Unit II: Population Ecology

Question 1

What is a survivorship curve?

Answer 1

graph of the number of surviving population members versus the relative age of the member

Question 2

What is a survivorship curve used for?

Answer 2

It is used to visualize and compare life histories

Question 3

Exponential Growth is density ___________.

Answer 3

independent

Question 4

What is Exponential Growth?

Answer 4

accelerating growth pattern seen in populations under conditions where resources are NOT limiting

Question 5

Exponential growth has an _____ population growth rate.

Answer 5

accelerating

Question 6

What is Population Growth Rate?

Answer 6

number of organisms added in each reproductive generation

Question 7

When does exponential growth occur?

Answer 7

It happens in nature when there is NO intraspecific competition, such as:
- new population
- after a bottleneck
- increase in resources
- decrease in predation

Question 8

How do you calculate exponential growth rate?

Answer 8

dN/dT = rN
(r = intrinsic rate of increase
N = population size
T = time
d = derivative)

Question 9

What do the values of r mean?

Answer 9

neg: decreasing N
0: zero population growth
pos: increasing N

Question 10

Why does the potential for growth vary among species?

Answer 10

This is because of the variation in Life History traits.
- high potential growth rate: r - selection strategy
- low potential growth rate: K - selection strategy

Question 11

What is Biotic Potential (max)?

Answer 11

maximal potential growth rate of a species

Question 12

How do you calculate maximum growth for a species?

Answer 12

dN/dT = rmaxN

Question 13

What is Logistic Growth?

Answer 13

leveling off of exponential growth due to limiting resources

Question 14

What is Carrying Capacity?

Answer 14

(K) number of individuals of a species that can be supported by the limited resources of a habitat

Question 15

As N approached K, the growth of the population ___.

Answer 15

slows

Question 16

On a graph, the Malthusian catastrophe passes the carrying capacity of the population size.

Answer 16

True

Question 17

How do you calculate logistic growth?

Answer 17

dN/dT = rmaxN * (K-N)/K

Question 18

All individuals have an _______, which shapes how individuals survive and reproduce

Answer 18

energy budget

Question 19

What is an Energy Budget?

Answer 19

allocation of energy resources for body maintenance, reproduction, and parental care

Question 20

Can you have both fecundity AND parental care?

Answer 20

no

Question 21

What is Fecundity?

Answer 21

potential reproductive capacity of an individual, which is usually measured in females due to asymmetry of sexes

Question 22

What is Parental Care?

Answer 22

investment by parents in the production, survival, and reproduction of offspring

Question 23

What are the typically trade-offs in life history traits (fecundity, parental care)?

Answer 23

you can have few offspring with high parental care or lots of offspring with low parental care

Question 24

What is the Type I survivorship curve?

Answer 24

high in seed/offspring size but low in seed/offspring amount/number

Question 25

What is the Type III survivorship curve?

Answer 25

low in seed/offspring size but high in seed/offspring amount/number

Question 26

What trade-off issues does the time of reproduction present?

Answer 26

Early Reproduction - allocate lots of energy to growth - greater chance that you survive to reproductive age Late Reproduce - slower growth, need to survive longer before reproducing - but if individuals survive to reproductive age they are more "mature"

Question 27

Reproduction is costly in terms of lifetime fitness as reproducing more offspring now reduces the ability to survive and reproduce later. True or False?

Answer 27

True

Question 28

There is no variation in how species allocate their energy budget to the number of times they breed. True or False?

Answer 28

False, there is variation.

Question 29

What is Semelparity?

Answer 29

life history strategy characterized by a single reproductive event followed by death

Question 30

What is Iteroparity?

Answer 30

life history strategy characterized by a multiple reproductive events during the lifetime of a species

Question 31

Describe r - selection life history (Type III survivorship).

Answer 31

1. high fecundity 2. low parental care 3. fast maturity 4. small body size 5. low disease/predator resistance 6. low survivorship/lifespan

Question 32

Describe K - selection life history (Type I survivorship).

Answer 32

1. low fecundity 2. high parental care 3. slow maturity 4. large body size 5. high disease/predator resistance 6. high survivorship/lifespan