Chapter 8

Question 0

Directional selection

Answer 0

Occurs when selection favours individuals with a more extreme variation of a trait
Common in artificial breeding horses larger faster
If a population of hummingbirds with varying bill lengths enters a new environment with long flowers -> long bills feed and live population is long billed

Question 1

Evolutionary change without selection

Answer 1

Not all evaluation art changes are a result of natural selection
Changes in genetic makeup of a population are not always influenced by the traits of an individual

Question 2

Stabilizing selection

Answer 2

Average phenotype is favoured by environment
Individuals that deviate from population average not selected
Hummingbirds varying bill lengths flowers medium medium bills selected
Humans babies 3kg survive better than +/-

Question 3

Disruptive selection

Answer 3

Favours individuals with variations opposite extremes over medium
Sometimes environment favours More than one phenotype
Two species of plants with different size flowers for large and small bills no medium

Question 4

Sexual selection

Answer 4

Favours any individual with a trait that enhances mating success
Animals: sexual dimorphism colours, antler size body size mating and courtship behaviour
Plants: flower colour and scent

Question 5

Genetic drift

Answer 5

A change in gene pool due to chance
All populations are subject to some genetic drift
The smaller the population the greater the impact of genetic drift
Bottleneck effect
Founder effect

Question 6

Bottleneck effect

Answer 6

Sudden reduction in population size alters gene pool. Causes Natural disasters and humans
When a population is reduced in size unlikely that all alleles are present in new population. Some alleles will be eliminated altogether

Question 7

Founder effect

Answer 7

Occurs when a small number of individuals separate from original population and establish a new one
Elle’s frequencies in new population will differ from original

Question 8

Both types of _______ will cause a decrease in the gene pool of new population

Answer 8

Genetic drift

Greatly impacts populations ability to adapt to environment changes

Question 9

As organisms evolve they do so on a large and small scale (synonyms)

Answer 9

Microevolution macroevolution

Question 10

Microevolution

Answer 10

When changes occur in gene frequencies & phenotypic traits

Question 11

Macroevolution

Answer 11

When large scale changes occur and new species form

Question 12

Speciation

Answer 12

Formation of new species from an existing one

Question 13

Reproductive isolating mechanisms

RIMs

Answer 13

When a new species becomes reproductively isolated which prevents gene flow from occurring

Question 14

Prezygotic mechanisms

Answer 14

A reproductive isolation mechanism that prevents interspecies (between) mating & fertilization
5 types
Behavioural, ecological, temporal, gametic, mechanical isolation

Question 15

Postzygotic mech.

Answer 15

Prevents maturation of zygote and reproduction in offspring produced from interspecies reproduction
3 types
Zygotic mortality, hybrid inviability, hybrid infertility

Question 16

Behavioral isolation

Answer 16

Different species use different courtship and other mating clues to find and attract a mate

Question 17

Ecological isolation

Answer 17

Different species breed at different times of the year

Question 18

Temporal isolation

Answer 18

Very similar species may occupy different habitats within a region

Question 19

Gametic isolation

Answer 19

Male gametes may not be able to recognize and fertilize and egg of a different species

Question 20

Mechanical isolation

Answer 20

Difference in morphological features may make two species incompatible

Question 21

Zygotic mortality

Answer 21

Meeting and fertilization or possible but gametic differences result in a zygote that is unable to develop properly

Question 22

Hybrid inviability

Answer 22

Hybrid individual develops but either before birth or is born alive can’t survive into maturity

Question 23

Hybrid infertility

Answer 23

Hybrid offspring remain healthy and viable but sterile

Question 24

Human evolution

Answer 24

Ardipithucus ramidus
Homo habilis
Homo sapiens

Question 25

Gradualism

Answer 25

Attributes a large evolutionary changes in species to the accumulation of many small and ongoing changes and processes

Question 26

Punctuated equilibrium

Answer 26

Attributes most evolutionary changes to relatively rapid spurts of change followed by long periods of little or no change

Question 27

Series of life’s creation

Answer 27

1Big Bang with evolution
2creationism God
3alien theory
4intelligent design