Chapter 4Chapter 4

Ecosystems & CommunitiesEcosystems & Communities

4-1 Role of Climate4-1 Role of Climate

I. What is Climate?A. Weather – day to day condition of Earth’s

atmosphere at a particular time & Places

B. Climate – average, year after year conditions of temperature & precipitation in a particular region

1. Caused by : a. Atmospheric heat trapping

b. Latitude

c. Wind & ocean currents

d. Amt. of precipitation

2. Contributors:a. Land mass shape

b. Land mass elevation

3. Determined by solar energy’s effect on temperature of atmosphere

II. II. Greenhouse effect Greenhouse effect – heat kept on Earth by – heat kept on Earth by atmospheric gasesatmospheric gases

A. Biosphere has a natural insulating blanket = atmosphereB. Functions of atmospheric gases:

1. Trap heat energy2. Maintain Earth’s temperature range

C. Gases include1. Carbon dioxide2. Methane3. Water vapor

D. Process1. Sunlight hits planet surface2. Is converted into heat energy3. Some is radiated back to air4. Some is trapped

E. Result → If there was no greenhouse effect, Earth would be 30°C cooler

III. Effect of Latitude on ClimateIII. Effect of Latitude on ClimateA. Tilt = radiation strikes at varying angles at different

times of yearB. Latitude = distance N or S from the equator

Differences in latitude create 3 main climate zones:

1. Polar – cold areas rays strike at very low angles2. Temperate – climate ranges from hot to cold

a. Most affected by changing anglesb. Has seasons

3. Tropical – located near equatora. Sunlight is direct or nearly direct year roundb. Always warm

IV. Heat transfer in biosphereIV. Heat transfer in biosphere

A. Unequal heating drives wind & ocean currentsB. Winds form because:

1. Warm air rises2. Cool air sinks

C. Movement creates air currents = winds → move heatD. Landmasses interfere w/ movement of air masses

4-2 What Shapes an ecosystem?4-2 What Shapes an ecosystem?

A. Biotic and Abiotic factorsA. Biotic – living influences on organisms

ex: plants, other animals, fungi, bacteria

B. Abiotic – physical or nonliving factors in an ecosystem

ex: temperature, precipitation, humidity, sunlight, wind, nutrient availability, soil type

C. Biotic & abiotic factors determine:a. Survival of organism

b. Growth of organism

c. Productivity of the ecosystem

D. Habitat – area where organism lives

II. The II. The NicheNiche -full range of physical & biological conditions -full range of physical & biological conditions in which an organism lives & the way the organism uses in which an organism lives & the way the organism uses those conditionsthose conditions

A. Part of the niche include:1. Place in food web2. Range of temperatures for survival3. Type of food it eats4. How it obtains that food5. What eats it6. Physical conditions

a. Where it livesb. Climate

7. When & how it reproduces

B. Combinations of biotic & abiotic factors in an ecosystem determine the number of different niches in that ecosystem

C. No 2 species can share the same niche in the same habitat at the same time (competitive exclusion principle)

III. Community InteractionsIII. Community Interactions → → powerfullypowerfully affect an ecosystem affect an ecosystem

A. Competition – organisms attempt to use resource in the same place at the same time

1. Resource – any necessity of life ex: water, nutrient, light, food,

space2. Two types

a. Direct – one winner; one loserb. Indirect – using up a resource before

another can use itB. Predation – one organism captures & feeds on

another organism1. Predator – kills & eats2. Prey - food

C. Symbiosis – any relationship in which two species live closely together

1. Mutualism – both benefita. Flowers need insects for pollinationb. Insects get food from flowers

2. Commensalism – one benefits; other not affecteda. Barnacles attach to whales → constant source of

food from H2Ob. Whales are not helped or harmed

3. Parasitism – one benefits; one harmeda. Parasite lives on or in another organism → getting

nutritionb. Host – organism that is fed on

a. Usually larger than the parasiteb. Is not killed but weakened

c. Ex: ticks, lice

IV. IV. Ecological SuccessionEcological Succession-- series of predictable series of predictable changes that occur in a community over timechanges that occur in a community over time

