Communities and Biomes Biology I

Community Ecology: Lesson Objectives Recognize how unfavorable abiotic and biotic factors affect a species. Describe how ranges of intolerance affect the distribution of organisms. Sequences the stages of primary and secondary succession.

Main Ideas All living organisms are limited by factors in the environment. Ecosystems on land are grouped into biomes primarily based on the plant communities within them. Aquatic ecosystems are grouped based on abiotic factors such as water flow, depth, distance from shore, salinity, and latitude.

Communities A group of interacting populations that occupy the same area at the same time. Not every community contains the same variety Ex. Urban vs. rural, desert vs. artic Most organisms are adapted to maintain homeostasis in their native environment.

Limiting Factors Environmental factors (biotic or abiotic) that affect an organism’s population, reproduction, distribution, or ability to survive in its environment Factors that limit one population in a community may also have an indirect effect on another population. Abiotic (non-living) factors Sunlight, temperature, climate, water, food, soil, space, fire Biotic (living) factors Plants and animals

Range of Tolerance The ability of any organism to survive when subjected to abiotic or biotic factors is called tolerance. Each organism has an upper and lower limit to what they can tolerate.

Ecological Succession Ecosystems are constantly changing. Succession is the orderly, natural changes and species replacements that take place in the communities of an ecosystem over time. Occurs in stages: different species at different stages create conditions that are suitable for some organisms and not for others. Can take decades to centuries

Primary Succession The colonization of new land that is exposed by avalanches, volcanoes, or glaciers by pioneer organisms. Establishment of a community in an area of exposed rock that does not have any topsoil. Lichens (combo of fungus and algae) and some mosses are among the first organisms to appear because they can grow on rock.

Primary Succession Pioneer species are the first species in an area. As pioneer species die, their decaying organic materials, along with bits of sediment from the rocks, make up the first stage of soil development. Eventually enough soil will be present so that trees and shrubs can grow. Primary succession eventually slows down and the community becomes fairly stable.

Secondary Succession A stable, mature community that undergoes little or no change in species is called a climax community. Eventually, things will begin to change. Secondary succession refers to the sequence of community changes that take place after a community is disrupted by natural disasters or human actions. Happens in areas that previously contained life. Takes less time than primary succession

Terrestrial Biomes: Lesson Objectives Relate latitude and the 3 major climate zones. Describe the major abiotic factors that determine the location of a terrestrial biome. Distinguish among terrestrial biomes based on climate and biotic factors.

Effects of Latitude and Climate You are affected by weather and climate. Weather is the condition of the atmosphere at a specific place and time. The distance of any point on the surface of Earth north or south from the equator is latitude. Light from the sun strikes Earth more directly at the equator than at the poles.

Effects of Latitude and Climate Earth’s surface is heated differently in different areas. The average weather conditions in an area, including temperature and precipitation, describe the area’s climate. Latitude has an effect on climate, as well as elevation, landmasses, and ocean currents.

Major Land Biomes Biomes are classified by: Their plant life Temperature Precipitation Animal species

Tundra Average precipitation: 15-25 cm/year Temperature range:-34°C-12°C Plants: short grasses, shrubs Animals: caribou, polar bears, birds, insects, wolves, salmon, trout Location: south of the polar ice caps in the Northern Hemisphere, North/South pole Abiotic factors: soggy summers; permafrost; cold and dark much of the year

Taiga Boreal forest Average precipitation: 30-84 cm/year Temperature range: -54°C – 21°C Plants: spruce and fir trees (conifers), few deciduous trees, small shrubs Animals: birds, moose, beavers, deer, wolverines, mountain lions Location: Northern part of North America, Europe, and Asia Abiotic factors: summers are short and moist; winters are long, cold, and dry

Temperate Forest Average precipitation: 75-150 cm/year Temperature range:-30°C-30°C Plants: oak, beech, and maple trees, shrubs Animals: squirrels, rabbits, skunks, birds, deer, foxes, black bears Location: South of the boreal forests in eastern North America, eastern Asia, Australia, and Europe Abiotic factors: well-defined seasons, summers are hot, winters are cold

