Exam 2

Question 1

Explain natural section, the requirements for natural selection (3 requirements),
and give an example of this process in nature

Answer 1

Natural selection is a non-random mechanism behind descent with modification and results in organisms being adapted to their environment over time.

Requirements：
1.variation: mutations - new genes or alleles sex - new combo of genes/alleles
gene flow - movement of genes/alleles from one population(group of individuals in particular area) to another
2. Differential reproduction(not all individuals survive reproduce equally well)
3. Heredity

1. Mutation must occur
2. Developmental constraints
3. More mutations are deleterious
4. Advantageous traits must have strong selective advantage
   Rock pocket mouse — color blends in perfectly(advantageous trait), dark color appears because of mutation(random event, variation), heredity(their parents DNA), different reproduction (reproduce a large amount)

Question 2

Discuss fitness

Answer 2

Fitness refers to the successfulness of one organism to pass on its genetic material to future generations. It includes surviving, finding a mate, mating, and reproducing. Ultimately the more viable young produced the fitter the organism. The numbers of advantageous traits changes your fitness.

Question 3

Define the biological species

Answer 3

Species is group of populations whose members have the potential to interbreed in natural and produce viable offspring but do not produce viable, fertile offspring with members of other such groups.

Question 4

Prezygotic

Answer 4

block fertilization from occurring (different species cannot offspring)(one of the reason
they cannot live in the same place, cannot meet the same time of the year, genetically incapable

Question 5

Postzygotic

Answer 5

hybrids not viable

Question 6

Allopatric speciation

Answer 6

different descents live in different habitat

occurs when populations are geographically isolated - natural selection, genetic drift

Question 7

Sympatric speciation

Answer 7

different descents live in the same habitat

occurs when populations are in same geographic area

Question 8

Describe factors that promote more biodiversity in a region

Answer 8

1. climate
   - warm and moist - fewer biotic challenges
   - Longer days year round - more photosynthesis
2. Topography
   - Altitudinal stratification
3. Competition - drives formation of species(‘specialists) (get pressure, so to specialise in a specific sources in order to not to compete)
4. Stability over time(fewer extinction events like ice ages)

Question 9

Species diversity

Answer 9

Species diversity: combines species richness and species evenness(Shannon Weiner Index)

Question 10

Species richness

Answer 10

number of species in a region/community

Question 11

Species evenness

Answer 11

relative abundances of species in a region/community compared with one another

Question 12

Niche

Answer 12

sum of species’ use of the biotic and abiotic resources in its environment Because if you know what one species eats and uses to survive and you know another species eats and uses to survive, you can compare if they will be in competition in resource. In other word, if their niches are compatible to each other and to the ecological niche, they can coexist and not compete.

Question 13

competitive exclusion

Answer 13

same species, do the same thing, one will extinct

Question 14

If niche is the same, it will have competitive exclusion —>resource partitioning —> character displacement

Answer 14

If niche is the same, it will have competitive exclusion —>resource partitioning —> character displacement

Question 15

resource partitioning

Answer 15

species eat the same food, so one will not have food to eat and trying to find some other food

Question 16

character displacement

Answer 16

led by resource partitioning and drives to evolution, species’ characteristic changed, which is they found other food to eat.

Question 17

Mutualism(+/+)

Answer 17

bees helps flowers to reproduce, flowers give bees food

Question 18

Commensalism(+/0)

Answer 18

birds stays in a large’s body and eat their ear-wack, but large animals do not need someone else to clean their ear.

Question 19

Facilitation(+/+ or +/0

Answer 19

Interaction between two species where a positive effect is incurred by at least one species, however species are not in intimate contact with one another
a beaver’s dam can be viewed as an extension of the beaver’s phenotype while at the same time a phenomenon that, by creating a pond, is helpful to other species (e.g., fish).

Question 20

Predation(+/-)

Answer 20

Wolves in the yellow stone park chase and eat elk

Question 21

Herbivory(+/-)

Answer 21

Caterpillar eats a leaf in a plant, but do not kill the plant

Question 22

Parasitism(+/-)

Answer 22

ticks live on dogs, they are living by drinking the blood of the host animal, but do not kill the host

Question 23

Describe life history traits and their trade-offs

Answer 23

An organism’s life history comprises the traits that affect its schedule of reproduction and survival (the age at which reproduction begins, how often the organism reproduces, how many offspring are produced per reproductive episode)

Question 24

explain how new species may arise

Answer 24

1.reproductive isolation
prezygotic and postzygotic (barriers prevent populations from occuring)
2. polyploidy individual - extra set of chromosome ( more common in plants)