Unit 3 - EcologySection 3 - Canada’s Biomes and Climate Change

Watch: “An Introduction to Biomes”

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Ecosystems can be grouped into larger categories called biomes. A biomeis a collection of ecosystems that are similar or related to each other,usually in the type of plants they support.

Biomes take into account not only biotic factors, but also abiotic factorssuch as average temperatures and the length of the seasons.

Canada can be organized into four major biomes.

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The Tundra Biome

Canada’s northernmost biome is called a tundra. What distinguishes thetundra from the other biomes is particularly the length of the growingseason, due to its cold temperatures.

Plants must fight to grow in permafrost, a layer of soil that never thaws.Plants usually extend their roots in the layer of soil that lies above thepermafrost, called the active layer. This layer thaws in the summer.Because of the permafrost, large trees cannot grow in the tundra.

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Summary of the Tundra:

Abiotic factors Communities- very low temperatures - rapid-flowering plants- short growing season - mosses and lichens- permafrost layer beneath soil - caribou and arctic wolves- low precipitation - wolverines and ptarmigans

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The Boreal Forest Biome

South of the tundra is the boreal forest biome. The boreal forest is foundin every province and makes up approximately 80% of the forested areas.

The boreal forest is dominated by conifers, which are trees withneedle-shaped leaves. These trees dominate the boreal forest because theyare very well adapted to extreme climates. The thin needle-like leaves losevery little water, making them suitable for the harsh winter and summers.

The forest floor is very shaded and only shade-loving plants can survive,such as moss and ferns. Also, only seed eating animals and variousherbivores can survive, such as squirrels and deer.

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Summary of the Boreal Forest:

Abiotic factors Communities- no permafrost - coniferous trees- changeable weather - seed-eating birds- soil contains some water - squirrels, voles, and hares- precipitation 40 cm/y or more - grey wolves

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The Temperate Deciduous Forest Biome

In Eastern and Central Canada is the temperate deciduous forest biome.This biome is dominated by deciduous trees such as maples and oaks. Thedeciduous trees have broad leaves that maximize light capture forphotosynthesis.

Temperate deciduous forests also experience higher temperatures whichresults in more vegetation and animal life. Many insects, amphibians,lizards, birds and large herbivores and carnivores make these forests theirhome.

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Summary of the Temperate Deciduous Forest:

Abiotic factors Communities- longer growing season than bo-real forest

- deciduous trees, many shrubs,and ferns

- higher temperature than borealforest and tundra

- many insects and mice

- fertile soil - squirrels and many birds- precipitation up to 100 cm/y - black bears, wolves, and deer

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The Grassland Biome

The grassland biome is found at approximately the same latitude asdeciduous forests. Grasslands receive less moisture than the deciduousforests. This results in too little water to support trees (except near pondsor lakes).

The black soil is considered to be the most fertile soil in the world.Grasslands are home to many animals such as snakes, grasshoppers,hawks, mice, and wolves. Grasslands once supported massive herds ofmigrating bison; however, this migrating pattern is slowly dissipating.

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Summary of Grasslands:

Abiotic factors Communities- longer growing season than bo-real forest

- fescue grasses

- higher temperature than borealforest and tundra

- grasshoppers, voles, and mice

- rich, fertile soil - snakes and hawks- precipitation from 25 - 75 cm/y - bison and wolves

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Assignment pg. 93

Questions: #’s 3, 5, 8

Watch: “Top 10 Amazing Places On Earth You Won’t Believe Are Real”

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Climate and Global Warming

What is climate?

Climate is the average weather conditions in a particular location or regionat a particular time of the year. Climate is usually measured over a periodof 30 years or more.

How does Earth regulate climate?

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The various gases in Earth’s atmosphere essentially control Earth’stemperature. Specifically, carbon dioxide and water vapour are the twomain gases that provide the Earth with insulation.

This insulation works similar to how a greenhouse will keep in moistureand heat. Therefore, we called these gases greenhouse gases.

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According to NASA scientists, the planet’s temperature ultimatelydepends on the atmospheric level of carbon dioxide.

Global warming is essentially an increase in temperature near the surfaceof the earth. While such warming has occurred various times throughoutEarth’s history, it appears to be occurring very quickly today. Suchwarming is currently attributed to the rising CO2 levels in the atmosphere.

According to NASA’s recent study (October 15, 2014) carbon dioxide isresponsible for 80% of the radiative forcing that sustains the Earth’sgreenhouse effect.

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The Effects of Global Warming

The most immediate effect of global warming is an increase in global sealevel. This is a worldwide concern for human beings. Rises in sea level willnot only affect populations that are situated below sea level (theNetherlands, much of California, New Orleans, etc.), but will also alter thenaturally occurring cycles (water, carbon, nitrogen, and phosphoruscycles). This alteration will have an unpredictable effect on global climate.

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Various Charts Concerning Global Warming:

Figure : Atmospheric CO2 concentration using ice core proxy data and directmeasurements. Source: NASA GISS

Watch: “Analyzing Ice Cores”

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Figure : Global mean land-ocean temperature change. Green bars indicateuncertainty estimates. Source: NASA GISS

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Figure : Calculations of global warming prepared in or before 2001 from a rangeof climate models. This assumes no action is taken to reduce emissions.

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The Big Question: Is the human species causing or contributing toglobal warming?

If yes, then how are we contributing to global warming?

If no, then what is causing this serious spike in atmospheric CO2

emissions?

Watch: “Earth’s Frozen Regions and Global Warming” orWatch: “Wall-E” (Disney...)

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