin’s finches.
Each finch evolved and developed different features to mire suited for their environment.

Question 9

Natural selection vs artificial selection

Answer 9

Natural selection is driven by environmental factors, while artificial selection is controlled by humans.

(Purpose) Natural selection optimizes traits for survival and reproduction in the wild, whereas artificial selection focuses on traits that benefit human purposes. (Breeding)

Question 10

Explain directional natural selection

Answer 10

Causes evolutionary change by favouring organisms which are different from the normal population.
Is common in artificial breeding, or can be caused by sudden change in the environment.
(Example : giraffes with longer necks can reach trees better than others, providing them with a competitive advantage in environments for food)

Question 11

Explain disruptive natural selection

Answer 11

Similar to directional selection, disruptive selection causes evolution to adapt organisms to environmental changes.
However, disruptive selection sometimes favours more than one trait.
(Example : finches could have long, or short beaks depending on where they live in the world or what they eat)

Question 12

Explain stabilizing natural selection

Answer 12

(Is the most common)
Limits evolutionary change by favouring the current population norm (the average)
(Example : human birth weights)

Question 13

Explain sexual natural selection

Answer 13

Relates to the competition for mates and the preferences of individuals for certain traits in potential partners.
(Example : female peacocks prefer males with larger, more vibrant tails, leading to the evolution of increasingly elaborate tail feathers through sexual selection)

Question 14

How does evolution occur without natural selection?

Answer 14

1. Genetic drift
2. Genetic bottleneck
3. Founder affect

Question 15

Explain genetic drift

Answer 15

• changes to allele frequency by chance events or disasters (seen in small populations)
• lost alleles decrease genetic diversity

Question 16

Explain genetic bottleneck

Answer 16

• loss of genetic diversity following an extreme reduction in population size (starvation, disease, human activities, or natural disasters)

Question 17

Explain founder effect

Answer 17

• small number of individuals leave a population and establish a new population
• the new population is small with limited diversity
  (Example : finches leaving South America and going to Galápagos Islands)

Question 18

What are the different patterns of evolution?

Answer 18

1. Adaptive radiation
2. Divergent
3. Convergent
4. Co-evolution

Question 19

What is adaptive radiation?

Answer 19

When one species quickly diversifies into many different species that adapt to various environments.
(Example : Darwin’s finches on the island evolved different beak shapes to eat different foods, showing how one species can change into many specialized ones over time)

Question 20

What is divergent evolution?

Answer 20

Two or more species that started as the same species become increasingly different due to environmental pressures.
(Example : monkey and a human)

Question 21

What is convergent evolution?

Answer 21

• two unrelated species that do not share a recent common ancestor become similar due to environmental pressures
• they develop analogous structures
  (Examples : shark, dolphin and penguins)

Question 22

What is coevolution?

Answer 22

• two species evolve simultaneously when the survival of one species is influenced by the other
• one or both species may become dependent on the other (symbiotic relationship)
  (Example : predator-prey relationship, flowering plants-pollinators)

Question 23

What is a species?

Answer 23

A group of organisms capable of inbreeding and producing fertile offspring under natural conditions

Question 24

What are the 2 types of reproductive isolation?

Answer 24

• pre - zygotic
• post - zygotic

Question 25

What are the 4 sections within pre - zygotic reproductive isolation (prevention of mating)

Answer 25

• geographic isolation
• habitat isolation
• temporal isolation
• behavioural isolation

Question 26

What are the 2 sections within pre - zygotic reproductive isolation (prevention of fertilization)

Answer 26

• mechanical isolation
• gametic isolation

Question 27

What are the 2 sections within post - zygotic reproductive isolation

Answer 27

• hybrid inviability
• hybrid infertility

Question 28

Geographic isolation

Answer 28

Geologic processes that separate members of a species
(Example : slowly emerging mountain ranges; island formations)

Question 29

Habitat isolation

Answer 29

Species that are adapted to different habitats in the same general location
(Example : garter snakes: same region - one lives in water, one lives on land)

Question 30

Temporal isolation

Answer 30

Species have evolved different mating rituals / behaviours
(Example : male eastern and westerns meadowlarks use different types of songs to attract mates)