A. Results from:1. Slow changes in physical environment

2. Sudden natural disturbance

B. Two Types:1. Primary – occurs where no soil exists

2. Secondary – disturbance to existing ecosystems

4-3 Biomes4-3 BiomesBiome – a complex of terrestrial

communities that cover a large area and is characterized by certain soil & climate

Tolerance – ability to survive & reproduce under not the best conditions

Too much or too little of any environmental factor can make it difficult for an organism to survive.

I. Biomes & ClimateI. Biomes & Climate

Each species is adapted to certain conditions

Climate determines which organisms survive

2 most important elements of climate:

a. Temperature

b. Moisture (precipitation)

II. Major BiomesII. Major BiomesA. Each biome is defined by unique set of abiotic

factors & characteristic groups of plants& animals

B. Can have ecological variation within a biome due to :

1. Microclimate – climate in small area differs from surrounding climate

2. Geology – soil conditions or rock outcropping

C. Boundaries are not sharp. There are transition areas where animals & plants are shared

D. Ten different biomesD. Ten different biomes1. Tropical Rainforest

a. Has most speciesb. Forest parts

a. Canopy – top of treesb. Under story- between the canopy & the shrubsc. Shrubs – short bushesd. Herbs – ferns, grassese. Forest floor – leaves, moss, fungi

c. Abiotic Factorsa. Climate – hot year round, lots of precipitationb. Soil – thin & nutrient poor

2. Tropical Dry Foresta. Rainfall – highly seasonalb. Deciduous Trees – shed leaves during a particular seasonc. Abiotic Factors

a. Climate – warm year roundb. Soil – Rich

3. Tropical Savanna

a. Also known as grasslandsb. Have isolated treesc. Abiotic factors:

a. Climate – warmb. Soil – compactc. Frequent fires

4. Deserta. All are dry. Have <25 cm of annual precipitationb. Vary in conditions because of elevation and latitudec. Abiotic factors:

a. Climate – extreme temperature changesb. Soil – rich in nutrients & poor in organic matter

5. Temperate Grasslanda. Also known as plains & prairiesb. Occasional firesc. Abiotic factors

a. Climate – seasonsb. Soil - fertile

6. Temperate Woodland & Shrub land

a. Also known as chaparral = mix of shrubs & open woodlands

b. Periodic fires

c. Abiotic factors:

a. Climate – hot dry summer, cool moist winters

b. Soil – Thin nutrient poor

7. Temperate Foresta. Mix of deciduous & coniferous trees

b. Coniferous trees produce seed bearing cones

c. Abiotic factors:

a. Climate – warm summers, cold to moderate winter

b. Soil – rich in humus – decaying organic matter

8. Northwestern Coniferous Foresta. Also called temperate rain forest – lush vegetation

b. Moss covers tree trunks & forest floor

c. Abiotic factors:a. Climate – mild

b. Soil – rocky, acidic

c. Precipitation = abundant

9. Boreal Foresta. Also called taiga

b. Dense evergreen (coniferous) forest

c. Abiotic factors:a. Climate – bitter cold winter, short mild summer

b. Soil – acidic, nutrient poor

c. Precipitation - moderate

10.Tundraa. Permafrost – layer of permanently frozen

subsoil

b. Plants are small & stunted

c. Abiotic factors:a. Climate – short soggy summer; long, cold, dark

winter; Cold temp; high winds

b. Soil – humus poor

III. Other Land AreasIII. Other Land AreasA. Mountain Ranges

1. Found on all continents

2. Biotic & abiotic conditions vary with elevation

3. Elevation increases, temperatures & precipitation

B. Polar Ice Caps1. Border the tundra

2. Cold year round

3. Plants & algae include moss & lichens

4. Dominant animals

a. North polar region = polar bears, seals, insects

b. Antarctica = penguins, marine mammals

4-4 Aquatic Ecosystems4-4 Aquatic Ecosystems

¾ ‘s of Earth’s surface is covered by water

Aquatic ecosystems are determined by:

