ZOO 101 Ecology Flashcards

Population Density

N per area/volume

Population Dispersion

indiv spacing pattern within pop boundaries

Mark-Recapture Method

sampling technique to est pop size; N = sn/x

Dispersion Types

clumped, uniform, random

Clumped Dispersion

indivs in patches; resource availability/behavior (most common)

Uniform Dispersion

evenly spaced indivs; antagonistic interactions/territoriality

Random Dispersion

unpredictable spacing; w/o strong attractions/repulsions

Demography

study of pop vital statistics (birth/death/migration) & changes over time

Life Table

summarizes survival & reproductive rates of specific age-groups (cohorts)

Type I Survivorship Curve

low early/mid death rate, > late death rate

Type II Survivorship Curve

constant death rate over lifespan

Type III Survivorship Curve

>/< early/late death rate

Exponential Population Growth

pop growth under ideal/unlimited env -> J-shaped curve

Intrinsic Rate of Increase (r)

per capita rate of pop growth at each instant in time

Exponential Growth Equation

dN/dt = rN

Carrying Capacity (K)

max env sustainable pop #

Logistic Population Growth

per capita growth rate -> 0 as pop nears K -> S-shaped curve

Logistic Growth Equation

dN/dt = rN((K - N)/K)

Life History

traits affecting reproduction/survival schedule (when/how often/how many)

Semelparity

1-time "big-bang" reproduction -> death

Iteroparity

rep repro over lifespan

Reproductive Trade-offs

lim resources -> compromise btwn offspring # vs provisioning/parental care

K-Selection

selection for traits advantageous at high pop density (near K)

r-Selection

selection for traits maximizing reproductive success at low pop density (un-crowded)

Density-Independent

birth/death rate !change w/ pop density

Density-Dependent

birth/death rate changes w/ pop density -> - feedback

Density-Dependent Regulation Mechanisms

resource competition, territoriality, disease, predation, toxic wastes, intrinsic (hormonal) factors

Population Dynamics

biotic/abiotic interactions -> pop # fluctuations ot

Population Cycles

regular boom-and-bust fluctuations

Metapopulation

local pops linked by immigration/emigration

Demographic Transition

shift from high birth/death rates to low birth/death rates

Age Structure

relative # of indivs of each age in a pop -> future growth trends

Ecological Footprint

aggregate land/water area req to produce resources consumed & absorb waste

Density Estimation Methods

sample plots, indicators (nests/burrows/tracks/feces), mark-recapture

Molecular Demographics

PCR/genetic profiles -> track individual reproduction w/o disturbance (e.g., loggerhead turtles)

Stair-Stepped Survivorship

brief periods of > mortality followed by < mortality

Population Size Change Equation

dN/dt = Births + Immigrants - Deaths - Emigrants

Logistic Model Caveat

assumes instantaneous adjustment to K; reality -> time delay -> temporary K overshoot

Metapopulation Dynamics

balance of local patch extinctions & immigrant recolonizations

Metapopulation Genetics

heterozygote advantage -> > flight -> > new patch colonization

Zero Population Growth Configurations

high birth rate - high death rate / low birth rate - low death rate

Infant Mortality

infant deaths per 1,000 live births; high rate -> parents + reproductive rate to compensate

Life Expectancy at Birth

predicted avg lifespan; recent < driven by disease (AIDS) & social upheaval

Demography Focus

often ignores males -> tracks only females giving rise to new females

Mark-Recapture Assumption

marked/unmarked individuals have = probability of capture; marked fully mix back in; no births/deaths/migration during interval

Conservation Logistic Model

used to estimate critical pop size below which endangered species may become extinct

Offspring Trade-off (Plants)

many small seeds for far wind dispersal / few large seeds w/ > endosperm nutrients for establishment

Density-Dependent Predation

> prey pop -> < hiding spaces -> + predation death rate

Density-Dependent Intrinsic Factors

high density -> aggressive interactions/hormones -> delayed sexual maturation & - immune system even if food is abundant

Human Pop Growth Rate

peaked at 2.2% in 1962; < w/ China famine; currently <

Age Structure Consequences

bottom-heavy -> rapid growth & future employment/education problems (e.g., Zambia) / small-base -> fewer working-age people to support retired "boomers"

