Chapter 4Ecosystems and Communities

Ch 4.1

Objectives• Differentiate between weather and climate• Identify the factors that influence climate

Weather vs. Climate• Weather is the day to day conditions of Earth’s atmosphere• Climate refers to average conditions over long periods

• Defined by year after year patterns of temperature and precipitation

Microclimates• Areas within a region can vary in their climate

• Ex: southern exposure, changes in elevation, land bordering large bodies of water

Factors that Affect Climate• Solar energy trapped in the biosphere• Latitude• Transport of heat by winds and ocean currents

Temperature• Earth’s average temperature is

determined by the balance of heat that stays in the biosphere and that which is reflected back to space• Greenhouse gases, like CO2,

cause more heat to be trapped near Earth’s surface

The Greenhouse Effect

Latitude and Solar EnergyThe angle at which the sun’s rays reach the Earth creates 3 distinct regions of climate: tropical, temperate and polar• Seasons are created by the tilt

of the Earth

Effect of Climate on Biomes

Ch 4.2 Niches and Community Interactions• Define niche• Describe the role competition plays in shaping communities• Describe the role predation and herbivory play in shaping

communities• Identify the three types of symbiotic relationships in nature

Niche• Organisms occupy different environments because each has a range

of conditions under which it can grow and reproduce• Every organism has a unique range of tolerance

• Tolerance for environmental conditions helps determine an organism’s habitat- general place where an organism lives

stress stress

Niche• An organism’s niche describes not only what it

does, but how it interacts with the biotic and abiotic parts of its environment• This includes:

• Place in food web• Environmental conditions it needs to survive• Type of food it eats• How it obtains food• Other species that use it as food• When and how it reproduces

What is the niche of a bullfrog?

Niche• Competitive Exclusion Principle - no two species can occupy the same

niche in the same habitat at the same time• Sharing a niche results in competition in nature often results in winner

and loser – losing organism fails to survive• Different species can occupy similar niches.

• Resource partitioning helps organisms with similar niches avoid competition

Warbler Niches

Bay-Breasted WarblerFeeds in the middlepart of the tree

Cape May WarblerFeeds at the tips of branchesnear the top of the tree

Spruce treeYellow-Rumped WarblerFeeds at the lower parts of the tree and bases of middle branches

Community Interactions

• Competition- same or different species attempt to use an ecological resource in the same place at the same time

Community Interactions

•Predation - one organism captures and feeds on another organism• Predator – the one killing and eating• Prey – the food

Community Interactions-Symbiosis• Symbiosis- an interaction between two species living close together• Three types:

• Parasitism – one is harmed (host), one benefits (parasite)• Mutualism – both benefit• Commensalism – one is neutral, one benefits

Mutualism

Parasitism

Commensalism