a. Depth

b. Flow

c. Temperature

d. Chemistry

OverlyingWater

Biomes are grouped geographically

Aquatic groups are grouped by abiotic factors

1. Depth – determines amount of light organisms receive

2. Chemistry – amount of dissolved salts, nutrients and O2

3. Latitude

I. Freshwater EcosystemsI. Freshwater EcosystemsA. 3% of surface waterB. Two types

1. Flowing – Water Ecosystemsa. Includes rivers, streams, creeks & brooksb. Organisms adapt to rate of flow

Insect larvae have hooks to hold onto plants Catfish have suckers to attach to rocks Trout have streamlined bodies that help them move with or

against current

2. Standing Water Ecosystemsa. Include lakes & pondsb. Water flows in & and out and circulates within them

c. Circulation distributes heat, nutrients and O2

d. Plankton lives here Phytoplankton – free floating unicellular algae Zooplankton – animal plankton that feed on algae

Which is Phytoplankton and Zooplankton?Which is Phytoplankton and Zooplankton?

Zooplankton Phytoplankton

C. Freshwater C. Freshwater WetlandWetland– – water coverswater covers the soil the soil or is present at or near the surface of soil for at or is present at or near the surface of soil for at least part of yearleast part of year

1. May be flowing or standing

2. May be fresh, salty or brackish – mixture of fresh & salty water

3. Very productive

4. 3 typesa. Bogs – dominated by moss; water is acidic

b. Marsh – shallow wetlands

c. Swamp – flooded forests

II. II. EstuariesEstuaries – wetlands formed where rivers – wetlands formed where rivers meet the seameet the sea

A. Contain mixture of fresh & salt waterB. Affected by rise & fall of oceanC. Many are shallow – so sunlight can

power photosynthesisD. Primary producers include:

1. Plants 2. Algae3. Photosynthetic bacteria4. Chemosynthetic bacteria

E. Much organic matter enters the web as

detritus – decaying organic matterF. Area serves for:

1. spawning – reproduction2. nursery – feed & growth

G. Types of Estuaries1. Salt marsh

a. Found in temperate zonesb. Dominant plants – salt tolerant grasses

2. Mangrove swamp – coastal wetlandsa. Widespread across tropical regionsb. Dominant plants – salt tolerant trees

III. Marine EcosystemsIII. Marine Ecosystems

A. Photosynthesis limited to photic zone – well lit upper layer

1. Only goes to a depth of 200m

2. Only place where algae & producers can live

B. Aphotic zone – permanently dark zone• Only producers that survive here are

chemosynthetic

C. Zones below are based on depth & distanceC. Zones below are based on depth & distance1. Intertidal Zone

A. Closest to shoreB. Organisms are exposed to regular & extreme changes in:

• Air• Water• Sunlight• Temperature• Waves & strong currents

C. Many types of communitiesD. Competition leads to zonation – prominent horizontal banding of

organisms2. Coastal Ocean

a. Extends from low tide mark to outer edge of continental shelfb. Border that surrounds the continentsc. Shallow mostly in photicd. Rich in plankton e. Most productive community is kelp forest

3. Coral Reefs

1. Most diverse & productive2. Named for coral animals – have hard calcium skeletons3. Coral live symbiotically w/ algae

• Algae carry out photosynthesis using coral waste • Algae provide coral w/ essential carbon compounds

4. Open Oceana. Also called oceanic zoneb. Largest marine zonec. Ranges in depth from 500 m to 11,000 md. Organisms are exposed to :

• High pressure• Frigid temperature• Total darkness

e. Low level of nutrients

5. Benthic Zone – covers the ocean floora. Organisms live attached or near the bottom

• Sea stars, anemones

b. Depend on food from organisms that grow in the photic zone

c. Deep sea vents have chemosynthetic producers