K-selected and r-selected species

Question 1

quantity > quality:
ex:
quality > quantity:
ex:

Answer 1

• r-selected species
• spiders
• k-selected species
• elephants

Question 2

what is the competition for resources like in k-selected species’ habitats?

Answer 2

usually relatively high

Question 3

what is the competition for resources like in r-selected species’ habitats?

Answer 3

usually relatively low

Question 4

k-selected species tend to be what?
(size, number, environment, parenting approach, maturing, life span, reproduction)

Answer 4

k-selected species tend to be:
- large
- have a few offspring per reproduction event
- live in stable environments
- expend significant energy for each offspring
- mature after many years of extended youth and parental care
- have long life spans/life expectancy
- reproduce more than once in their lifetime

Question 5

r-selected species tend to be what?
(size, number, environment, parenting approach, maturing, life span, reproduction)

Answer 5

r-selected species tend to be:
- small
- have many offspring
- expend or invest minimal energy for each offspring
- mature early
- have short life spans
- may reproduce only once in their lifetime

Question 6

r-selected vs k-selected species: size

Answer 6

k-selected species tend to be large
r-selected species tend to be small

Question 7

r-selected vs k-selected species: energy for offspring

Answer 7

k-selected species tend to expend significant energy for each offspring
r-selected species tend to expend or invest minimal energy for each offspring

Question 8

r-selected vs k-selected species: number of offspring

Answer 8

k-selected species tend to have few offspring per reproduction event
r-selected species tend to have many offspring

Question 9

r-selected vs k-selected species: environments

Answer 9

k-selected species tend to live in stable environments
r-selected species vary in their environments

Question 10

r-selected vs k-selected species: maturing

Answer 10

k-selected species tend to mature after many years of extended youth and parental care
r-selected species tend to mature early

Question 11

r-selected vs k-selected species: life spans and reproduction

Answer 11

k-selected species tend to have long life spans/life expectancy and reproduce more than once in their lifetime
r-selected species tend to have short life spans and may reproduce only once in their lifetime

Question 12

what is biotic potential?

Answer 12

refers to the maximum reproductive rate of a population in ideal conditions

Question 13

are reproductive strategies always r-selected or k-selected?

Answer 13

no, many species have reproductive strategies that are not uniquely r-selected or k-selected, or they change in different conditions at different times

Question 14

how are k-selected species affected by invasive species? what about r-selected species?

Answer 14

k-selected species are typically more adversely affected by invasive species than r-selected species, which are minimally affected by invasive species

Question 15

most invasive species are:

Answer 15

r-selected species

Question 16

k-selected and r-selected are:

Answer 16

reproductive strategies/approaches

Question 17

k-selected species are more likely to be:
r-selected species are more likely to be:

Answer 17

• disrupted by environment change or invasive species
• invasive

Question 18

do k-selected species have a high biotic potential?

Answer 18

k-selected species have a long lifespan and a long time to sexual maturity, so they have a low biotic potential, and thus a slow population growth rate

Question 19

do r-selected species have a high biotic potential?

Answer 19

r-selected species have a short lifespan and are quick to sexual maturity, so they have a high biotic potential, and thus a high population growth rate

Question 20

do r-selected species or k-selected species work better?

Answer 20

they both work because they are both just different approaches/strategies to accomplish the same goal: passing on their genes through reproduction

Question 21

what is a low biotic potential?

Answer 21

there is a low maximum reproductive rate

Question 22

why are k-selected species more likely to be affected by environmental disturbances?

Answer 22

in the case of disease or a natural disaster, it takes them longer to reach their original population size

Question 23

k-selected species examples:

Answer 23

birds, most mammals

Question 24

r-selected species examples:

Answer 24

insects, fish, plants

Question 25

why are r-selected species more likely to be invasive?

Answer 25

they can outcompete k-selected species for resources like food/water because their populations grow so rapidly

Question 26

k vs r
lifespan

Answer 26

k: long
r: short

Question 27

k vs r
time to reproductive maturity

Answer 27

k: long
r: short

Question 28

k vs r
number of reproductive events

Answer 28

k: few (but can reproduce many times)
r: many (although may only reproduce one)

Question 29

k vs r
number of offspring

Answer 29

k: few
r: many

Question 30

k vs r
size of offspring

Answer 30

k: large
r: small

Question 31

k vs r
parental care

Answer 31

k: present
r: absent

Question 32

k vs r
population growth rate

Answer 32

k: slow
r: fast

Question 33

k vs r
population regulation

Answer 33

k: density dependent
r: density independent

Question 34

k vs r
population dynamics

Answer 34

k: stable, near carrying capacity
r: highly variable

Question 35

r-selected species put more energy into:
instead of:

Answer 35

• producing offspring
• caring for them

Question 36

are species either k-selected or r-selected?

Answer 36

no, it’s a spectrum

Question 37

what are some examples of species that aren’t strictly k-selected or r-selected?

Answer 37

both hares (12/year) and frogs (200/year) have many offspring a year but care for them

Question 38

what are the risks of having high parental care?

Answer 38

the death of the parent means the death of the offspring

Question 39

are k-selected or r-selected species more likely to go extinct?

Answer 39

k-selected species are less likely to adapt and more likely go extinct while r-selected species are more likely to adapt and less likely to go extinct