Change

• The way that a population responds to short term stress and long term change depends on the ability of the organisms to meet their biological needs

• NEEDS: climatic conditions (temperature, light, moisture), food, water, shelter, space, and opportunity for reproduction.

• Most organisms can survive with a loss of one or more of these factors for a short period of time, but will die if one or more of these biological needs is not met for a long period of time.

• Some may become extinct

• Short Term Stress:

• Examples of short term stress include seasonal peaks in temperature, sudden changes in water supply, or sudden but limited human impact.

• Long Term Change:

• Climate change (global warming), infestation by foreign plants and animals (exotic species), and permanent human influence (habitat destruction, acid deposition, etc.) are examples of long term change.

Read p. 14-19• Extinct: A species that has

disappeared everywhere• Endangered: close to

extinction in all parts of Canada or a large location.

• Threatened: any species that is likely to become endangered if factors that make it vulnerable are not reversed.

• Vulnerable: any species at risk because of low or declining numbers

• Extirpated: a species that no longer exists in one part of Canada, but found in others.

Biomes

• A biome is defined as a large geographical region that has a particular type of climax community.

• biome is therefore a distinct ecological community of plants and animals living together in a particular climate.– There are many different climates on the earth, and

different plants and animals have adapted to living in certain conditions. These conditions, such as the range of temperature and rainfall that occur on average in a particular place, are called the climate.

• The main factors that determine biome distribution include latitude, altitude, soil, temperature, precipitation, mountain chains, air and ocean current and light.

Factors affecting Biomes

• Temperature and rainfall– Terrestrial Biomes are influenced– Temperature influences the availability of water to

plants, soil and animals.• Hotter: water evaporates faster• Cold: temperature can lock water in ice.

• Latitude:– Distance north or south from the equator. (0 latitude)– It affects the angle at which the sun reaches the earths

surface. Due to the tilt on its axis.

Factors affecting Biomes

• Mountains– Elevation increases temperature decreases due

to thinning air retains less heat.

Factors affecting Biomes

• Air current– Warm air is less dense than cold air so it rises.– Warm air at the equator is transported.

Cool, moist air rises (rain)

Warm dry air falls

Hot moist air rises (rain)

Factors affecting Biomes

• Ocean currents– Warm water from the equator region is

transported north to warm the air in the northern hemisphere.

Major Biomes

• Terrestrial (land) biomes are defined by the dominant type of plant life (climax community). The terrestrial biomes include the:– Tropical Rain Forest,

– Temperate Deciduous Forest,

– Deserts,

– Grasslands,

– Taiga or Conifer (Boreal) Forest,

– and Tundra.

Note: Ecotone is the transition zone between two different plant communities, as that between forest and

prairie.

• Due to its latitude, Canada has four main terrestrial biomes which include the tundra, taiga, temperate deciduous forest, and grassland biomes.

Tundra• Makes up 1/5th of the earth’s total land• Permafrost which stunts growth.• Growth season of 2 months, harsh cold

winterVegetation: Tree-less, grasses, mosses, lichens.

Largest animals: Caribou, musk oxen, reindeer

Top predators: wolves, grizzly bear, white fox and snowy owl

Herbivores: grouse and lemmings

Summer sees migratory birds that feed on insects.

Conifer (boreal) Forest or Taiga•Long winters and short summers

•Short growing season

•Low diversity of life due to harsh climate

Vegetation: Evergreen trees, small compact wax coated leaves.

Animals; Elk, moose, deer, black bear, grizzly, porcupines, hares, lynxes, grouse, wolf, fox

Ground layer has less invertebrate and leaf litter is slower to decompose.

Temperate forest (Deciduous)

• Cool winters• Growing season of at least 4 months• Covers most of north America.

Vegetation: 4 layers of plant growth, tree, shrubs, field layer and ground layer.Birch, maple, oak, hickory

Animals: Chipmunks, squirrels, raccoons, mice,deer, wolves,foxes, etc.

Rich soil to support a large population of decomposers.

Temperate Rain Forest

• Plenty of rain fall• Growing season of at least 5

months

Vegetation: 4 layers of plant growth, tree layer, shrub, field and ground layerscedar and spruce, redwood

Animals: Chipmunk, squirrels, raccoons, elk, wolves, foxes, and other mammals

Topsoil supports a population of decomposers.

Grasslands

• Continental interiors.

• Transition zone between forest and desert.

• Hot-cold seasons, periodic drought and fires.

Vegetation: grasses and mixed legumes

Animals: rodents, large herbivore: bison, gazelles, zebra, horses.

Large predators like lions, wolves

Aquatic Biomes

There are also two types of aquatic biomes:– the marine (saltwater or ocean) biome, – and the freshwater biomes (rivers, lakes, ponds,

swamps, bogs, etc.).

Ocean• Covers 71% of earths surface

• But oceans are only about 1/3 as productive as land

• Life in the ocean is divided into two main groups:

• Benthic and Pelagic

Ocean

• Most important factors of a marine ecosystem are sunlight and nutrients.

• Light can only go about 200m below water.• Most of the nutrients are concentrated near

the bottom• Along the continental shelf there is more

life than in open ocean because nutrients are washed out from the land.

• Ocean food chain starts with free floating phytoplankton.– Algae, protist, shrimp and other crustaceans.

• Next in the food chain is Zooplankton.

Estuaries• Area in which fresh water meets saltwater.

• Coastal wetlands are rich in nutrients, water is shallow and plants can attach to the bottom.

• Breeding grounds for a range of organisms, including most commercially important fish.

Freshwater Biomes

– Lakes and ponds are like ocean, in that they are divided into separate zones which are defined by their distance from the shore.

– Rivers and streams mostly get started from mountainous ice and snow melting and springs. Rivers and streams end up at the ocean or another waterway.