1.3 Natural Selection

Question 1

Causes

Answer 1

Mutations, Meiosis, Sexual Reproduction/Random Fertilization

Question 2

Mutations

Answer 2

Add new alleles to the gene pool, some are harmful, some are not

Question 3

Meiosis

Answer 3

Produces gamete with unique combinations of alleles

Question 4

Sexual Reproduction/Random Fertilization

Answer 4

Unique offspring

Question 5

Results

Answer 5

1. Individuals will differ in the adaptations they have
2. Some will be better adapted to the environment than others

Question 6

Adaptations

Answer 6

Characteristics

Question 7

Competition

Answer 7

More individuals are born than can survive (overproduction of offspring)
Competition for food, water, territory, reproductive partners, to avoid predators etc.

Question 8

Adaptations, Survival, Reproduction

Answer 8

More favorable adoptions –> more likely to survive –> more likely to reproduce and pass on adaptations

Question 9

Selective Pressure

Answer 9

Evolutionary force that causes particular traits to be more favorable in certain environmental conditions

Question 10

Antibiotic Resistance

Answer 10

Mutated bacteria can survive in presence of antibiotics
Multiply –> Increase –> Spr

Question 11

Forms of Natural Selection

Answer 11

1. Directional
2. Stabilizing
3. Disruptive

Question 12

Stabilizing Selection

Answer 12

Selects for an intermediate phenotype
Extremes die, middle lives/grows
(Capybara, Human birth weight)

Question 13

Directional Selection

Answer 13

Favours on of two extreme phenotypes depending on the environment
Moves towards one of the extremes
(Giraffe neck length - longer = more food)

Question 14

Disruptive Selection

Answer 14

Faviurs extreme phenotypes and selects against an intermediate phenotype
Moves towards extremes, middle becomes less
(Oyster coloration)

Question 15

Environment

Answer 15

Surrounding/habitats that plants, animals and living organisms share

Question 16

Natural Selection

Answer 16

The process which drives evolution; where favorable types are selected for and unfavorable types are selected against

Question 17

Variation

Answer 17

The occurrence in an organism in more than one distinct color or form

Question 18

Heritable

Answer 18

When a characteristic is transmissible from parent to offspring through genes

Question 19

Allele

Answer 19

The form of a gene. E.g. if the gene is for “eye color”, then “blue” and “brown” are the different alleles

Question 20

Allele Frequency

Answer 20

The proportion of a particular allele variant of a gene present amongst a population’s gene pool

Question 21

Resistance

Answer 21

The natural ability to remain unaffected by agents in its environment. E.g. antibiotics or toxins