Science 14 Unit D
Chapter 14 Notes
Chapter 14: Ecosystems and Biomes
Notes
Introduction
-over the last several hundred years, Alberta’s original ecosystems have changed – this caused changed
in the types of plants, soil and animals
14.1 Ecosystems
-the number and type of living things in an area depend on factors such as temperature, amount of
precipitation and type of soil (each factor is an example of the physical, non-living environment)
-both living organisms and non-living factors make up an ecosystem
-biotic community - living components of an ecosystem
-abiotic community – non-living components of an ecosystem
-these factors interact with each other and affect the local environment
-How Large are Ecosystems
-can be large or small – i.e. pond, forest, underside of a leaf
-must include the following interactions:
-living things interact with one another
-living things interact with other species
-living things interact with abiotic factors that make up their environment
Science 14 Unit D
Chapter 14 Notes
14.2 Climate and Land Ecosystems
-why do animals or plants only live in certain regions (i.e. why don’t cactuses grow in Northern Alberta?)
-Climate! – average weather conditions based on long term records
-each type of climate has a range of temperatures and a range of annual precipitation
-climate is important because it affects living things – i.e. regulates reproductive cycles, some
animals have their young in spring when there is more food
-topography –area’s physical features (i.e. rivers/lakes)
-aquatic plants and animals live in water – other animals like to live near water
-large bodies of water help to cool a hot climate and warm a cool one (recall sea and land
breezes)
-altitude – aka elevation – refers to height of area above sea level
-affects type of plants and animals found in an area – i.e. travelling up a mountain there is a
range of vegetation
-latitude –refers to how far north or south you are from the equator
-the amount of the Sun’s energy you receive changes with latitude – the equator is hotter
because it receives more direct solar radiation than the poles do
-in Alberta, the climate is colder in the north than in the south
-mountain ranges – influence climate
-i.e. Rocky Mountains – most air from the Pacific ocean rises up over the mountain and then
drops most of it’s moisture – grasslands east of the mountains get little rain
-north eastern Alberta is farther away from the mountains and gets enough precipitation for
large forests to grow
Science 14 Unit D
Chapter 14 Notes
14.3 Location and Soil
-type of soil in an area can be affected by latitude, altitude and topography – the type of soil affects the
number and types of plants – this then affects the number and types of animals
-soil – thing layer of rock fragments that cover the land – good soil contains plant nutrients such as
nitrogen
-smaller particles are called clay, next largest – silt, sand, gravel
Humus in Soil
-soil contains animal wastes and decaying organisms – decomposers in the soil consume this
matter and help it to decay and is dragged underground by earthworms – the material
eventually becomes humus
-consists of fibres, soil particles, black sticky liquid (decayed remains)
-because the humus is sticky it bind particles of various sizes to make soil crumbs – good for
many reasons
-spaces between crumbs allow plant roots to grow and spread out
-spaces between crumbs allow air into the soil
-help keep soil moist but allow excess water to drain away
-less likely to be blown away by wind than small soil particles
-humus also helps prevent minerals from being leached out (washing out of soil materials by
rain)
-eventually broken down completely leaving behind its valuable minerals in the soil
Science 14 Unit D
Chapter 14 Notes
14.4 Biomes
-recall: plants and animals in a region are determined by climate and soil
-some areas can be grouped if they have similar climate/soil – these are called biomes
-biome – large geographic area with distinct plants and animals
-In Alberta:
-boreal forest – more precipitation than grasslands – winters are long and cold – summers are
cool but days are long – mixed forests of aspen, spruce, pine – moose, mosquitoes, caribou
-moutain and foothill – extreme variations in temperature/precipitation due to altitude – higher
elevations are colder and have a short growing season – coniferous forests grow on sides of
mountatins – elk, moose, black bears
-parklands – more precipitation than grasslands - winter/summer are colder – deer, Baird’s
sparrows, red-tailed hawks – aspen trees and fescue grasses
-grasslands – have lowest precipitation in Alberta – summers are hot, winters are cold – mixed
grasses – burrowing owls, swift fox, pronghorns
-Northern Boreal – stretches across Canada, northern Europe and Asia – due to cold and wet, soil is
acidic so earthworms are rare which means that dead organisms and waste decompose slowly -although
cold, some days get pretty hot
-biodiversity/diversity – number and variety of living things in an area
-Grassland – extension of great western plains in the US – few trees because of low precipitation, drying
winds, extremely cold winters, fierce snowstorms in late spring, drought in summer
14.5 What Threatens Biodiversity?
-many plants and animals only have small areas to live in and over the last 100 years, several organisms
are extinct
-extinction – elimination of a species from Earth
-sometimes is it is a natural process but sometimes a species is unable to adapt to a climate
change (i.e. woolly mammoth during ice age)
-other natural disasters (i.e. volcanic eruption/flood) can also cause extinction
Science 14 Unit D
Chapter 14 Notes
-Human Impact on Biodiversity
-habitat – an organism’s shelter and food
-many animals become extinct because of loss of habitat – this is often the result of human activity (i.e.
filling in wetlands, logging, farmers, dams, etc…)
-species at risk – plants and animals that are close to becoming extinct