ECOLOGY
Organization of Life
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Biosphere= planet Earth
Biome= ecosystems in a particular climate. Ex. Tropical rain forest.
Ecosystem= all living & nonliving things in an area at one time.
Community= all living things in a particular ecosystem.
Population= all living things of the same species in an ecosystem.
Individual= one organism.
◦ Key Terms:
◦ Biotic= living things
◦ Abiotic= nonliving things
Key Terms
◦ Habitat= the dwelling place where an organism seeks food and shelter.
◦ Niche= the role that an organism plays in its community, such as what it eats and
where it lives.
◦ Species= a group of similar organisms that can breed with one another to
produce fertile offspring.
Biomes
◦ Terrestrial (on land) biomes
◦ Tundra
◦ Taiga or Coniferous Forest
◦ Deciduous Forest
◦ Grasslands
◦ Tropical Rain Forest
◦ Deserts
Biomes
◦ Aquatic Biomes
◦ Freshwater ecosystems
◦ Estuary= where fresh water and saltwater meet in a coastal area.
◦ Marine ecosystems= saltwater
◦ Intertidal zone= area of shore seen between low and high tides.
◦ Pelagic zone= largest ocean area.
◦ Benthic zone= ocean floor.
Relationships Among Organisms
◦ Symbiosis (Symbiotic Relationship)= a long-term association between
2 members of a community.
◦ 3 Types of Relationships:
◦ 1. Commensalism= 1 member benefits, the other is unaffected. Very
rare in nature.
◦ 2. Mutualism= both members benefit. Ex. Sea anemone & clown
fish.
◦ 3. Parasitism= 1 member benefits, the other is harmed. Ex. Flea on
dog.
Relationships Among Organisms
◦ Competition= when 2 or more organisms seek the
same resource that is in limited supply.
◦ * A resources may be food, water, mates, light, or
space.
◦ * Competition can occur between members of the
same species or different species.
Relationships Among Organisms
◦ Predation
◦ Predators= an organism that feeds on other living things
(prey).
◦ Prey= the organism being eaten.
◦ Important Note: Predators typically control the population
size of the prey species. Less predators= More prey.
Energy Flow Through Ecosystem
◦ Biomass= amount of biological matter in ecosystem.
◦ Energy Flow= the transfer of energy within an ecosystem
Food Chains & Food Webs
◦ Food Chain= shows the connections between organisms (Who eats what?)
◦ Food Web= shows the interactions between food chains.
◦ Decomposers= Live on dead or decaying organisms. (Ex. Fungi & Bacteria) AKA
Saprophytes
◦ Producers= plants and any other autotrophs (algae in oceans)
◦ Consumers= depend on other organisms for food. AKA Heterotrophs. (They must eat)
◦ Herbivores= Eat only plants.
◦ Carnivores= Eat only other animals.
◦ Omnivores= Eat both.
Ecological Pyramids
◦ Trophic Level= the positions occupied by an organism in a food chain.
Energy Pyramids
◦ 10% Law= the amount of energy available to organisms at a trophic
level is 10% of what was at the previous level.
Energy Pyramids
◦ Number Pyramid= the number of individuals in a population.
Energy Pyramids
◦ Biomass Pyramid= the amount of mass or living tissue at each trophic level.
Populations
◦ Population= a groups of organisms of the same species living in the
same area.
◦ Population dynamic= Study of the growth rate, density, and
distribution of a population.
◦ Growth Rate= the change in population size over a period of time.
◦ Immigration= organisms move INTO a population.
◦ Emigration= organisms move OUT of a population.
Populations
◦ Exponential Growth= occurs when population growth starts out slowly and then
increases rapidly as the number of reproducing individuals increase. AKA Jshaped curve.
Populations
◦ Logistic Growth= Shows when a population has reached its carrying capacity.
AKA S-shaped curve
◦ Carrying Capacity= The # of individuals the
environment can support in a given area.
Populations
◦ Limiting Factor= anything in a population that limits population
growth. Ex. Food, space, water, disease.
◦ Density-dependent factors= depends on # of individuals in
population. Ex. Competition, disease, predation.
◦ Density-independent factors= does NOT matter how many
individuals are in population. Ex. Natural disasters, weather, seasonal
cycles.
Succession
◦ Ecological Succession= the changes an ecosystem goes through over time.
◦ Primary Succession= occurs on rock (barren land). Ex. On newly formed
volcanic rock.
◦ Pioneer Species= The first species to grow on barren land.
◦ Secondary Succession= occurs where soil is already present. Ex. After
forest fire, other natural disaster, or logging.
◦ Climax Community= a mature relatively stable community where there is
little change in the predominant species in an area.
Primary Succession
Secondary Succession
Humans & the Environment
◦ Positive Human Actions
◦ Recycling
◦ Using renewable resources, instead on nonrenewable ones.
◦ Negative Human Actions
◦ Pollution= can occur in the air, soil, and water.
◦ Pesticides= chemical agents used to kill organisms, usually animals.
◦ Habitat Reduction= destroying habitats of organisms
◦ Urbanization= creating cities and suburbs, which disturbs the natural land.
◦ *Agriculture is the main cause of habitat destruction.
Biodiversity
◦ Biodiversity= measure of variety of organisms in an area.
◦ The more biodiversity, the better.
◦ Pollution, habitat destruction, etc. can lead to a loss of biodiversity.
◦ Biodiversity is often used to measure the overall health of an ecosystem.
Species Interaction
◦ Endangered or Threatened Species= means that very few of those organisms are
alive.
◦ These organisms may be put on Endangered Species List so that they are
protected.
◦ Non-native (Invasive) Species= foreign organism that enter ecosystems, usually
through human action. Ex. Kudzu, jumping carp.
Loss of Genetic Diversity
◦ Genetic diversity is a result of sexual reproduction.
◦ Loss of genetic diversity may result from cloning or asexual reproduction.
◦ This is a problem with monoculture farms that have large quantities of identical
organisms.
Global Warming
◦ Global Warming= describes the measured rise in the Earth’s atmospheric and
oceanic temperatures.
◦ Greenhouse Effect= traps solar heat within the Earth’s atmosphere.
Human Consumption
◦ Natural Resources= Ex. Water, soil, and air. What humans need for survival.
◦ Humans also use a great deal of power. (Fossil fuels, which are nonrenewable.)