4 Flashcards
Ecology
The branch of biology that concerns interactions between organisms and their environments
Levels of biological organization
organism, population, community, ecosystem, biosphere.
Two principal pattern-based questions are
Where do organisms live?
How common or rare are they?
Two mechanistic questions
What factors determine the distribution of a species?
What factors determine the abundance of a species?
_________ patterns may be characterized
at a variety of spatial scales.
Distribution
Range sizes
Few species are widespread (and common); most species have small ranges (and are rare)
nonliving chemical and physical properties of an individual’s environment (e.g., temperature, light, water, nutrient availability, etc.)
abiotic components
all of the organisms that are part of an individual’s environment (e.g., predators, prey, competitors, mutualists)
Biotic compnets
Both abiotic and biotic factors may influence the ______ and _______ of a given species
distribution, abundance
Local factors, such as topography, proximity to water bodies, and etc., superimpose their effects on the climate of a terrestrial region to produce ___________ (e.g., weather)
Local abiotic conditions
__________ is the study of populations in relation to environment, including environmental influences on density and distribution, age structure, and population size
Population ecology
_____ is the number of individuals per unit area or volume
Density
______is the pattern of spacing among individuals within the boundaries of the population
Dispersion
______ is the influx of new individuals from other areas
Immigration
______ is the movement of individuals out of a population
Emigration
Environmental and social factors influence spacing of individuals in a population
patterns of dispersion
In a _____ dispersion, individuals aggregate in patches. This may be influenced by resource availability and behavior
clumped
A ______ dispersion is one in which individuals are evenly distributed. It may be influenced by social interactions such as territorially.
uniform
In a ______ dispersion, the position of each individual is independent of other individuals. It occurs in the absence of strong attractions or repulsions
Random
_________ is the study of the vital statistics of a population and how they change over time
Demography
Death rates and birth rates are of particular interest to _______.
demographers
A ________ is a graphic way of representing the data in a life table.
survivorship curve
What type of Survivorship curve is “low death rates during early and middle life, then an increase among older age groups”?
Type I
What type of Survivorship curve is “the death rate is constant over the organism’s life span”?
Type II
What type of Survivorship curve is”high death rates for the young, then a slower death rate for survivors”?
Type III
An organism’s ______ comprises the traits that affect its schedule of reproduction and survival
life history
List the life history traits
The age at which reproduction begins.
Survivorship to reproductive age.
How often the organism reproduces.
How many offspring are produced during each reproductive cycle.
Species that exhibit ______ or _______ reproduction, reproduce once and die (all-in)
semelparity, or boom or bust
Species that exhibit _______ or ________ reproduction, produce offspring over multiple years (bet hedging)
iteroparity, or repeated
Variable or unpredictable environments likely favor ________ reproduction, while more stable, predictable environments may favor ______ reproduction
boom or bust, repeated
The ___________ describes population growth in an idealized, unlimited environment
exponential model
It is useful to study population growth in an _________.
________ help us understand the capacity of species to increase and the conditions that may facilitate this growth.
Idealized situations
This is the equation for what? Growth rate = B + I - D + E
Per Capita rate of increase. If immigration and emigration are ignored, a population’s growth rate (per capita increase) equals birth rate + immigration minus (-) death rate + emigration.
______________ occurs when the birth rate equals the death rate
Zero population growth
ΔN/ΔT=rN
Continuous population growth equation. where N = population size, t = time, and r = per capita rate of increase = birth – death