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50 terms

Soph. Bio. Ch 3 and 5- Ecology

Sophomore biology- Ecology and Population growth
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Ecology
the scientific study of interactions among organisms and between organisms and their environment or surroundings (ecosystems).
Biosphere
anywhere on Earth where life exists
Biome
a group of ecosystems that have the same climate and similar dominant communities
Ecosystem
a collection of the organisms that life in a particular place and their nonliving environment
Community
all of the different populations that live together in a defined area
Population
group of individuals that belong to the same species and live in the same area
Species
a group of organisms that are similar and can breed and produce fertile offspring
Organism
one single member of a species
Autotrophs
organisms that can capture energy from sunlight or chemicals and use that energy to produce food; also known as producers.
Photosynthesis
process used by most autotrophs; creates food and oxygen from sunlight, carbon dioxide and water.
Chemosynthesis
process used by some autotrophs; creates food from carbon dioxide and inorganic molecules without light.
Heterotrophs
organisms that rely on other organisms for their energy and food supply; also known as consumers
Herbivores
eat only plants
Carnivores
eat only animals
Omnivores
eat both plants and animals
Detritivores
feed on dead plants and animals (detritus)
Decomposers
break down organic matter
Food chain
a series of steps in which organisms transfer energy by eating and being eaten
Food web
a diagram that links all the food chains in an ecosystem together to form a more realistic view of energy flow
Trophic level
each step in a food chain or food web
Ecological pyramid
a diagram that shows the relative amounts of energy or matter contained within each trophic level in a food chain or web. Three main types of pyramids are:
Energy pyramid
shows the relative amount of energy available at each trophic level.
Biomass pyramid
shows the total amount of living tissue within a given trophic level
Pyramid of numbers
shows the relative number of individual organisms at each trophic level
Biogeochemical cycles
how elements, chemical compounds, and water are passed from one organism to another and from one part of the biosphere to another
Evaporation
when liquid water absorbs energy and becomes a gas
Precipitation
when water falls from the sky as rain, snow, sleet, or hail
Transpiration
when water is given off through the stomata of plants' leaves as a byproduct of photosynthesis
Condensation
when gaseous water vapor loses energy and becomes a liquid
Runoff
when precipitation travels along the surface of the Earth until it reaches a body of water
Primary productivity
the rate at which organic matter is created by producers
Limiting nutrient
a single nutrient that either is scarce or cycles very slowly, limiting the growth of organisms in an ecosystem
Algal bloom
the sudden growth of algae in a body of water
Geographic distribution
the area inhabited by a population
Population density
the number of individuals per unit area
Growth rate
determined by the number of births, the number of deaths, and the number of individuals that enter or leave the population
Immigration
the movement of individuals into an area
Emigration
the movement of individuals out of an area
Exponential growth
the type of growth seen when a population grows at a constant rate; represented by a "J"-shaped curve
Logistic growth
when a population's growth slows or stops following a period of exponential growth; represented by an "S"-shaped curve
Carrying capacity
the largest number of individuals that a given environment can support
Limiting factor
a factor that causes population growth to decrease; ex. climate, predators, food availability, or humans.
Density-dependent limiting factor
limiting factors that effect a population only when the population density reaches a certain level and operate most strongly when a population is large.
Competition
occurs when two organisms attempt to use the same resource; can occur between organisms or between species
Predator-pray relationship
when one species eats another for food; one of the best forms of natural population control.
Density-independent limiting factors
limiting factors that affect all populations in similar ways, regardless of the population size.
Demography
the study of human populations
Demographic transition
the change in a population from high birth and death rates to low birth and death rates
Age-structure diagrams
models that help demographers predict future growth of populations by showing the number of individuals in each age category
Modeling
The process of using mathematical formulas to predict future events