Introduction to Ecology Chapter 40

Ecology Study of the interactions between organisms and the environment. Can be studied at levels from a single organism up to entire biosphere. We’ll focus on population, community, and ecosystem ecology.

Distribution of species Where do organisms live and why? Biotic factors: behavior, interactions with other organisms (predation, food sources, alien or non-native species) Abiotic factors: temperature, water, sunlight, soil, nutrients

Climate …is the average long-term weather of an area; varies with differing amounts of solar energy received by different places on Earth. Solar energy input determines temperature, precipitation, and air and ocean circulation patterns which leads to different climates and vegetation patterns.

Uneven Heating Regions near equator are hot due to more direct sun rays, concentrating energy in a smaller area. Regions near poles are cold due to the acute angle of rays. Regions in between have intermediate temps.

Seasonal Changes The 23.5 degree axis tilt causes regions to receive more direct rays during certain times of the year. Our winter = northern hemisphere tilted away from sun. Our summer = northern hemisphere tilted toward sun.

Global air circulation Most precip tends to fall at equator (rainforests), tapering off towards 30 degrees latitude. Dry air descends at 30 degrees (deserts). Precip falls again at 60 degrees (decid. and conif. forests). Dry air descends at poles.

Microclimates …local climates that differ from the general climate of a region due to local topography. …formed by: Rain shadow effect: more arid conditions on leeward sides of mountain ranges. Cities: buildings block wind, absorb and emit heat. Land breezes/Sea breezes: day to night differences in coastal areas. Altitude: climate colder as elevation increases.

Rain Shadow Effect