LIFE 121 Exam 4

Anatomy

biological form; structure of an organism

Physiology

biological function; processes and functions of an organism

Organ

functional unit; may be involved in different organ systems due to having different tissue types

Homeostasis

steady-state; maintenance of internal balance

Negative Feedback

acts to reduce or dampen the stimulus; move stimulus toward normal range

Endocrine System

releases hormones to coordinate gradual changes effecting entire body

Nervous System

nerve cells transmit impulses along routes that cause immediate and rapid responses to the environment

Thermoregulation

process by which animals maintain an internal temp within a tolerable range

Ecology

study of interactions between organisms and the environment

Organismal Ecology

level of organism; anatomy, physiology, immunology, behavior, and individual interaction with environment

Population Ecology

interactions of individuals of the same species in an area; population size and factors that influence it

Community

group of populations of different species in an area

Community Ecology

interactions between species; community structure and organization

Ecosystem Ecology

community of organisms in an area and physical factors with which the organisms interact; energy flows and cycling

Landscape Ecology

connection between ecosystems; factors controlling exchanges of energy, materials, and organisms across multiple ecosystems

Glaciation

wipe out everything and leave topsoil; doesn’t happen in tropics which allows for more diversity

Climate

long-term prevailing weather conditions in an area (not the same as weather)

Seasonality

Earth’s tilted axis of rotation and annual passage around the sun; variation in day length, solar radiation, temperature, regional precipitation, wind patterns

Windward

precipitation (side airflow first hits)

Leeward

dry (air flows down)

Aquatic

characterized by the physical environment (light and heat energy availability)

Wetlands

water-saturated; low in dissolved oxygen; high capacity to filter dissolved nutrients and pollutants

Coral Reefs

formed from calcium carbonate skeletons of corals; require high oxygen levels; high invertebrate and fish diversity; remnants of living organisms (cnidarians)

Dispersal

movement of individuals away from centers of high population density or from their area or origin; contributes to global distribution of organisms

Biotic Factors

predation, herbivory, mutualism, parasitism

Sampling Techniques

estimate densities and total population size

Density

number or individuals per unit area or volume

Dispersion

a pattern of spacing among individuals within the boundaries of the population

Clumped Dispersion

aggregate in patches, most common, influenced by resource availability and behavior

Uniform Dispersion

even distribution, influenced by social interactions (territory)

Random Dispersion

position of each individual is independent of others, absence of strong attractions or repulsions

Demography

study of population’s vital statistics and how they change over time

Cohort

group of individuals of the same age, from birth to death

Survivorship Curves

plot proportion or numbers of cohort still alive at each age

Population Change

birth, death, immigration, emmigration

Population growth rate

growth rate = birth-death

Exponential Growth

population increase under idealized conditions (seen in new and rebounding environments); cannot be sustained for long

Carrying Capacity (K)

max population size an environment can support; varies with abundance of limiting resources

Logistic Growth Model

per capita rate of increase declines as carrying capacity is reached; useful for estimating possible growth; fits few real populations

Population Dynamics

mechanisms that regulate population density, influenced by life history traits

Life Histories

traits that affect an organism’s schedule of reproduction and survival (reproductive age, reproductive frequency, how many offspring are produced)

K-selection

selection for traits sensitive to population density

K-type Population

birth rates fall and death rates rise with population density

r-selection

selection for traits that maximize reproduction

r-type Population

birth and death rate don’t change with population density

Density-dependent Population Regulation

rates can have negative feedback regulating population growth

Competition

occurs in crowded populations (lower birth rates)

Waste

effect organismal growth

Predation

may increase with increasing population size due to predator preference for abundant prey species

Territoriality

can limit population density when space becomes a limited resource

Disease

pathogen transmission rates may increase with increasing population density

Intrinsic Factors

physiological factors like hormonal changes that appear to regulate population size

Metapopulations

local populations linked by immigration and emigration

Local Populations

occupy patches of suitable habitat surrounded by unsuitable habitat

Ecological Niche

organism’s ecological role/job, abiotic and biotic factors influence survival and reproduction

