Unit 2: Evolution

Question 1

define evolution

Answer 1

the process of cumulative change in the heritable characteristics of a population

Question 2

what are the five points of Darwin’s theory of evolution

Answer 2

1. Populations produce more offspring than the environment can support
2. Variation exists within the population
3. Natural Selection; organisms who are more likely to access resources have a greater chance of passing their advantageous alleles down to the next generation over others at a disadvantage
4. Progressive Change; there are slow increases in the frequency of beneficial alleles making individuals better adapted to their environment

Question 3

What did Hutton contribute to Darwin’s theory

Answer 3

Hutton proposed uniformitarianism; the earth is formed through slow moving processes which will continue to shape it; much like the way species are always slowly changing through natural selection

Question 4

What did Lamarck contribute to Darwin’s theory

Answer 4

Lamarck hypothesized that through use, a species could further develop its existing traits so that they became more beneficial. However this is false as genes cannot change within a generation.

Question 5

What did Malthus contribute to Darwin’s theory

Answer 5

Malthus was an economist who suggested resources like food, water, and shelter were natural limits to human population growth; likewise, environments can only support so many individual species.

Question 6

What did Cuvier contribute to Darwin’s theory

Answer 6

Cuvier noticed the major differences in bone structure of different prehistoric elephants, suggesting those prior forms of elephants have gone extinct through catastrophism (major catastrophic events)

Question 7

What did Lyell contribute to Darwin’s theory

Answer 7

Lyell viewed that forces of geological change have always shaped species through a series of small, subtle changes.

Question 8

What is the gene pool

Answer 8

refers to all of the alleles in the individuals that make up a population

Question 9

What determines a population

Answer 9

same species, same place, same time

Question 10

explain what a niche is

Answer 10

a niche describes how an organism fits into its surroundings with its anatomical, physiological, and behavioral adaptations to those surroundings

Question 11

stabilizing selection

Answer 11

favors intermediate variant

Question 12

natural selection (microevolution mechanism)

Answer 12

environment selects certain traits over others

Question 13

disruptive selection

Answer 13

intermediate varieties removed

Question 14

sexual selection

Answer 14

sexual partner selects certain traits over others

Question 15

artificial selection, one example

Answer 15

humans select certain traits over others

Question 16

what is genetic drift, what are the two types

Answer 16

genetic drift is random change in the gene pool, bottleneck effect, founder effect

Question 17

describe the bottleneck effect

Answer 17

a disaster drastically reduces a population’s size causing an abrupt change to its allele frequencies

Question 18

describe the founder effect

Answer 18

a few individuals out of a population migrate to an isolated land and colonize, this new colony is less genetically diverse

Question 19

what is gene flow

Answer 19

the random process of the exchange of genes with another population

Question 20

macroevolution

Answer 20

major evolutionary change leading to the formation of new species

Question 21

what are the two types of prezygotic barriers

Answer 21

allopatric speciation, sympatric speciation

Question 22

what are the types of allopatric speciation

Answer 22

just geographic isolation

Question 23

what are the types of sympatric speciation

Answer 23

behavioral, temporal, and mechanical isolation

Question 24

geographic isolation

Answer 24

• a population is separated geographically due to geologic processes or migration
• new selective pressures within the new areas cause the population to diverge

Question 25

behavioral isolation

Answer 25

*individuals of a population diverge overtime due to having different courtship behaviors

Question 26

temporal isolation

Answer 26

*members of a population having differing breeding schedules causing the population to diverge

Question 27

habitat isolation

Answer 27

*individuals of a population adapt to different niches in the same location and diverge as a result

Question 28

mechanical isolation

Answer 28

*two seemingly similar species being unable to mate due to their reproductive structures being incompatible

Question 29

prezygotic vs postzygotic isolations

Answer 29

*prezygotic isolations are barriers preventing isolation while postzygotic isolations prevents the formation of fertile offspring (e.g. hybrid infertility prevents the formation of fertile offspring

Question 30

coevolution

Answer 30

*a species evolves in response to the evolutionary change of another

Question 31

divergent evolution

Answer 31

*related organisms become less and less alike and give rise to new species that are adapted to different environmental

Question 32

convergent evolution

Answer 32

• unrelated organisms that live in similar environments become more alike in appearance and behaviour due to similar adaptations made
• develop analogous structures

Question 33

analogous structure

Answer 33

-structures that have a different origin but have the same function

Question 34

homologous structure

Answer 34

-anatomically similar structures with different functions (e.g., human arm + hand v.s. bat wings)

Question 35

vestigial structure

Answer 35

remnant structures that no longer serve anything to an organism but has a function which was important to its ancestors

Question 36

what is the process called where the earth went from non-living to living?

Answer 36

abiogenesis

Question 37

what characteristics differentiate a prokaryote from a eukaryote

Answer 37

• no membrane bound organelles
• 70S ribosomes
• single-celled

Question 38

what is abiogenesis?

Answer 38

• how life started living on earth
• primitive earth was oxygen-free, and rich in gases, and had a large amount of energy its intense volcanoes, lightning storms, and UV radiation
• water, gases, and energy synthesized to create organic compounds which are the “building blocks of life”

Question 39

how do chemoautotrophs make food for themselves

Answer 39

-use chemicals and turns it into organic material for its own nutrition

Question 40

what is endosymbiotic theory

Answer 40

• explains the emergence of eukaryotic cells
• an aerobic prokaryote (which uses oxygen) became engulfed in another prokaryote, forming a mitochondria, altogether, a eukaryotic cell is made

Question 41

how do fossil records provide evidence for evolution

Answer 41

• fossils are well-preserved and their structures can be compared
• fossils can be aged so we can get a timeline out of them
• we can get DNA samples from fossils

Question 42

microevolution vs macroevolution

Answer 42

-microevolution explains how populations evolve leading to macroevolution which explains how new species are formed