Download Ecology Unit 2 1. ECOLOGY (Section 4-1)

Ecology Unit 2
1. ECOLOGY (Section 4-1) -is the study of the interactions between organisms and the living and
nonliving components of their environment.
A. Exploding human population
Over 6 billion people
Causes overcrowding , lack of food and space for waste disposal.
B. The Sixth Mass Extinction
Habitat destruction, overhunting, introduced diseases and predators
20% of the species of birds have become extinct in the past 2000 yrs.
1/5 of the species in the world may disappear in the next century
C. The Thinning Ozone layer
Ozone layer protects living organisms from harmful UV rays
CFC’s and some other chemicals are destroying the layer
In 1985 a “hole” (not a hole, but a thin layer) was discovered
In 1992 CFC’s were banned.
D. Climate Change
Greenhouse effect- is the mechanism that insulates Earth from the deep freeze of
space.
When fossil fuels are burned (coal, oil, natural gas) they provide energy and excess
CO2 is released.
Heat is trapped by the excess gas in the atmosphere and causes Global Warming.
Global Warming causes changes in weather, melting of polar ice caps, and rising sea
levels
2. Species Interactions (Section 4-2)
Symbiosis-the relationship between different species living in close association with one
another.
Predator-captures, kills, and consumes prey.
Natural Selection favors adaptations that improve the efficiency of predators. Natural
Selection also favors ways for prey to avoid being captured.
Mimicry-a harmless species resembles a poisonous or distasteful species. (Ex. king snake
(not poisonous) looks like the coral snake (poisonous).
Herbivores-animals that eat plants (a form of predation). Plants have developed
adaptations (both physical and chemical) to defend themselves.
Parasitism-resembles predation, one individual is harmed while the other benefits. A
parasite feeds of a host.
Ectoparasites – live outside the host (ticks, leeches, mosquitoes)
Endoparasites- live inside the host (malaria, tapeworms, bacteria)
Competition- results from niche overlap-the use of the same resource by two or more
species.
Mutualism- cooperative relationship in which both species derive some benefit.
Pollination-bees, animals, and insects get food from flowers. The plant will be
better able to reproduce.
Commensalism-is an interaction in which one species
benefits and the other is not affected.
3. Succession (Section 4-3)-the gradual sequential regrowth of
species in an area.
Primary succession-the development of a community in an
area that has not supported life previously (bare rock, sand
dune)
Secondary succession- is the sequential replacement of species that follows a disruption of
an existing community. (forest fire, volcano eruption, or human activity.)
Pioneer species-tend to be small, fast-growing, and fast reproducing and often are the first
to occupy an area during succession.
Climax Community-a traditional description of succession that ends at a stable point
4. Terrestrial Ecosystems (Section 4-4)- Biomes- very large land ecosystems that contain a
number of smaller but related ecosystems within them.
Tundra- cold, largely treeless (located northern North America, Europe, and Asia)
Largest and northernmost biome
Permafrost- a layer of permenantly frozen soil under the surface.
Little precipitation, very short growing season (two months)
Plants= grass, sedges, moss
Animals- caribou, foxes, snowshoe hares
Taiga- located south of tundra (Think Northern New Hampshire, Maine)
Mostly forest (cone-bearing trees like pines, furs, hemlock)
Long winters
Animals= moose, bear, wolves, lynx.
Temperate Deciduous Forest- trees that lose all their leaves in the fall. (Massachusetts!)
Pronounced seasons, even precipitation all year.
Deciduous trees have broad, thin leaves to maximize light absorption.
Plants= birch, beech, maple, oak, hickory, sycamore, elm
Animals= deer, foxes, raccoons, squirrels
Temperate Grassland- dominated by grasses.
Usually in the interior of continents (think the Midwest of the U.S.-also called
prairie)
Have rich fertile soil- support farming
Grass supports many grazing animals
Deserts- receive less than 25cm of rain each year.
Hot days, cold nights
Many animals and plants have adapted to conserve water.
Savannas- tropical or subtropical grasslands with scattered trees and shrubs (Africa)
Alternating wet and dry seasons
Animals= wildebeest, giraffes, zebra, gazelles
Tropical Rain Forest- tall trees, found near equator
Stable year round growing season, abundant rainfall
Many plants compete for sunlight
Canopy- a continuous layer of trees at the top that shade the forest floor
Highest species richness of all the biomes- many different animals and plants
Good website on Land Biomes below:
http://www.physicalgeography.net/fundamentals/9k.html