Ch. 9 Lecture

Question 1

Life History

Answer 1

life time pattern of GROWTH, DEVELOPMENT, and REPRODUCTION

Question 2

Questions we ask about life history

Answer 2

• What age do individuals mature and reproduce?
• How many offspring are produced over a lifetime?
• How long do individuals live?

Question 3

Life History Traits= ?

Answer 3

fitness components

Question 4

What do we measure?

Answer 4

life history traits = fitness components

(SMORRGL)

• Size at birth
• Maturity (Age and Size)
• Offspring (Number, Size, and Sex)
• Reproductive Effort (Age-, Stage-, or Size-Specific)
• Rates of Survival (Age-, Stage-, or Size-Specific)
• Growth pattern
• Lifespan

Question 5

Reproductive success influences populations!!!

Answer 5

Reproductive success influences populations!!!

Question 6

The evolution of life histories involves…

Answer 6

trade-offs

Question 7

What causes trade-offs in life history traits?

Answer 7

compensating for environmental variation is metabolically costly

Question 8

Reproductive Effort

Answer 8

total energetic cost of reproduction per unit time

Question 9

Herbaceous perennials reproductive effort

Answer 9

15-20% net production

Question 10

Corn reproductive effort

Answer 10

35-40% net production

Question 11

Common lizard reproductive effort

Answer 11

7-9% annual energy

Question 12

Allegheny Mountain Salamander reproductive effort

Answer 12

48% annual energy

Question 13

How does an organism distribute its limited resources?

Answer 13

• reproduce early v. later in life
• produce many smaller v. fewer larger offspring

Question 14

What imposes trade-offs?

Answer 14

• Physiology
• Energetics
• Physical environment
• Biotic environment

Question 15

Parental Care

Answer 15

Altricial v. Precocial

Question 16

Altricial

Answer 16

require LONGER parental care because young are born somewhat HELPLESS

Question 17

Precocial

Answer 17

require no or VERY LITTLE parental care because young are born relatively MATURE

Question 18

Reproduction involves benefits and costs: Hypothesis

Answer 18

Behavioral, physiological, and energetic activities involved in REPRODUCTION REDUCES future reproductive success in the form of reduced SURVIVAL, FECUNDITY, and/or GROWTH.

Question 19

fecundity

Answer 19

actual reproductive rate measured by number of gametes produced

Question 20

age v. fecundity

Answer 20

age of reproductive maternity is a key aspect of life history. as age increases, cumulative number of offspring increases.

Question 21

Cost of delaying reproduction

Answer 21

predation

Question 22

extrinsic factors that can influence age of reproductive maturity and annual reproduction

Answer 22

• winterkill
• predation
• reabsorb fetus if conditions unfavorable/dominant male present

Question 23

Phenotypic Plasticity

Answer 23

ability of an individual to change form under different environmental conditions

Question 24

trade-offs between number and size of offspring

Answer 24

each offspring takes resources, which are limited.

-size at birth v. survivorship

Question 25

timing v. number of reproduction

Answer 25

semelparous v. iteroparus

Question 26

semelparous

Answer 26

reproduces once in life and then dies (insect)

Question 27

iteroparus

Answer 27

reproduces multiple times over a life time (shark)

Question 28

organizing life history traits

Answer 28

k-selected v. r-selected species

Question 29

r-selected species

Answer 29

- small size - fast development - reproduces early in life - many small offspring - fast pop. growth rate - no parental care - weak competitive ability - variable pop. size, below carrying capacity - variable and unpredictable mortality

Question 30

k-selected species

Answer 30

- large size - slow development - long lived - reproduces later in life - few large offspring - slow pop. growth rate - parental care - strong competitive ability - constant pop. size, close to carrying capacity - constant and predictable mortality

Question 31

r-selected-\>k-selected spectrum

Answer 31

bacteria \> mollusks \> insects \> fish \> amphibians \> reptiles \> mammals \> humans