COMMUNITIES, BIOMES, AND ECOSYSTEMS

SECTION 3.1 - NOTESCOMMUNITY ECOLOGY◦Main Idea: All living organisms are limited by factors in the environment.

QUESTIONS:◦What are some changes you associate with the change of seasons?

◦Why do these changes occur?

COMMUNITIES◦Biological Community - groups of different populations that live in the same area at the same time.

◦Organisms adapt to the conditions where they live. EX: animals with fur coats to keep them warm.

QUESTION: Think of some adaptations for organisms that you know about other than the ones we have already talked about.

LIMITING FACTORS◦Limiting factor would be any abiotic or biotic

factor that limits the growth, reproduction, or distribution of organisms.

◦Abiotic factors could include: Sunlight, climate, temperature, water,

nutrients, fire, soil chemistry, space ◦Biotic factors could include: Living things

If one species is restricted in growth, can allow another species to increase EX: tall trees knocked down, lets grass

and bushes increase

RANGE OF TOLERANCERange of tolerance - any environment factor that has an upper and lower limit that defines the conditions that the organism can survive in.

Tolerance is the ability of any organism to survive when subjected to abiotic or biotic factors.

Figure 2, pg. 61QUESTION: Why do humans have a wider range of tolerance than most other organisms?

ECOLOGICAL SUCCESSIONEcosystems are constantly changing.◦EX: tree falls down, forest burns down

QUESTION: Name some areas that might be more susceptible to disturbances.

Ecological succession is the change in an ecosystem that happens when one community replaces another as a result of changing abiotic and biotic factors.◦Lichen to small annual plants, perennial herbs and grasses, shade intolerant trees, to large trees

2 types of ecological succession:◦Primary succession◦Secondary succession

PRIMARY SUCCESSION Primary succession occurs on a solidified lava

flow or exposed rocks, cliff, where NO soil is present.

Primary succession occurs only once. Pioneer species are the 1st

organisms to appear. They are the species that start the process of soil formation for succession to take place. Common pioneer species to begin breaking

down rock are lichen. Order of succession: Rocks to lichens to small annual plants to

perennial herbs and grasses, to shade intolerant trees

PRIMARY SUCCESSION – CONTINUED

Climax community is when a stable, mature community is developed with little change in species◦Not likely to occur due to disturbances and or climate changes

SECONDARY SUCCESSION Secondary succession can take place after

disturbances like: fire, flood, or storm that have disrupted the communities that live there.◦Possible that new species of plants and/or

animals might occupy that habitat. Definition for secondary succession is the

orderly and predictable change that gradually takes place after a community of organisms has been removed but the soil has remained intact.◦Secondary succession will begin with a

pioneer species.◦Secondary succession will occur faster than

primary succession, because soil already exists.

SECONDARY SUCCESSION – CONTINUED Natural communities always changing. Human activities also affect the species present.

So difficult to determine if succession reaches a climax community in many areas on Earth.

SECTION 3.2 – TERRESTRIAL BIOMES MAIN IDEA – Ecosystems on land are grouped into biomes primarily based on the plant communities within them.◦Plant communities are specific to particular ecosystems.

QUESTION: Why do you think the plants might be different in each major area?

QUESTION: Why might the species in one biome be more diverse than the species in another?

EFFECTS OF LATITUDE AND CLIMATE

Everyone is affected by weather and climate.

Weather – is the condition of the atmosphere at a specific place and time.

LATITUDE Latitude is the distance at any point on the surface of Earth north or south from the equator.◦0° = equator◦90° = N or S pole◦Sunlight strikes Earth most directly at the equator = warmer temperatures

◦Sunlight strikes Earth indirectly at poles = cool/cold temperatures.

◦Creates 3 zones Polar, temperate, and tropical

CLIMATE Climate is the average of all weather conditions

in the area, includes temperature, precipitation, humidity, etc.

The single feature that is primarily responsible for the variation of climate in different parts of the is the angle of incoming sunlight.◦Other things that affect climate: Elevation Continental landmasses Ocean currents

In a biome the plants and animals have adapted to the region’s climate.

QUESTION: What are some things that humans are doing to affect climates around the globe?

MAJOR LAND BIOMES Biomes are classified primarily according to the

characteristics of their plants, animals, temperature and precipitation.