Global Hectare (gha)

unit of biologically productive area; sustainable limit = 1.7 gha/person, but US avg = 8 gha/person ->unsustainable

Interspecific Interactions

competition, exploitation, positive interactions

Competition (-/-)

diff species individuals use same limiting resources -> < survival/reproduction

Competitive Exclusion

1 species uses resources > efficiently -> local elimination of inferior competitor

Ecological Niche

specific set of biotic & abiotic resources an organism uses

Resource Partitioning

niche differentiation -> enables ecologically similar species to coexist

Fundamental vs. Realized Niche

potential niche vs portion actually occupied (due to competition)

Character Displacement

sympatric pops diverge > in morphological traits than allopatric pops

Exploitation (+/-)

1 species benefits by feeding on/harming other (predation, herbivory, parasitism)

Aposematic Coloration

warning coloration (e.g., poison dart frog) -> + predator avoidance

Cryptic Coloration

camouflage -> makes prey difficult to see

Batesian Mimicry

harmless species mimics harmful species

Müllerian Mimicry

2+ unpalatable species mimic each other

Herbivory (+/-)

herbivore eats plant/alga parts -> harms !kills

Parasitism (+/-)

parasite derives nourishment from host -> host harmed

Endoparasites / Ectoparasites

live within host body / feed on external host surface

Positive Interactions (+/+ or +/0)

1+ species benefits & neither harmed

Mutualism (+/+)

interaction benefits both species

Commensalism (+/0)

interaction benefits 1 species & !harms/helps other

Species Diversity

variety of diff organisms; species richness + relative abundance

Species Richness

# of diff species in community

Relative Abundance

proportion each species represents of all individuals

Diversity Benefits

> productivity/biomass, > stability, > resistance to introduced species

Biomass

total mass of all organisms in habitat

Food Web

linked food chains diagramming trophic relationships

Energetic Hypothesis

food chain length limited bc energy transfer inefficiency (~10% transferred)

Foundation Species

highly abundant/large species w/ strong community effects (e.g., trees)

Keystone Species

!abundant but exert strong control via pivotal ecological roles (e.g., sea stars)

Ecosystem Engineers

species that dramatically alter physical env (e.g., beavers)

Bottom-Up Control

nutrient supply/lower trophic levels limit higher trophic level abundance

Top-Down Control

higher trophic level consumers limit abundance of lower trophic levels (trophic cascade)

Nonequilibrium Model

communities constantly changing post-disturbance

Disturbance

event (storm/fire/human) removing organisms or altering resource availability

Intermediate Disturbance Hypothesis

moderate disturbance levels -> > species diversity than low/high levels

Ecological Succession

predictable species replacement sequence post-disturbance

Primary Succession

begins in lifeless area w/o soil (e.g., glacial moraine)

Secondary Succession

recolonization post-disturbance where soil remains (e.g., post-forest fire)

Succession Processes

early species can facilitate, inhibit, or tolerate later arriving species

Latitudinal Gradients

tropics have > species diversity due to older evolutionary history & > climate/evapotranspiration

Species-Area Curve

> geographic area -> > species # (more diverse habitats/microhabitats)

Island Equilibrium Model

species # balance between new immigration & existing extinction

Island Equilibrium Factors

immigration < & extinction > as species # +; island size & distance from mainland determine rates

Pathogen Impact

highly virulent in new habitats bc new hosts lack evolutionary resistance

Zoonotic Pathogens

diseases transferred from animals to humans (3/4 of emerging human diseases)

Vector

intermediate species (e.g., ticks/mosquitoes) transferring zoonotic pathogen to humans

Plant Herbivory Defenses

physical (thorns/spines) & chemical (strychnine/nicotine/tannins)

Parasite Behavior Modification

parasite alters host behavior to > chance of reaching next host (e.g., infected crustacean leaves cover)

Shannon Diversity Index (H)

H = -(pA ln pA + pB ln pB + …); higher H = > community diversity

Molecular Diversity Tools

PCR amplifies ribosomal DNA -> gel electrophoresis -> generates DNA profile for invisible microbes