Topic 12

Question 1

Resources are often limited so..

Answer 1

organisms must decide how to allocate time and energy to different activities through lifespan

Question 2

Allocation decisions

Answer 2

will affect an individuals fitness by influencing growth, reproduction and survival.

Question 3

Organisms will develop ..

Answer 3

allocation strategies over evolutionary time to adapt to abiotic and biotic conditions in their environment

Question 4

Trade off

Answer 4

increased allocation of time and energy to some activities results in a decrease allocation to other activities. increase in one thing means decrease in something else

Question 5

Life history trade off

Answer 5

growth and survival vs reproduction

Question 6

Reproductive effort

Answer 6

proportion of averrable resources that an individual allocates to reproduction through its lifespan

Question 7

Reproductive effort =

Answer 7

current and future productive output

Question 8

Future reproductive output =

Answer 8

survival + fecundity in future

Question 9

Lifetime reproductive success (LRS)

Answer 9

number of offspring produced throughout the lifespan on an individual

Question 10

Life history strategy

Answer 10

set of choices and decisions resulting in an individuals allocation to reproductive effort through its lifespan

Question 11

Life history traits

Answer 11

• Body size / growth
• Age at sexual maturity
• Number of reproductive events
• Number of offspring produced per event
• Offspring size
• Amount of parental care
• Senescence, programmed death

Question 12

Life history strategies integrates all of these traits in a way that maximizes ;;

Answer 12

fitness that is molded through natural selection by environmental constraints

Question 13

NO such thing as a perfect life history strategy which…

Answer 13

would result in unlimited production of viable offspring

Question 14

Body size /growth

Answer 14

general pattern: fecundity increases w body size. larger individuals have more resources to devote to offspring. body size w affect aspects of survival as well

Question 15

Maturity

Answer 15

general pattern: age maturity increases as adult lifespan or annual survival rate increase

Question 16

Long lifespan

Answer 16

high annual survival rate. current fecundity should not jeopardize future growth, survival and reproduction. favour growth in 1st few years to increase fecundity. favour reproduction over lifespan

Question 17

Short lifespan

Answer 17

low annual survival rate. current fecundity at the expense of adult survival (especially if semelparious) don’t favour growth and may die before breeding. favour current reproduction

Question 18

Birds

Answer 18

low annual survival-breed younger

high annual survival-breed older

Question 19

Semelparity

Answer 19

reproduce once and die

Question 20

Iteroparity

Answer 20

reproduce repeatedly throughout life span

Question 21

Semelparity occurs more..

Answer 21

for organisms living under variable environmental conditions

Question 22

Semelparity is favoured when

Answer 22

• Adult survival is low (lifespan < 1-2 years)

- Adult survival is high –but long intervals between years with conditions suitable for high offspring survive

Question 23

Mayflies (fishflies) semelparity

Answer 23

• Adult life stage is short-lived lasting hours to a couple days
• Do not consume food as an adult
• Sole purpose is reproduction
• After copulation the female will go off to lay her eggs and die

Question 24

Agaves semelparity

Answer 24

inhabit climates w erratic rainfall. plants store nutrients and grow for several years (25 years) reproduce during unusually wet year cause seeds have higher changer on establishment and parents die after flowering

Question 25

Salmon

Answer 25

fish grow rapidly at sea for years, huge effort to migrate up river to reach spawning grounds and during spawning migration females convert a larger portion of body tissue into eggs and reproduce and die shortly after spawning

Question 26

Fecundity

Answer 26

general pattern: as more offspring are produced the survival of each offspring decreases

Question 27

Fewer offspring

Answer 27

allocate more rescuers per offspring

Question 28

More offspring

Answer 28

allocate less resources per offspring

Question 29

Allocation to offspring

Answer 29

lots of ways in which parents can devote resources to offspring

Question 30

Oviparous

Answer 30

eggs provided with yolk hatch externally

Question 31

Ovoviviparous

Answer 31

eggs provided w yolk hatch internally

Question 32

Viviparous

Answer 32

nutrition provided directly by mother; live birth

Question 33

Resource based

Answer 33

different life history strategies are favoured under varying abundances of resources

Question 34

If resources are abundant

Answer 34

low competition amount individuals, population growth is at its max. Reproduction >> growth/survival = r-selected

Question 35

Abundant resources have large reproduction allocation but ..

Answer 35

invest little in survival

Question 36

If resources are limited

Answer 36

high competition amount individuals, population growth is low. population at carrying capacity. adaptations will enhance competitive ability. Growth//survival >>reproduction = K-selected

Question 37

Limited resources have large allocation to survival but...

Answer 37

little in reproduction