ECOLOGY UNIT- Chapters 2, 3, and 4
Use the following guidelines to help outline each section. Include diagrams where appropriate to help visually understand information.
2.1- Organisms and Their Relationships
Ecology-study of relationships between organisms and their environment
Biosphere- area of earth that supports life; extends several kilometers into atmosphere and several kilometers into ocean
Biotic vs. Abiotic Factors – biotic = living – plants, animals, fungi; abiotic = nonliving – rocks, soil, air, wind
Levels of Organization –
Organism---population----community-----ecosystem-----biome-----biosphere
Habitat vs. Niche – Habitat = area where an organism lives; Niche = the organism’s role in the ecosystem (lifestyle)
Community Interactions and relationships
Competition – when organisms “fight” for the same resource; plants compete for
light
Predation – one organism eating another organism; lions prey on antelope
Symbiotic Relationships – close relationships that develop when organisms live
together
Mutualism – both organisms benefit from relationship; bee and
Flower, lichen (algae and fungi)
Commensalism – one organism benefits and one is not affected;
Clownfish and sea anemone
Parasitism – one organism benefits and one is harmed; dogs and
Heartworms.
2.2 Flow of Energy in an Ecosystem
Autotrophs vs. Heterotrophs – autotroph = makes its own food; plants, algae,
Cyanobacteria
Heterotroph = has to eat other organisms; herbivores,
Carnivores, omnivores, detritivores
Types of heterotrophs
Herbivore- eats plants; cow, rabbit
Carnivore – eats animals; wolf, fox
Omnivore – eats plants and animals; bear, human
Detritivore – eat dead matter; worms, aquatic insects
Trophic Level: each step in a food chain
Food Chain vs. Food Web vs. Ecological Pyramid (use diagrams)
Food chain = one pathway of how energy flows through ecosystem.
Plant - grasshopper -> mouse - snake
Food web = shows many interconnected food chains in ecosystem
Ecological Pyramids: diagram showing relative amounts of different substances at different trophic levels
Examples: ___energy______, _biomass______and ___numbers______
Draw and label an energy pyramid:
2.3 Cycling of Matter
Water Cycle- includes evaporation, runoff, precipitation, transpiration and percolation; see diagram
Carbon and Oxygen Cycle – includes respiration, photosynthesis, combustion, decomposition, and diffusion; see diagram
Nitrogen Cycle – includes nitrogen fixation, eating organisms, decomposition, denitrification and absorbtion of N compounds by plants; see diagram
Phosphorus Cycle – don’t have to know.
3.1 Community Ecology
Communities and Limiting Factors-
Community = group of interacting populations that live in same area
Limiting factors = any biotic or abiotic factor that restricts the amount of organisms in an ecosystem; sunlight, water, food sources
Ecological succession: Primary vs. Secondary
Succession = change in an ecosystem when one community replaces another
Primary = establishment of a community in an area of exposed rock that
Does not have any topsoil. Lichens create soil by breaking down rock. Very slowprocess
Secondary succession= Change that occurs to an ecosystem when a
Community has been removed but the soil remains. Could be caused
By a fire, flood or windstorm. Pioneer species begin it.
3.2 Terrestrial Biomes(be sure to list abiotic factors as well as characteristics of these regions…don’t worry about avg. rainfall or exact temp. ranges)
Tundra- treeless, permafrost, little precipitation, cold, grasses, shrubs. South of polar ice cap; N. Canada, Russia
Boreal Forest- taiga, coniferous forest (trees with needles), cool, some precipitation,
TemperateForest – deciduous forest, warm, cold seasons, moderate rainfall, maples, oaks
Temperate Woodland and shrubland – chaparral, CA, Mediterranean, less rainfall than temperate forest; mostly shrubs
Temperate Grassland–prairies, fertile soil, mostly grasses, Midwest, hot summers, cold winters, bison, deer, rabbits
Desert – little precipitation, hot during day, cool at night, cacti, lizards, birds, tortoises
Tropical Savannah – grasslands with some trees, hot, moderate precipitation, lions, hyenas, zebras
Tropical Seasonal forest – drier than tropical rainforest, trees lose leaves in dry season, rainfall is seasonal, elephants, tigers, monkeys
TropicalRain forest –warm temperatures, large amount of rain, most diverse wildlife, chimps, elephants, bats
Mountains – as altitude increase, it gets colder, with less rainfall, leads to different communities at different levels
Polar Region–N and S poles, ice, cold all year, penguins, seals, whales
3.3 Aquatic Ecosystems
Fresh water (how is it divided?)
Rivers and streams
Water flows in one direction from headwater to mouth
Organisms must be able to withstand constant current – plants root themselves, animals attach themselves – mayfly larvae.
Lakes and ponds
Littoral zone- shallows, sunlight reaches bottom; many producers
Limnetic zone – open water – top layer, light, dominated by plankton – algae, many fish
Profundal zone – deepest area, colder, lower in oxygen, little light, few organisms
Wetlands – swamps, bogs, marshes; support aquatic plants, duckweed, cattails, mangroves, willows; high species diversity- birds, raccoons, reptiles
Estuaries – freshwater from a river merges with ocean salt water. Third most diverse ecosystem, algae, marsh grasses, worms, oysters, crabs, mangroves, fish use as nursery for their young, waterfowl nest here.
IntertidalZone- narrow area where ocean meets land; divided into different zones depending on amount of water each gets.
Open ocean
Photic zone – light penetrates; plankton, fish, turtles, jellyfish,
Aphotic zone – light does not penetrate; dark and cold,
Benthic zone – along the ocean floor, sand silt and dead organisms, fish, octopus, squids; not as much diversity
Abyssal zone – very cold, organisms eat food that drifts down to the bottom, hydrothermal vents support variety of life – bactera, clams, crabs, etc.
Coastal oceans and reefs -
Coral reefs – very diverse ecosystem, warm, shallow marine waters, dominant organism = coral (animal), symbiotic relationship with algae –
Causes all the colors of a coral reef. Very fragile, susceptible to human
Pollution.
4.1 Population Dynamics
Population Density and Dispersion
Density independent factors vs. Density dependent factors (examples of each too)
Population Growth rate-
Exponential Growth Model (sketch graph)
Logistic Growth Model (sketch graph)
Carrying Capacity
Reproductive Patterns
r-strategists
k-strategists
4.2 Human Population
Demography-
Trends in Human Population growth
Demographic transitions
Zero population growth
Age Structure (include sketches of age structure diagrams)
Human Carrying capacity