W1 - Animal Behaviour (NS & Adaptation) [Dr. Madikiza]

Question 1

Types of selection? (2)

Answer 1

• Artificial selection (AS).
• Natural selection (NS).

Question 2

Artificial selection?

Answer 2

= process by which heritable traits (genetic basis) favoured by human actions become more common in successive generations.

Question 3

How do traits become common in successive generations through Artificial selection?

Answer 3

Humans “select” certain varieties of an organism over others, by implementing breeding programmes that cause one or more varieties to increase in frequency.

Question 4

AS attributes? (3)

Answer 4

• Happens at microevolutionary scales (microevolution).
• Has an endpoint in mind (as it is done by humans).
• Doesn’t care about increasing survival & reproductive success but focuses on what is desired by humans (eg, to see if a behaviour has a genetic basis).

Question 5

Eg of AS?

Answer 5

Dog breeder with poodles.

Question 6

Explain poodle eg?

Answer 6

If you want to produce a teacup poodles (Generation N), select individuals with similar traits to what you want from Generation 1 & Generation 2 breeds.

Question 7

NS?

Answer 7

=

Question 8

NS attributes according to Darwin? (5)

Answer 8

• Individuals differ in their morphology, physiology and behaviour (variation).
• Some of this variation is heritable.
• There is competition between individuals for scarce resources (food, mating partners, space).
• The best competitors will leave more offspring than others. These offspring will inherit their parents’ characteristics & through NS over generations will come to be adapted to their environment.
• If environment changes, then new variants will appear & so NS can lead to evolutionary change.

Question 9

NS attributes in general? (2)

Answer 9

• Has no endpoint in mind (as it is done by nature).
• Nature selects a trait/phenotype that is frequent, as long as the trait (good or bad) increases the survival & reproductive success of an organism at that period of time.

Question 10

NS summary? (4)

Answer 10

1) If one variety of a trait helps individuals to survive & reproduce better in their environment than another variety of the same trait,

                    AND

2) If the trait in question can be passed across generations,

                   THEN

3) NS is occurring!

4) Therefore, nature “selects” those traits that enhance reproductive success.

Question 11

Behaviour?

Answer 11

= a response to a stimulus that often has a genetic influence (via pathways, etc).

Question 12

NS criteria/prerequisites (How NS operates)? (3)

Answer 12

• Variation.
• Fitness consequences/Fitness benefits.
• Modes of inheritance.

Question 13

Variation?

Answer 13

= must be in the trait observed.

Question 14

Types of variation? (2)

Answer 14

• Genetic variation.
• Environmental variation.

Question 15

Genetic variation?

Answer 15

= variation that is caused by genetic differences in the trait.

Question 16

What causes those genetic differences in the trait? (3)

Answer 16

• Mutation.
• Genetic recombination.
• Gene flow/Migration.

Question 17

Mutation?

Answer 17

= any change in genetic structure/DNA sequence.

Question 18

Genetic recombination?

Answer 18

= process during cell division where pairs of chromosomes line up & “cross-over”.

Question 19

Gene flow/Migration?

Answer 19

= when genetic variants of a trait can also enter a population, whereby individuals migrate in from other populations.

Question 20

Environmental variation?

Answer 20

= variation that is caused by rapid changes in the environment.

Question 21

What causes those rapid changes in the environment? (2)

Answer 21

• Humans (perhaps by deforestation, poaching, etc).
• Global warming.

Question 22

Fitness consequences?

Answer 22

= when the observed variations in a trait must have fitness consequences.

Question 23

Fitness?

Answer 23

= the expected “contribution” of an individual to the next generation, relative to other individuals.

Question 24

Contribution?

Answer 24

= mean number of reproductively viable offspring that an individual produces.

Question 25

Types of fitness/”contributions”? (2)

Answer 25

• Direct fitness.
• Indirect fitness.

Question 26

Direct fitness?

Answer 26

= the direct contribution that you as an individual makes in producing reproductively viable offspring & that survive.

Question 27

Indirect fitness?

Answer 27

= the indirect contribution that an individual makes through taking care of their relatives to ensure the survival of the entire population (me helping you helps me in the end).

Question 28

Direct fitness + Indirect fitness =…?

Answer 28

Inclusive fitness.

Question 29

Modes of inheritance?

Answer 29

= when the observed variation in a trait can be transmitted from parents to offspring.

Question 30

Modes of inheritance attributes? (5)

Answer 30

• Without a mode of inheritance, fitness differences are washed away (as genes can’t be passed on).
• Genes are passed down from generation to generation.
• Many traits are known to be under some type of genetic control.
• Therefore, genes are an obvious mode of transmission (genetic transmission).
• Only traits with a genetic basis will be acted upon by NS.

Question 31

Adaptation?

Answer 31

= traits that allow individuals to survive & reproduce better than their competitors.

Question 32

Adaptation attributes? (2)

Answer 32

• NS produces adaptations, where adaptations are traits that provide individuals with the highest relative fitness in an environment.
• Not all existing traits are adaptive (non-adaptive traits).

Question 33

Non-adaptive traits?

Answer 33

= traits that do not contribute to the survival & fitness of an organism.

Question 34

How are non-adaptive traits maintained? (3) PLN

Answer 34

• Pleiotropy.
• Linkage.
• No maintenance of non-adaptive traits.

Question 35

Pleiotropy?

Answer 35

= when a single gene has multiple effects.

Question 36

Eg of Pleiotropy?

Answer 36

Certain gene in mice that produces short ears also produces fewer ribs.

Question 37

Linkage?

Answer 37

= when a non-adaptive gene may be located very close to a highly adaptive gene on the chromosome, therefore, a non-adaptive trait is carried with the adaptive trait.

Question 38

No maintenance of non-adaptive traits?

Answer 38

= when non-adaptive traits are selected out.