Fitness

Question 1

life history trade-offs

Answer 1

a fitness benefit in one life history trait is correlated with a fitness cost in another

Question 2

life history variants can alter:

Answer 2

1. resource uptake/processing
2. resource allocation

Question 3

semelparity

Answer 3

individuals reproduce once and then die
ex. annual plants, salmon, many insects

Question 4

iteroparity

Answer 4

reproduction is repeated, w/ different survival/reproductive rates

Question 5

R on life history table indicates

Answer 5

lifetime reproductive success

Question 6

r on life history table indicates

Answer 6

intrinsic rate of increase
r = ln(R)

Question 7

lx on life history table

Answer 7

probability of an organism reaching age x

Question 8

mx on life history table

Answer 8

average fecundity of female at age x

Question 9

lx mx on life history table

Answer 9

chance of reaching age x times average fecundity at age x - add up all values to find lifetime reproductive success R

Question 10

size stable population will have

Answer 10

R = 1
r = 0

Question 11

natural selection favors _____ reproduction in growing populations

Answer 11

earlier

Question 12

a shift to earlier reproduction will…

Answer 12

spread faster

Question 13

senescence

Answer 13

aging, sometimes referring to cells that stop dividing but don’t die

Question 14

earliest portion of each brood has a larger impact on population growth ->

Answer 14

less evolutionary pressure to extend the end of the reproductive window

Question 15

mutation accumulation

Answer 15

less selective pressure works to get rid of deleterious mutations that occur later in life, so mutations accumulate allowing disease onset in old age

Question 16

antagonistic pleiotropy

Answer 16

alleles that extend lifespan come at the expense of earlier brood sizes - extending lifespan is unlikely to be favored

Question 17

why do we have grandmothers?

Answer 17

selection may act on other parts of biological organization
grandparent orcas remember hunting grounds to lead the pod
grandmother humans help with midwifery, societal organization, conflict management, long-term cultural memory

Question 18

r-selected populations

Answer 18

rapid growth rate (r)
quickly expands in disturbed/low competition areas
less competitive once the environment gets crowded

Question 19

K-selected populations

Answer 19

more competitive at the ecosystem’s carrying capacity (K)
slower population growth even in low-density environments

Question 20

populations will evolve towards a brood size that

Answer 20

makes the best use of its resource acquisition and allocation

Question 21

examples of brood size

Answer 21

1. guppies in high predation areas evolved to reproduce earlier than those in low predation areas (shown by switching guppies from both habitats)
2. adding more eggs to a bird’s nest than its average brood size will decrease all its offspring’s fitness

Question 22

small body size:

Answer 22

can reproduce faster but makes fewer offspring

Question 23

large body size:

Answer 23

can make more offspring, but takes a longer time to reach reproductive maturity

Question 24

sequential hermaphroditism

Answer 24

advantageous when reproductive success increases with size to a greater extent in one sex than the other

Question 25

protogyny

Answer 25

organisms turn female, then male -> larger older males are more successful in competition, for mating and defending territory ex. bluehead wrasse fish

Question 26

protoandry

Answer 26

organisms turn male, then female -> larger females can produce more eggs ex. slipper shells - a large female carries many smaller males when she dies, the largest male changes to female and is big enough to produce many eggs

Question 27

example: if sequential hermaphroditic shrimp are fished more often when they are larger, how will they evolve?

Answer 27

likely they will evolve to reproduce earlier in life while smaller - be female first

Question 28

generalists

Answer 28

can utilize a variety of resources in a wide range of conditions

Question 29

specialists

Answer 29

may have traits to help them utilize a specific resource, at the expense of being able to utilize a variety of resources ex. flowerpiercer birds have hooked beaks making them most able to drink from a specific flower type

Question 30

specialist and generalist trends

Answer 30

can differ among populations within a species, sometimes reflecting how stable an environment is