Chapter 4Ecosystems & Communities

• What is the difference between weather and climate?

4.1Climate

The three main zones are the polar, tropical, and temperate climates.

polar climate: the far northern and southern regions of Earth

tropical zone: surrounds the equator

temperate zone: the wide area in betweenthe polar and tropical zones

The Greenhouse Effect

• Greenhouse gasses such as carbon dioxide trap heat in the Earth’s atmosphere.

Every Organism has a habitat and Niche

A habitat is the general place in which an organism lives.

A niche describes not only the place an organisms lives, but the range of physical and biological conditions in which it lives and interacts.

4.2 Niches and Community Interactions

The Competitive Exclusion Principal

• If two species attempt to occupy the same niche, one species will be better suited to obtain limited resources and will eventually exclude the other.

What would happen if two of these warbler species tried to occupy the same niche at the same time?

Community Interactions

Predator-Prey

Herbivore-Plant

Symbiotic Species

Two or more species living together in a close, long-term association.

Parasitism – the host is harmed and the parasite benefits

Ex: lice, hookworm, roundworms

Organism benefits

0

_

Organism is harmed

Hornworm caterpillarThe host

hornworm will eventually die

as its organs are consumed

by wasp larvae.

Braconid wasp

Braconid larvae feed

on their host and release themselves

shortly before

reachingthe pupae stage of

development.

_

Parasitism

+

0

Mutualism – benefits both participating species

Ex: Clownfish and sea anemone

Commensalism – one species benefits, and the other is neither harmed nor helped

Ex: Barnacles on a blue whale

4.3 Succession

When new land is created, or a habitat is destroyed by disaster a new habitat will be created.

Succession is a regular progression of species replacement.

Primary succession occurs where life has not existed before.

Ex: A new volcanic island

Secondary succession occurs where there has been previous growth.

Ex: A forest that has been burnedUntamed science

video

4.4 BiomesBiomes are described in terms of abiotic

and biotic factors.

Tropical rain forest biomes produce lush forests.

warm temperature

abundant precipitation all year Source: World Meteorological Organization

Grassland biomes are where the primary plant life is grass.

Temperate grasslands are dry and warm during the summer; most precipitation falls as snow.

Tropical grasslands (savanna) are warm through the year, with definite dry and rainy seasons.

Desert biomes are characterized by a very arid climate.

very low amount of precipitation

four types: hot, semi-arid, coastal, and cold

Temperate forest biomes include deciduous forests and rain forests.

Temperate deciduous forests have hot summers and cold winters.

Deciduous trees are the dominant plant species.

The taiga biome is located in cooler northern climates.

boreal forest

long winters and short summers

small amount of precipitation

The tundra biome is found in the far northern latitudes with long winters.

winter lasts 10 months

limited precipitation

permafrost

4.5 Aquatic Ecosystems

• Nearly ¾ of Earth’s surface is covered with water.

• Aquatic organisms are affected primarily by water depth, temperature, flow, and amount of dissolved nutrients.

• Freshwater ecosystems include moving and standing water (wetlands, lakes and ponds, and rivers and streams).

Estuaries are dynamic environments where rivers flow into the ocean.

Mixture of fresh water with salt water

Serve as spawning and nursery grounds for many fish and shellfish

Chesapeake Bay

Louisiana bayous

Florida Everglades

Estuaries are highly productive ecosystems.

Estuaries provide a protected refuge for many species.

Estuaries are primarily threatened by land development.

Marine EcosystemIntertidal Zone

Affected by tides

Costal OceanCoral reefs and kelp forests

Open Ocean90% of oceanPhotic and Aphotic zones