Populations and Variation in Life History Strategies Flashcards
Population ecology
study of populations and their interactions with environment
Properties of a population
- Density
- Dispersion
- Demographics
Density
of individuals per unit area
Dispersion
pattern of spacing of individuals within boundaries of the population
a. clumped-individuals aggregated into patches
b. uniform-individuals are evenly spaced
c. random-individuals are spaced randomly
Demographics
study of vital statistics and how the change in a population over time death rate, birth rate, age class structure, sex ratio survivorship curve plots # of surviving individual at each age
cohort
group born at the same time (same age)
Survivorship Curve types
- low mortality of juveniles, high mortality in oldest individuals
- uniform death rates
- mortality high for juveniles, low mortality for older age classes
Life history
behavioral features that affect reproduction, survival, growth,etc
Life History Traits
- Age of sexual maturity
- size of adult
- fecundity
- # of reproductive cycles
- parental care
- longevity
Principle of Allocation
energy invested in one trait/characteristic can’t be used for another
Optimality Theory
if an organism has certain traits, they will be more or less successful than others in regards to fitness
Life History Strategies
Semelparity-produce many offspring once in life
Iteroparity (seasonal)
Iteroparity (continuous)
produce few offspring many times in life
K-selection
selection for traits that are favorable in high density conditions
r-selection
selection for traits that maximize reproductive success and are favorable in low density conditions
Phenotypic Plasticity
same genotype producing different phenotype depending on environmental conditions; triggered by abiotic and biotic factors
Traits that can be plastic
morphology
development
physiology
behavior
Optimal Litter Size
low litter sizes-put more energy into offspring and produce higher quality offspring
high litter sizes-put more energy into offspring, but produce lower quality offspring
Apparency Theory
more apparent plants will be more heavily defended since they have a higher risk of herbivory