Class notes
Biol 114 Essential Exam 3 Study Guide
- Course
- Biology 114
- Institution
- State University Of New York - Binghamton
Exam 3 Study Guide for Biol 114.
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Population Ecology:1. Demography/Life Tables
a. Demography=study of factors that determine the size and structure of a
population over time and to predict how a population will change in the future.
i. Involves the age classes, sex ratio, rates of immigration and emigration,
survivorship, mortality, and fecundity of a population.
b. Life Tables=summarize the probabilities that an individual age class will survive
and reproduce in any given year over the individual’s lifetime.
i. All the individuals that are born at the same time, and are thus represented
by an age class, are called a cohort.
ii. Variables of a life table:
1. x is the year in consideration
2. n is the number of the cohort remaining in the population
3. lx is survivorship
4. dx is mortality (essentially, lx – lx+1 = dx)
2. Survivorship Curves
a. Made by plotting log of the number of survivors vs age
b. Types of Survivorship curves:
i. Type 1= Large percentage of survivors throughout much of the
individual’s life time, followed by a rapid decline in individuals.
ii.
, iii. Type 2= Relatively constant decline in survivorship throughout the life of
the species.
iv.
v. Type 3= Having a low survivorship (high mortality) early in the life,
followed by a fairly high survivorship throughout the remainder of the
lifespan.
vi.
3. Fecundity
a. Fecundity= number of offspring an individual can have in its lifetime.
, i. Typically only refers to number of female offspring a female can have in
her lifetime due to females being the ones producing offspring and the
high-investment sex.
ii. Net reproductive rate of any one age-class is calculated by multiplying
Survivorship x Fecundity.
1. If the sum is <1.0 the population is getting smaller
2. = 1 staying same
3. >1 the pop is growing
4. Life History Traits
a. The cost of reproduction is higher mortality.
i. The more offspring produced the shorter the life said offspring will have.
ii. How an organism allocates energy and effort into these processes is
referred to as its life history.
iii. Individuals with high fecundity generally have low survivorship. Whereas
those with low fecundity are associated with higher survivorship.
Competition and Niche Space:
1. Competition
a. Competition= Individuals interacting where both sustain some cost (or potential
cost).
i. -/- interaction
ii. Competition is costly to both parties involved
iii. Types of competition:
1. Interspecific competition= between different species
2. Intraspecific competition= within the same species
2. Intraspecific Competition
a. Competition between individuals within a species
b. Major cause of density dependent growth of a population
c. GAS response= Physiological-based response system where short-term gains of
survival in high population density situations are paired with long-term costs.
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