Ecology Review

ScienceBennett

• The area of our planet upon which life is possible is called the biosphere.

• This thin layer is affected by many factors.• Although the entire biosphere is considered

one biological system, it is easier to consider smaller units, called ecosystems.

Ecosystems

• An ecosystem is any stable environment where living and nonliving things interact, and in which materials are recycled.

• The size of the ecosystem is not particularly important.

• What matters is that the system works as a unit.

• Within each ecosystem, there exists a community of all the living organisms.

Communities

• Each community consists or many populations of organisms.

• A population is made up of only one kind • of organism (ex. mosquitoes).• An ecological niche is the way in which a

species uses the available resources to survive, and the way its existence affects the other organisms living around it.

• The ecosystem is influenced by many aspects of the physical or nonliving environment, such as:

• soil• temperature• water• energy• the atmosphere• biochemical cycles

Soil

• The upper layer of the soil is called the topsoil, and contains organic matter in the form of decayed remains of vegetation, along with a variety of soil-dwelling organisms.

• The maintenance of soil fertility, pH and composition is vital to the ecosystem.

pH

• The pH scale is a scale used to describe the acidity or alkalinity of soil or a solution.

• A pH value of 7 is considered to be neutral. Larger numbers are more basic (alkaline) and smaller numbers are more acidic.

Energy

• Photosynthesis is the process by which plants convert light energy into chemical energy.

• Plants convert water, carbon dioxide (the source of carbon), and sunlight into carbohydrates (sugars and starches) and oxygen.

So, light + water + carbon dioxide produces carbohydrate + oxygen

• Plants and animals use cellular respiration to turn the stored energy in carbohydrates (source of carbon) into chemical energy for cells.

So, carbohydrates (source of carbon) + oxygen produces carbon dioxide (holds the carbon) and water.

• Since the carbon is repeatedly cycled through both processes, this is called the carbon cycle.

• Other nutrients and elements cycle through the biosphere, such as the

- nitrogen cycle- phosphorus cycle- water cycle

How can soil composition and fertility be altered in an ecosystem?

• To be fertile, soil requires:– minerals– appropriate ph– proper amount of water– most plants thrive in pH 7

– Acid rain makes the soil more acidic and then plants grow poorly and the decomposers (bacteria and fungi) die.

Bioaccumulation or Bioamplification

• is the accumulation of a fat-soluble (dissolves in fat) pesticide or toxin in the body of organisms as it passes up the food chain

• The organism at the top of the food chain has the greatest concentration of the pesticide.

Biomes

• 1. Tundra – poor soil quality, low to no precipitation, called an arctic or cold desert

• 2. Boreal forest- coniferous (pine) trees, 40 cm/year precipitation

• 3. Temperate Deciduous Forest- deciduous trees, 100 cm/year precipitation, we live here!

• 4. Grassland- grasses, 25-75 cm/year precipitation, Manitoba to Rocky Mountains

Why might a species be classified as endangered?

• The species is close to extinction in all parts of Canada (or in a significantly large location).

• This is due to:– climate change– competition from other species– impact of human activities

Biodiversity

• Biodiversity is the variety of different species in the ecosystem.

Biodiversity is decreased by extinctions!