Chapter 4Chapter 4Ecosystems and CommunitiesEcosystems and Communities

4-1 The Role of Climate4-1 The Role of ClimateA.A. What is Climate?What is Climate?

1. Climate is the average yearly condition 1. Climate is the average yearly condition of temperature and precipitation in a of temperature and precipitation in a region.region.

2. It's caused by latitude, winds, ocean 2. It's caused by latitude, winds, ocean currents, and the shape and height of currents, and the shape and height of land masses.land masses.

3. Climate affects ecosystems, because all 3. Climate affects ecosystems, because all organisms have certain needs for organisms have certain needs for temperaturetemperature

B.B. The Greenhouse EffectThe Greenhouse Effect

1.1. The greenhouse effect keeps the The greenhouse effect keeps the temperature on Earth within a temperature on Earth within a

good good range for life.range for life.

2.2. The gases in the atmosphere trapThe gases in the atmosphere trap heat-COheat-CO22, CH, CH44, water vapor, water vapor

3. 3. Heat energy cannot pass back out Heat energy cannot pass back out as easily as light energy as easily as light energy

entersenters

C.C. The Effect of Latitude on a ClimateThe Effect of Latitude on a Climate

1.1. Differences in latitude determine the Differences in latitude determine the amount of sunlight that hits and amount of sunlight that hits and then heats the Earth's surface.then heats the Earth's surface.

2.2. Differences in heating cause three Differences in heating cause three main climate zones:main climate zones:

a.a. Polar ZonePolar Zone - very cold areas - very cold areas

b.b. Temperate ZoneTemperate Zone - ranges from - ranges from hot to cold depending on hot to cold depending on the season.the season.

c.c. Tropical ZoneTropical Zone - always warm - always warm

D.D. Heat Transport in the BiosphereHeat Transport in the Biosphere

1.1. Unequal heating of Earth's surface Unequal heating of Earth's surface causes winds and ocean currents.causes winds and ocean currents.

2.2. Winds and currents move heat Winds and currents move heat through the biosphere.through the biosphere.

4-2 4-2 What Shapes an Ecosystem?What Shapes an Ecosystem?

A.A. Biotic and Abiotic FactorsBiotic and Abiotic Factors

1. Organisms are influenced by 1. Organisms are influenced by - biological (biotic) and- biological (biotic) and

- physical (abiotic) - physical (abiotic) factors.factors.

2. Biotic factors include all living 2. Biotic factors include all living thingsthings

3. Abiotic factors include climate, 3. Abiotic factors include climate, humidity, soil type, and humidity, soil type, and

other other nonliving factorsnonliving factors

B.B. The NicheThe Niche

1. 1. A niche includes what an organism A niche includes what an organism eats and how it gets its food, as well eats and how it gets its food, as well

as as the physical conditions, and when and the physical conditions, and when and how it reproduces.how it reproduces.

““the role an organism plays in its environment”the role an organism plays in its environment”

2. No 2 species can occupy the same 2. No 2 species can occupy the same niche.niche.

C. Community Interactions1. Communities interact in one of three

ways:a. Competition - organisms try to use the same resources they need to live. Competition often results in one organism dying out.b. Predation - this occurs when one organism (predator) captures and eats another (prey)

c.c. Symbiosis Symbiosis - occurs when two species live - occurs when two species live together in one of three ways:together in one of three ways:

i.i. Mutualism - both species Mutualism - both species benefit from benefit from the relationshipthe relationship

What are some examples?What are some examples?

ii.Commensalism - one species benefits ii.Commensalism - one species benefits and the other is neither and the other is neither helped nor harmed helped nor harmed

Examples?Examples?

iii.iii. Parasitism - one species Parasitism - one species benefits benefits by living in or on the other and the other is by living in or on the other and the other is harmed. Examples?harmed. Examples?

D.D. Ecological SuccessionEcological Succession

1. As an ecosystem ages, older inhabitants 1. As an ecosystem ages, older inhabitants die out and new organisms move in.die out and new organisms move in.

2. Ecological Succession is the predictable 2. Ecological Succession is the predictable changes that occur in a community.changes that occur in a community.

a. primary successiona. primary succession

b. secondary successionb. secondary succession

4-34-3 BiomesBiomes

A.A. Biomes and ClimateBiomes and Climate

1. A biome is a group of communities 1. A biome is a group of communities on land that covers a large area and is on land that covers a large area and is characterized by certain soil and climate.characterized by certain soil and climate.

B.B. The Major BiomesThe Major Biomes1.1. There are ten major biomes:There are ten major biomes:

- Tropical Rain Forest- Tropical Rain Forest - Tropical Dry Forest- Tropical Dry Forest - Tropical Savanna- Tropical Savanna - Desert- Desert - Temperate Grassland- Temperate Grassland - Temperate Woodland and Shrubland- Temperate Woodland and Shrubland - Temperate Forest- Temperate Forest - Northwestern Coniferous Forest- Northwestern Coniferous Forest - Boreal Forest (Taiga)- Boreal Forest (Taiga) - Tundra- Tundra

Tropical Rain ForestTropical Rain Forest

Tropical Dry ForestTropical Dry Forest Tropical SavannaTropical Savanna

Temperate GrasslandTemperate Grassland

Temperate Woodland and ShrublandTemperate Woodland and Shrubland

Temperate ForestTemperate Forest

Northwestern Coniferous ForestNorthwestern Coniferous Forest

Boreal Forest (Taiga)Boreal Forest (Taiga)

TundraTundra

Desert

4.4 Aquatic Ecosystems4.4 Aquatic Ecosystems

A. Freshwater EcosystemsA. Freshwater Ecosystems1. Flowing-Water—such as rivers,streams

creeks. The turbulent water has more dissolved O2 than still water.

2. Standing-Water—lakes, ponds. These contain phytoplankton (single-celled algae) and zooplankton.

3. Freshwater wetlands—water either covers soil or is at or near the surface of the soil for at least part of the year.

3 types of wetlands: 3 types of wetlands: – Bogs—dominated by sphagnum mossBogs—dominated by sphagnum moss

– Marshes—shallow wetlands along riversMarshes—shallow wetlands along rivers

– Swamps—usually have slowly flowing water, Swamps—usually have slowly flowing water, and have trees and shrubsand have trees and shrubs

B. Estuaries—where rivers meet the sea; serve as B. Estuaries—where rivers meet the sea; serve as spawning and nursery grounds for fish and spawning and nursery grounds for fish and shellfishshellfish

2 types: 2 types: salt marshessalt marshes—temperate zone —temperate zone estuaries; and estuaries; and mangrove swampsmangrove swamps—across —across tropical regions tropical regions

C. Marine EcosystemsC. Marine Ecosystems– Divided into areas according to amount of Divided into areas according to amount of

sunlight or depth and distance from shoresunlight or depth and distance from shore

– SunlightSunlight: : photic zonephotic zone—depth to which sunlight —depth to which sunlight penetrates; penetrates; aphotic zoneaphotic zone—sunlight does not —sunlight does not reach, so chemosynthetic autotrophs are found reach, so chemosynthetic autotrophs are found herehere

– Depth and distance from shore: Depth and distance from shore: intertidal zone, intertidal zone, coastal ocean, open ocean, coral reefs, and coastal ocean, open ocean, coral reefs, and benthic zonebenthic zone