module 10 Flashcards
Intrinsic Rates of Increase
which size of animal has larger intrinsic rates of increase
On average, small organisms have higher rates of per capita increase and more variable populations than large organisms.
increase intrinsic rate of increase
increase organism size
small organisms live a shorter lifetime need to be replaced more
large organisms take up more resources
Life History
interplay between
based on
Organism’s lifetime pattern of growth, development, and reproduction
Interplay between:
- Fecundity – # of Offspring it produces
- Its Survival
- Size & Age at Reproductive Maturity
Based on Evolutionary Context
What is the best way to live life in order to maximize the number of offspring that eventually Breed?
Principle of Allocation
what has fixed energies
leads to
If organisms use energy for one function, the amount of energy available for other functions is reduced.
- Growth
- Maintenance————have fixed energy
- Reproduction
Leads to trade-offs between functions
Trade-offs of life history include
- Mode of reproduction
- Age at first reproduction
- Allocation to reproduction
- Number and Size of eggs, young, or seeds
- Timing of reproduction
-Trade-offs imposed by physiological, energetic, and environmental constraints
female size and eggs
-large # of eggs= ____ gene flow
female size increases
produce larger eggs- smaller amount of eggs produced
greater gene flow
larvae from larger eggs hatch
- Larvae from larger eggs hatch earlier
- Feed earlier-not a lot of competition a lot of resources available
- Grow faster
- Don’t drift as far
- Do not disperse great distances.
- Greater isolation ->rapid gene differentiation.
- other measures of reproductive output
- recruitment success definition
- larger seeds produce ______ seedlings
Fertility Rate -> Fecundity Rate -> Birth Rate ->
- Recruitment success. (best measure)
- -Addition of new, breeding individuals into population through reproduction
- -Seed size variation explains variation in Plants
- -Larger seeds produce larger seedlings
seed masses (seed size) increase, seedling height small seed equals \_\_\_\_\_seedling recruitment
seedling height increases
- Larger seeds produced taller seedlings.
- -Energy reserve boosts seedling growth.
- -Rapid growth helps seedling penetrate thick litter layer.
-low seedling recruitment
Westoby et.al. recognized four plant form -graminoids forbs woody plants climbers
who produces larger seeds?
Recognized four plant forms:
- Graminoids: Grass and grass-like plants.
- Forbs: Herbaceous, non-graminoids.
- Woody Plants: Woody thickening of tissues.
- Climbers: Climbing plants and vines.
-Woody plant and climbers
–Produced 10 x’s the mass of seeds of either graminoids or forbs.
Evolutionary Context?
Westoby et.al. Recognized six seed dispersal strategies: unassisted adhesion wind ant vertebrate scatter hoarded
- Unassisted: No specialized structures.
- Adhesion: Hooks, spines, or barbs.
- Wind: Wings, hair, (resistance structures).
- Ant: Oil surface coating (elaisome).
- Vertebrate: Fleshy coating (aril).
- Scatterhoarded: Gathered, stored in caches.
Dispersal mode might influence seed size.
which is the largest seed?
unassisted
wind dispersed-small seed
scatter hoarded-largest
vertebrae dispersed-large seeds
Particular Environmental Factors Key
plants must become _____ in an environment
small plants produce _____ # of seeds
who has advantage in areas of high disturbance
-seed size set to _____ number of established young
Particular Environmental Factors Key
- Role of Competition & Disturbance
- Plants must become Established in Environment
- -Small plants producing large # of small seeds
- Advantage in areas of high disturbance.
- -Plants producing large seeds
- Constrained to producing fewer seedlings
- More capable of surviving environmental hazards & Competition
- Trade off between # of seeds & Successful Seeds
- -Seed size set to maximize number of established young
Natural Selection
Reduces Variability
Sexual Reproduction -increases what is \_\_\_\_ to individuals each offspring contributes to \_\_\_\_ to fitness finding mates is
- Increases Variability
- Costly to Individual
- -Each Offspring contributes ½ to fitness
- -Finding Mates & Copulation is hard
Asexual Reproduction
- Mutation only Variability
- Offspring Contribute wholly to fitness of parent
What is male and female ?
females produce
males produce
female reproduction thought to be limited by
male reproduction thought to be limited by
- Females produce larger, more energetically costly gametes.
- Males produce smaller, less energetically costly gametes
- Female reproduction thought to be limited by resource access.
- Male reproduction limited by mate access.
Hermaphrodites
Exhibit both male and female function.
Conditions favoring hermaphroditic populations:
- Low mobility
- -Limiting male:male competition.
- Low overlap in resource demands
- -By male and female structures.
- Sharing of costs
- –For male and female function.
hermaphrodism-Simultaneous
Both Sexual organs present at all times
Snails, worms
hermaphrodism- sequential
- One sexual function occurs, followed by the second
- Mollusks, Echinoderms, Some Fishes
- change sex throughout time
Dioecious plants
Separate male and female individuals
Hermaphroditic Plants
individuals with _____flowers
Individuals with perfect flowers, male (stamens) and female (ovaries) reproductive organs in the same flower
Monoecious
hermaphroditic and monoecious plants may or may not be able to
- Individuals with imperfect flowers
- -Separate male and female flowers on the same plant
- Hermaphroditic and monoecious plants may or may not be able to self-fertilize
Probability of future survival can be reduced by
no reproduction = _____mortality
reproduction=__________mortality
- mate acquisition
- defense of a breeding territory
- feeding and protection of young
low mortality
high mortality
Allocation to reproduction _______ allocation to growth
reduces allocation to growth in many plant and animal species
