28: Reproductive Strategies

Question 1

What is logistic growth?

Answer 1

A type of population growth that follows an S-curve
- rapid increase in size when the population is small but as it becomes larger, the rate of increase goes down until it levels off

Question 2

What is carrying capacity on a logistic growth curve?

Answer 2

where it levels off

Question 3

What is biotic potential on a logistic growth curve?

Answer 3

slope of a line where the population growth is unrestricted

Question 4

What are k-selected species (k-strategists)?

Answer 4

populations that tend to stabilize over time near carrying capacity
- probably stay leveled off at the carrying capacity part of logistic growth
- they maximize survival

Question 5

What are examples of k-selected species (k-strategists)?

Answer 5

elephant, oak tree

Question 6

What are r-selected species (r-strategists)?

Answer 6

populations that have a high biotic potential
- they invest their energy in producing lots of offspring in a very short time
- they maximize reproduction

Question 7

What are examples of r-selected species (r-strategists)?

Answer 7

cockroach, dandelion

Question 8

What is survivorship?

Answer 8

percentage of a cohort that survives at certain age
- how many of them manage to survive at a certain age?

Question 9

What is a cohort?

Answer 9

group of individuals all born at the same time

Question 10

What is the x-axis of a survivorship curve?

Answer 10

1. lifespan
2. age
3. time
4. pre-reproductive age, reproductive age, and post-reproductive age
5. percentage

Question 11

What is the y-axis of a survivorship curve?

Answer 11

number of survivors

Question 12

Is a survivorship curve in logarithmic scale?

Answer 12

yes

Question 13

What are the 3 theoretical survivorship curves?

Answer 13

1. type I: Late Loss
2. type II: Constant Loss
3. type III: Early Loss

Question 14

What is a type I: late loss survivorship curve?

Answer 14

starts with a thousand living individuals, little infant mortality (death), most reach old age and then many die at the same time
- most of the deaths occur late in life

Question 15

What is an example of an organism in a type I survivorship curve?

Answer 15

humans

Question 16

What is a type II: constant loss survivorship curve?

Answer 16

chance of death is constant all along the life span
- populations where individuals die in accidents usually

Question 17

What are examples of organisms in a type II survivorship curve?

Answer 17

squirrels, birds

Question 18

What is a type III: early loss survivorship curve?

Answer 18

a lot of infant mortality, lots of deaths in the first stages of life

Question 19

What are examples of organisms in a type III survivorship curve?

Answer 19

clams

Question 20

What type of survivorship curve do you expect to see in an r-selected species?

Answer 20

type 3: early loss

Question 21

What type of survivorship curve do you expect to see in a k-selected species?

Answer 21

type 1: late loss

Question 22

Who is more likely to become endangered (or extinct): a k-selected species or an r-selected species?

Answer 22

k-selected species since they produce fewer offspring and breed less frequently