Woodlands/Shrublands Average precipitation: 38-100 cm/year Temperature range: 10°C-40°C Plants: evergreen shrubs, corn oak Animals: foxes, jackrabbits, birds, bobcats, coyotes, lizards, snakes, butterflies Location: surrounds the Mediterranean Sea, western coasts of North and South America, South Africa, and Australia Abiotic factors: summers are very hot and dry; winters are cool and wet

Grassland Average precipitation: 50-89 cm/year Temperature range: -40°C - 38°C Plants: grasses and herbs Animals: gazelles, bison, horses, lions, deer, mice, coyotes, foxes, wolves, birds, quail, snakes, grasshoppers, spiders Location: North America (largest part), South America, Asia, Africa, and Australia Abiotic factors: summers are hot, winters are cold, moderate rainfall, fires possible

Desert Average precipitation: 2-26 cm/year – driest biome Temperature range: high 20°C – 49°C, low -18°C – 10°C Plants: cacti, Joshua trees, succulents Animals: lizards, bobcats, birds, tortoises, rats, antelope, desert toads Location: every continent except Europe Abiotic factors: varying temperatures, low rainfall

Tropical Savanna Average precipitation: 50-130 cm/year Temperature range: 20°C – 30°C Plants: grasses and scattered trees Animals: lions, hyenas, cheetahs, elephants, giraffes, zebras, birds, insects Location: Africa, South America, and Australia Abiotic factors: summers are hot and rainy, winters are cool and dry

Tropical Rain Forest Average precipitatio: 200-1000 cm/year Temperature range: 24°C – 27°C Plant: broadleaf evergreens, bamboo, sugar cane Animals: chimpanzees, Bengal tigers, elephants, orangutans, bats, toucans, sloth, cobra snakes Location: Central and South America, southern Asia, western Africa, and northeastern Australia Abiotic factors: humid all year, hot and wet

Other Terrestrial Areas Mountains have abiotic conditions that change with increasing elevation, allowing many communities to exist. Polar regions border the tundra at high latitudes and are cold all year.

Aquatic Ecosystems: Lesson Objectives Identify the major abiotic factors that determine the aquatic ecosystems. Recognize that freshwater ecosystems are characterized by depth and water flow. Identify transitional aquatic ecosystems and their importance. Distinguish the zones of marine ecosystems.

Freshwater Ecosystems Major ecosystems include ponds, lakes, streams, rivers, and wetlands Plants and animals are adapted to the low salt content and unable to survive in high salt content 2.5% of water on Earth is freshwater 68.9% is locked in glaciers, 30.8% is groundwater, and 0.3% is lakes, ponds, rivers, streams, and wetlands

Rivers and Streams Water flows in one direction Characteristics change during the journey from the source to the mouth Rapid waters have fewer species and less sediment and organic materials Plants and animals must be adapted to withstand the constant water current

Lakes and Ponds An inland body of standing water Divided into 3 zones: Littoral zone – area closest to the shore, shallow, lots of photosynthetic organisms Limnetic zone – open water area that is well lit and is dominated by plankton Profundal zone – minimal light penetration, much colder, lower in oxygen, limited number of species

Transitional Aquatic Ecosystems Many aquatic environments are a combination of two or more different environments Wetlands: marshes, swamps, and bogs; plant species grow in the humid, moist conditions; lots of animal diversity Estuaries: among most diverse ecosystem; formed where freshwater and saltwater meet; many aquatic plants and detritivores

Marine Biomes The oceans contain the largest amount of biomass, or living material, of any biome. Most of the biomass is made of extremely small organisms. Separated into shallow, sunlit zones and deeper, unlighted zones. The portion of marine biome that is shallow enough for sunlight to penetrate is called the photic zone. Ex. coastlines

Marine Biomes Deeper water that never receives sunlight makes up the aphotic zone. The benthic zone is the area along the ocean floor that consists of sand, silt, and dead organisms. The deepest region of the ocean is the abyssal zone. Twice a day, the gravitational pull of the sun and moon causes the rise and fall of the oceans. The intertidal zone is the area between low tide and high tide.

Marine Biomes Plankton are small organisms that live in the waters of the photic zone. Zooplankton are tiny animals that feed on plankton. Coral reefs are one of the most beautiful and diverse biomes to study and are found only in warm water about 40 meters deep.