1. Ecology Review Science Bennett

2. 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.

3. 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.

4. 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.

5. The ecosystem is influenced by many aspects of the physical or nonliving environment, such as: soil temperature water energy the atmosphere biochemical cycles

6. 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.

7. 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.

8. 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

9. 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.

10. 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

11. 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.

12. 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.

13. 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

14. 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

15. 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

16. Biodiversity Biodiversity is the variety of different species in the ecosystem. Biodiversity is decreased by extinctions!