Exam 2 Review

Question 1

Why do species live where they do?

Answer 1

species are adapted to where they live

Question 2

Adaptation vs acclimation

Answer 2

Adaptation is acquisition of advantageous traits that can be passed on
Acclimation is temporary physiological response to an altered environment
Ex. getting tan in the summer is an acclimation, the ability to tan is an adaptation

Question 3

How are adaptations accumulated by species?

Answer 3

Natural selection: the process by which individuals with useful traits pass them on

Question 4

What are the requirements of natural selection?

Answer 4

Genetic variation and selective advantages within that variation

Question 5

Selective Pressure

Answer 5

Adaptations to changes in the environment
Ex. adapting to antibiotics
Any cause that reduces or increases reproductive success

Question 6

Habitat vs ecological niche

Answer 6

Habitat is the environment, ecological niche is both the environment and the role a species plays
Ex. a panda is a bamboo forest secondary consumer

Question 7

What two factors shape biomes?

Answer 7

Temperature and precipitation
Determine the plants that can live in an area, which determines the animals that can live there

Question 8

What are tolerance curves?

Answer 8

Tolerance curves are diagrams of where a species can and can’t survive-based on a single limiting factor, unusually abiotic like temperature

Question 9

What are the three zones in a tolerance curve?

Answer 9

Optimal-abundant species
Physiological stress-minimal species
Intolerance-no species

Question 10

Ecological Niche Model

Answer 10

Considers biotic, abiotic, and abiotic/biotic interactions

Question 11

What is a species ecological niche?

Answer 11

The combination of all of a species adaptations to biotic and abiotic factors-not a place

Question 12

What is the competitive exclusion principle?

Answer 12

No two species can occupy the same niche because of competition-someone has to shift their niche

Question 13

What are the two possible outcomes of competition between species A and Species B?

Answer 13

Rare=extinction of one species
Niche shift of one or both species by natural selection=coexistence

Question 14

In nature, is there more co-existence or competition among species?

Answer 14

More coexistence
More adaptation=more specialized=more specific niche

Question 15

Invasive/exotic species

Answer 15

They are introduced by humans, and they occupy the niche of native species without checks and balances
Ex. zebra mussels, stink bugs

Question 16

What is demographic transition?

Answer 16

Countries moving from rural to urban lifestyle, and birthrates decreasing

Question 17

What is population density?

Answer 17

Number of individuals in an area at a certain time

Question 18

5 factors that influence population densities

Answer 18

1. birth and death rates
2. sex ratios-most species have more females
3. age distribution-more children=higher birth rates
4. Reproductive strategies (r vs. k)
5. Geographic dispersal-immigration, migration, etc

Question 19

R adapted organisms vs K adapted organisms

Answer 19

R adapted: short life, rapid growth, many offspring
K adapted: long life, slow growth, high parental care

Question 20

Logistic (s-curve)

Answer 20

reaches the carrying capacity (k) and levels off

Question 21

J curve (exponential)

Answer 21

continuous, self-multiplying population growth

Question 22

What is a carrying capacity?

Answer 22

Symbolized by K, the maximum number of individuals that an environment can support in a healthy population, limited by density dependent and density independent factors

Question 23

Why do populations never reach their biotic potential?

Answer 23

Environmental resistance: factors that tend to reduce population growth rates (density dependent and density independent)

Question 24

Density dependent vs density independent factors

Answer 24

Density-dependent factors are linked to population size (more individuals=more pressure, disease, lack of food, etc)
Density-independent factors are outside of the population size (drought, floods, habitat loss)

Question 25

Limit cycles vs. chaotic cycles

Answer 25

Limit cycles are predictable changes along the carrying capacity, caused by density dependent factors like predation and competition
Chaotic cycles are unpredictable and random changes along the carrying capacity, caused by density independent factors like weather

Question 26

What are the parts (phases) of a growth curve?

Answer 26

1. Lag phase: initial slow population growth from lack of females, birth rates are still greater than death rates
2. Exponential growth phase: many overlapping generations leads to rapids population growth
3. Overshoot phase: population overshoots its carrying capacity
4. Dieback phase: result of overshoot phase, population dies back and goes back to carrying capacity
5. Change along carrying capacity

Question 27

What is the difference in the growth curves of r-adapted species and k-adapted species?

Answer 27

A) If a species is r-adapted, they are more likely to have a big overshoot and then a dieback because they have so many offspring
B) Lag time will be longer for k-adapted species and shorter for r-adapted

Question 28

What is the value of being able to predict population growth over time?

Answer 28

Management and conservation of those populations
The more we know, the better

Question 29

Why do populations need to have disease and predators?

Answer 29

To prevent them from going through boom and bust cycles
Boom and bust cycles cause populations to go out of control, like white tailed deer in Michigan. They didn’t have enough predators to provide density-dependent factors