Different types of biomes:◦Tundra◦Boreal forest◦Temperate forest◦Temperate woodland and shrubland◦Temperate grassland◦Desert◦Tropical savanna◦Tropical seasonal forest◦Tropical rain forest

TUNDRA Tundra below the polar ice caps

◦Extends across N. Europe, N. America, and Siberia in Asia

◦Treeless biome with a layer of permanently frozen soil below the surface called permafrost. Trees cannot get their roots through the

permafrost. BOREAL FOREST

◦South of the tundra with dense evergreen forest extending across N. America, Europe, and Asia EX: spruce, fir, and pine trees

◦Could be called the taiga◦Lack a permafrost layer

TEMPERATE FOREST◦Cover much of S. Eastern Canada, eastern US,

most of Europe, parts of Asia and Australia◦Composed mostly of broad-leaved, deciduous

trees (shed leaves in autumn) EX: oak, maple, hickory and beech trees

◦All 4 seasons occur here TEMPERATE WOODLAND AND SHRUBLAND

◦Have less annual rainfall than temperate forests. Around the Mediterranean Sea, western

coasts of N. & S. America, S. Africa and Australia

◦Dominated by shrubs, called chaparral

TEMPERATE GRASSLAND◦Located in middle latitudes of N. & S. America, Asia, Africa, and Australia. Referred to as steppes in Asia, prairies in N. America, savannas in Africa, and rangelands in Australia

◦Have rich, fertile soils to support thick grasses or ideal for growing crops Also called grasslands

◦Drought, grazing animals, and fires keep grasslands from becoming forests. Most grasslands have been cleared for agriculture.

DESERT◦Deserts are areas where annual rate of

evaporation exceeds the rate of precipitation. Deserts on all continents except Europe

TROPICAL SAVANNA◦Located in Africa, S. America, and Australia◦Have grasses and scattered trees and receive

less precipitation than some tropical areas TROPICAL SEASONAL FOREST

◦Located in Africa, Asia, Australia, and S. & Central America

◦Resembles the temperate deciduous forest because in the dry season the trees loose their leaves to conserve water.

TROPICAL RAIN FORESTLocated in Central and S. America, S. Asia, W. Central Africa, and N. Eastern Australia

Has warm temperatures & large amounts of rainfall

Has the greatest biodiversity of all biomes

OTHER TERRESTRIAL AREAS Exceptions:

◦Mountains not characterized as biomes because their climate, plants, and animals changes with elevation

◦Polar regions are not true biomes because they are ice masses and not true land area with soil. Antarctica has recorded the coldest temperature on record at -89°C

Many species live in both polar regions

SECTION 3.3-AQUATIC ECOSYSTEMS MAIN IDEA

◦Aquatic ecosystems are grouped based on abiotic factors such as water flow, depth, distance from shore, salinity, and latitude

QUESTION:◦How do you and this community interact with local aquatic ecosystems?

FRESHWATER ECOCYSTEMS Freshwater ecosystems include:

◦Ponds, lakes, streams, rivers, and wetlands

◦Plants and animals have adaptation to live in fresh water and cannot survive in salt water

About 2.5% is fresh water◦68.9% in glaciers◦30.8% in groundwater◦.3% in lakes, ponds, rivers, streams and wetlands

RIVERS AND STREAMS Water flows in one direction

◦ Starts at the headwater◦ Travels to the mouth where it goes into a larger body

of water◦ Water can start from underground springs or from

snow melt◦ Water carries sediments as it moves

Sediment is material that is deposited by water, wind or glaciers

Speed of water movement depends on the slope of the ground Fast moving water usually have fewer species

living there Slower moving water allows plants to take root

and species to live there

LAKES AND PONDS Inland bodies of standing water are called lakes or ponds.◦Water temperatures varies by season◦Nutrient rich lakes are usually at lower altitudes and contain a lot of plant life and many different types of consumers.

TRANSITIONAL AQUATIC ECOSYSTEMS◦Areas where land and water interact or salt and fresh water intermingle EX: wetlands and estuaries

WETLANDS◦ Areas of land such as marshes, swamps, and bogs

that are saturated with water and support aquatic plants

◦ Plant species include: EX: pond lilies, cattails, mangroves

◦ Bogs are wet and spongy areas of decomposing vegetation that support many species of organisms.

ESTUARIES◦ Estuaries are an ecosystem that is formed where

freshwater from a river or stream merges with salt water from the ocean.

◦ Some species use estuaries as nurseries for their young, nesting, or migration rest areas

MARINE ECOSYSTEMS◦ Through photosynthesis marine (ocean) algae using

carbon dioxide from atmosphere will produce over 50% of the atmosphere’s oxygen.

Ocean is divided into different regions:◦ Intertidal zone a narrow band where the ocean meets

land Organisms have adapted to the tides, waves, and

periods of being wet and dry.◦ Open ocean ecosystems, which includes:

Photic zone, also called the euphotic zone, is shallow enough that sunlight is able to penetrate to a depth of 200m.

Aphotic zone is an area where sunlight is unable to penetrate and deeper than 200 m.

Benthic zone is the floor of the ocean