Chapter 3 Communities Biomes and Ecosystems 3 1

Chapter 3: Communities, Biomes, and Ecosystems 3. 1 – Community Ecology

Essential Questions – 3. 1 l How do unfavorable abiotic and biotic factors affect species? l How do ranges of tolerance affect the distribution of organisms? l What are the stages of primary and secondary succession?

Community Ecology l All living organisms are limited by factors in the environment. l Remember, a community is a group of interacting populations (all living organisms) in the same habitat. l Limiting Factor – any abiotic or biotic factor that restricts numbers, reproduction, or distribution of organisms.

Limiting Factors l Abiotic factors - Sunlight, climate, temperature, water, nutrients, fire, soil chemistry, and space. l Biotic factors – other living thing, such as another plant and animal. l Range of tolerance – the upper and lower limit of the factors in which an organism can survive.

Range of Tolerance Steelhead trout can live in water from 9 °C to 25 °C

Succession l If you didn’t cut your lawn, what would it look like in a year? 10 years? 50 years? l Grass gets taller, weeds grow and a meadow forms. l Bushes grow, trees appear and different animals move in. l Trees and bushes block light, grasses disappear. l 30 years later, the area is a forest.

Succession

Succession Ecological Succession = the orderly, natural changes and species replacements that take place in a community. It can take decades or centuries. l Primary Succession = the colonization of barren land (no soil) by organisms (Ex: after volcano dies) l Pioneer species are the first ones to take hold in the new area. Usually lichens and mosses.

Succession l Secondary Succession = is the sequence of changes that takes place after an existing community is disrupted some way. Ex: tornado, fire, etc. Soil already exists so secondary succession can take less time than primary. l Climax Community = A stable, mature community that undergoes little or no change. It may last for hundreds of years.

Chapter 3: Communities, Biomes, and Ecosystems 3. 2 – Terrestrial Biomes

Chapter 3. 2 – Essential Questions l How is latitude related to the three major climate zones? l What are the major abiotic factors that determine the location of a terrestrial biome? l How are the terrestrial biomes distinguished based on climate and biotic factors?

Latitude and Climate l Weather is the condition of the atmosphere at a specific place and time. l What causes weather? 1) The uneven heating of the sun. 2) Latitude and climate.

Latitude and Climate l Latitude is the distance of any point on the surface of Earth north or south of the equator. l Latitude is measured in degrees. The equator is 0° and the north/south poles are 90°

Latitude and Climate l Climate - The average weather conditions in area. It includes temperature and precipitation. l Biome - a large group of ecosystems that share the same climate and have similar types of communities. l Climate and latitude determine what a biome is like…

How Climate Affects a Biome