Life history

Question 1

life history

Answer 1

the adaptations of an organism that influence aspects of its biology, such as the number of offspring it produces, its survival, and its size/age at sexual maturity

Question 2

Principle of allocation

Answer 2

if an organism allocates energy towards one function, such as growth/reproduction, it reduces the amount of energy it can spend on other things, like defense mechanisms

Question 3

What do costly traits signify

Answer 3

a high quality individual

Question 4

Coho salmon reproductive trade offs

Answer 4

redder salmon have easier access to fertilize eggs because red is hard to produce and it makes them look better.
less red salmon invest in faster sperm

Question 5

David Lack’s hypothesis

Answer 5

Selection favors clutch size with maximum surviving offspring. Accounts for trade offs b/t

• clutch size
• probability of individual survival
• how many survive

Question 6

Why didn’t Lack’s hypothesis prove to be true?

Answer 6

1. maximum clutch sizes reduced future reproductive fitness in the mother
2. Maximum clutch sizes reduced (reproductive) fitness in offspring
3. an individual’s maximum is not necessarily equal to that of the population

Question 7

What experiment did lack do?

Answer 7

He added an extra egg to a clutch and it reduced both the mother’s future reproductive fitness and that of the offspring

Question 8

Kiwi trade off

Answer 8

Giant egg
few offspring
invested in heavily

Question 9

European kestrals

Answer 9

trade off between survival and paternal care

Question 10

plant investment in seed size

Answer 10

Few large seeds = bigger, taller, stronger seedlings with increased recruitment

Many small seeds = advantage in areas of high disturbance

Question 11

r selection
(and example)

Answer 11

• high population growth rate (reproduce quickly)
• unpredictable environments
• better colonizers
• quickly harvest resources and reproduce, even if its inefficient
• e.g. tailless tenrec has 32 pups

Question 12

K selection

Answer 12

• efficient resource use
• predictable environments
• better competitors
• slow growth and slow to reproductive maturity
• high investment in offspring to yield big size
• use resources efficiently –> good for scarce resources

Question 13

Humpback whale

Answer 13

-loses 70% of blubber while feeding baby

Question 14

3 key components to life history

Answer 14

1. How many offspring per reproductive episode?
2. How often does organism reproduce?
3. What is the age of sexual maturity?

Question 15

semelparity vs iteoparity

Answer 15

semelparity = reproduce once then die (r selection)

iteoparity = reproduces multiple times (K selection)

Question 16

chambered nautilus

Answer 16

only iteoparous cephalopod spawner

Question 17

synchronous semelparity

Answer 17

cicadas that only come out once every 13 or 17 years

• all emerge, reproduce, and die in same year
• all individuals in population are the same age

Question 18

Salmon as a spawner

Answer 18

semelparous

• leave for ocean as a small fry
• return to natal ground to reproduce
• invest in MANY gametes

Question 19

Advantage of iteoparity

Answer 19

• Cole found that r was greater in iteoparous organisms whether 40 or 50 offspring were produced
• greatest value when survival of offspring is uncertain
• tend to be iteoparous when adult survivorship is high
• also, shorter pre-reproductive time increased r

Question 20

Reznick and Endler’s guppy experiment

Answer 20

• if predators focus on the young or there are no predators, then K selected syndrome
• if predators focus on adults, then r selected syndrome and faster reproduction

Question 21

Pumpkinseed fish

Answer 21

when adult survival was lower than juvenile, there was greater body mass put towards gonads (GSI)

Question 22

Opossums

Answer 22

-Mainland ones had higher predation, so their offspring aged and reproduced at quicker rates than the island ones

Question 23

snakes + lizards

Answer 23

higher survival rate lead to later maturity

Question 24

Lions

Answer 24

• males are evicted at 2 yrs old to go take over another pride
• females are therefore sexually mature by age 2

Question 25

Prime reproductive age

Answer 25

stags are the ones with the prime reproductive age as opposed to the female hinds

Question 26

Types of parental care

Answer 26

1. none
2. uni-parent
3. bi-parent

Question 27

No parental care

Answer 27

sea turtles, megapodes, praying mantis

Question 28

uni parent care

Answer 28

seahorses (male), seals, spiders, humpbacks

Question 29

bi-parental care

Answer 29

dung beetles, titi monkeys, birds

Question 30

Grimes Triangle

Answer 30

1. Ruderals (high disturbed habitat)
   - grow fast, makes seeds quick, r-select
2. Stress-tollerant (high stress, no disturbance)
   - grow fast, K select
3. competitice (low disturbance, low stress)
   - grow well, but eventually compete for resources