Interspecific Interactions

interactions among different species (competition, predation, herbivory, symbiosis)

Competition

individuals of different species compete for resources that limit growth and survival (leads to competitive exclusion and niche specialization)

Competitive Exclusion

two species competing for the same resource cannot coexist (more efficient will outcompete, reproduce, and eliminate competitor)

Fundamental Niche

niche potentially occupied

Realized Niche

portion of fundamental niche actually occupied

Predator Adaptation

find and identify prey, catch and subdue prey, behavior (pursue/ambush)

Prey Adaptation

behavioral defenses, morphological defenses, physiological defenses

Mullerian Mimicry

two unpalatable species mimic each other

Batesian Mimicry

harmless species mimics harmful one

Hebrivory

plants use chemical and defensive structures because they are not motile

Symbiosis

direct and intimate relationship between individuals of two or more species (parasitism, mutualism, commensalism)

Species Diversity

variety of different organisms in a community

Species Richness

number of different species in a community

Relative Abundance

proportional abundance of different species in a community

Diversity Index

used to compare diversity among communities

Trophic Structure

feeding relationships between organisms in a community, key factor in community dynamics

Food Chains

tropic levels from producers to top carnivores, transfer or food energy and nutrients from one level to the next

Food Web

branching food chain with complex tropic interactions, species may play a role at more than one tropic level

Dominant Species

most abundant/have highest biomass; removal from community may have negligible impact

Keystone Species

not usually abundant, but disproportionately exerts strong control on community structure through their niche; removal results in large impact

Ecosystem Engineers (Foundation Species)

influence physical environment

Bottom-Up Model

influence from lower to higher tropic levels in a community; presence/absences of mineral nutrients determines community structure, including abundance of primary producers

Top-Down Model

control comes from tropic level above; predators control herbivores which control primary producers

Disturbance (NOT BAD)

events (natural and human-associated) can create significant changes on structure and function of community

Non-Equilibrium Model

communities are constantly changing

Intermediate Disturbance Hypothesis

species richness vs disturbance intensity

Primary Succession

occurs in regions in which the soil in incapable of sustaining life

Secondary Succession

occurs where a community that previously existed has been removed; smaller-scale disturbances that did not eliminate all life and nutrients from environment

Biogeographic Factors

latitudinal gradients and climate, area effects

Latitudinal Gradients

tropical regions have more species abundance and diversity (evolutionary history and climate)

Area Effects

larger areas have a greater diversity of habitats

Islands

isolated, small in size

Ecosystems

all the organisms in a community, as well as the abiotic factors with which they interact

Ecosystem Dynamic Processes

energy flow and chemical cycling

Energy (E)

1). cannot be created or destroyed, only transferred or transformed (ex. solar radiation transformed into chemical energy by photosynthetic organisms)

2). every exchange increases the entropy of the universe (some E is always lost as heat and input from the sun is required for the maintenance of energy flow)

Chemical Cycling

chemical elements are continually recycled within ecosystems so matter cannot be created or destroyed

Primary Production (PP)

amount of light energy converted to chemical energy by autotrophs during a given time period (chemoautotrophs are primary producers in few ecosystems)

Energy Budgets

photosynthetic production sets the spending limit for an ecosystem’s energy budget

Gross Primary Production (GPP)

total PP measures as the conversion of chemical energy from photosynthesis per unit time

Net Primary Production (NPP)

GPP minus energy used by one-degree producers for autotrophic respiration (Ra)

amount of new biomass added in a given time period

Standing Crop

total biomass of photosynthetic autotrophs at a given time (not equal to NPP)

Limiting Nutrient

element that must be added for production to increase in an area (can be demonstrated by nutrient enrichment studies)

Secondary Production

amount of chemical energy in consumers’ food converted to new biomass during a given period of time

Production Effieciency

organism’s production efficiency is the proportion of energy stored in food that is not used for respiration

Trophic Efficiency

percent of production transferred from one trophic level to the next (usually about 10%)