Ecology

Ecology

All Materials © Cmassengale 

Ecology is the study of interactions between organisms (biotic part) and their nonliving environment (abiotic factors)

Biotic factors includes plants, animals, fungi, & microorganisms. They may be producers, consumers, or decomposers.

Abiotic factors include climate, soil, temperature, water, air, sunlight, humidity, pH, and atmospheric gases.

Habitat is the place a plant or animal lives, while its niche is its total way of life.

Life is organized into levels:

Organism (any single living thing)

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            Population (members of the same species living in one place)

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                    Community (all the populations living in an area)

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        Ecosystem (community living in a similar habitat such as a forest)

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Biomes (ecosystems covering wide areas & with similar climates & organisms)

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Biosphere ( all the living & nonliving things on earth)

Producers:

Consumers:

Decomposers:

Sunlight is the ultimate energy for all life on earth, but only producers can get their energy directly from the sun.

Trophic levels are feeding levels of producers & consumers in an ecosystem:

Food chains & food webs:

Three main elements that must move through an ecosystem:

Water or Hydrologic Cycle:

Steps in the water Cycle:

Evaporation                                         Transpiration
(water loss from lakes, rivers, oceans…)          (water loss from plant leaves)

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Condensation
(water vapor forms clouds)

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Precipitation
(water returns to earth as sleet, rain, snow…)

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Surface Runoff
(returns water to bodies of water or to groundwater)

Carbon Cycle:

Carbon Cycle Steps:

Plant leaves take carbon dioxide from air

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Plants store carbon in carbohydrates or starches
(photosynthesis)

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Plants & animals release carbon dioxide back into the air
(cellular respiration)

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Decomposers return carbon to environment
(decomposition)

Nitrogen:

Steps in the Nitrogen Cycle:

Cyanobacteria & Rhizobium take nitrogen from air
(nitrogen fixation)

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Convert nitrogen gas into ammonia

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Nitrifying bacteria in soil change ammonia into nitrates

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Plants can absorb & use nitrates to make proteins

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Consumers eat plants & get proteins containing nitrogen

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Decomposers break down dead organisms & return nitrogen to air
(called ammonification)

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Anaerobic bacteria in soil release nitrogen from nitrates into air
(called denitrification)

Three main types of ecosystems:

Terrestrial ecosystems are divided into 7 biomes with similar climates & organisms

Seven Terrestrial Biomes:

Tundra:

Taiga:

• Coniferous forest
• Extends across northern Eurasia & North America
• Contains conifers or evergreens (spruce, cedar, fir, pine …)
• Needle like leaves withstand weight of snow
• Bear, deer, moose, wolves, mountain lions …
• Sequoia or redwood (largest conifer) grows here
• Bristle cone pine oldest living conifer found here

Temperate Deciduous Forest:

• South of taiga in North America, eastern Asia, & Europe
• High annual rainfall (75-150 cm)
• Moderate temperatures
• Well-defined seasons of about equal length
• Trees loose leaves in winter (deciduous)
• Show stratification (plant layers):
  1. Canopy – broad leaf deciduous trees forming uppermost layer
  2. Under story – shrubs
  3. Forest Floor – herbaceous plants
• Songbirds, deer, rabbits, foxes, squirrels, frogs 7 toads, lizards …

Tropical Rain forest:

• Near equator
• Warm climate (20 -25 degrees C)
• Plentiful rainfall (190 cm/year)
• Contains the greatest diversity of plants & animals
• Insects, monkeys & apes, snakes, tropical birds, leopards…
• Animals & plants brightly colored
• Poor soil for agriculture

Grasslands:

• Mostly grasses with a few trees due to less rainfall
• Moderate climates
• Good for agricultural crops
• Grazing & burrowing animals dominate
• Also called prairies

Savanna:

• Tropical grasslands
• Warm climate & rainy season
• Antelope, zebra, lions, wildebeests, hyenas, elephants…
• Suffer from floods & drought

Deserts:

• Low annual rainfall
• Subject to strong winds
• Days usually hot & nights cold
• Sahara desert is without vegetation
• Succulents such as cacti & other water storing plants
• Most animals nocturnal
• Lizards, snakes, roadrunners, insects, tarantula, hawks, rodents, coyotes…

Aquatic Biomes:

• May be freshwater or saltwater
• Wetlands near oceans have brackish water (mixture of fresh & salt waters)
• Part of the part water or hydrologic cycle
• Often polluted by man’s activities

Lakes & Rivers:

• Freshwater
• Oligotrophic lakes are nutrient poor (catfish, carp…)
• Eutrophic lake are nutrient rich (trout, bass…)
• Deep lakes have layers or strata where different plants & animals live
• Phototropic organisms in upper layers for light
• Estuary at mouth of river contains brackish water

Ocean Zones:

• Intertidal zone
  1. Along shoreline
  2. Wave action
  3. Lots of light so many producers
  4. Starfish, sand dollars…
• Neritic Zone
  1. Ocean water above continental shelf
  2. Coral reef found here
  3. Surrounds continents & receives light in upper layers
• Oceanic Zone
  1. Beyond continental shelf
  2. Deepest area (up to 7 miles)
  3. Bottom doesn’t receive light so animals adapted to darkness (many produce their own light, feed on other animals…)
  4. Deepest area called abyss
  5. Upper area gets light & called the photic zone (lots of seaweed here)
  6. Floaters called plankton (microscopic organisms)
  7. Swimmers such as fish called nekton
  8. Bottom dwellers called benthos