Introduction:
v What is ecology?
Ø How life processes have adapted to its environment
Ø How organisms are distributed in various environments
Ø How materials and energy is moved through systems of interacting organisms and their environment
Ø How an ecosystem changes over time
Ø How biodiversity is influenced by the environment
v Scales and level of complexity
Ø Individual
Ø Population
Ø Community
§ Is an assemblage of two or more populations occupying the same area
Ø Ecosystem
Ø Biome
Ø Biosphere
v Examples of biomes
Ø Desert
Ø Savanna
Ø Boreal forest
Ø Intertidal zone
Ø Tropical rainforest
Ø Coral reef
v Factors influencing ecology
Ø Abiotic factors
§ Temperature
§ Rainfall
§ Light intensity
§ Salinity
§ Humidity
§ Wind speed
§ Wave action
§ pH
Ø Biotic factors
§ Abundance of prey
§ Presence of predators
§ Competition
Ecological Interactions:
v Mutualism
Ø Both organisms A and B benefit from the interaction between them
§ Clownfish and sea anemone
§ Ants and aphids
§ Egyptian plover and crocodile
§ Cleaner shrimps and eel
v Commensalism
Ø Only organism A benefit from the interaction between them, while organism B receives no advantage or disadvantage
§ Epiphytes and rain tree
§ Cattle egret and cattle
§ Remora and shark
§ Barnacles and scallop
v Exploitative relationships
Ø Only organism A benefit from the interaction between them, while B is harmed in some way or may even die from the relationship
§ Predation: Cheetah and gazelle
§ Herbivory: Zebra and grass
§ Parasitism: Tree ear fungus and tree
v Competition
Ø Both suffer some form of disadvantage
§ Great blue heron, great egret and snowy egret hunting fish
§ Reindeers competing for their mate
§ Trees competing for light
Energy and Productivity
v Food Chain
Ø Producers: Plants
§ Obtain energy directly from the sun
Ø Primary consumers: Herbivores
§ Obtain energy indirectly from the sun
Ø Secondary consumers
§ Obtain energy indirectly from the sun
v Dietary
Ø Herbivores
§ Have a strict diet consisting of plant material only
Ø Carnivores
§ Have a strict diet consisting of the flesh of other animals
Ø Omnivores
§ Have a diet of both plant material and flesh of other animals
v Decomposers
Ø All organisms will die eventually
Ø Bodies will undergo decomposition
Ø Will be broken down into simpler substances
Ø Accelerated by decomposers
Ø Are organisms that feed on dead plants and animals, breaking them down into simpler substances
v Non-cyclic flow of energy
Ø Energy is always lost along a food chain
Ø Cannot be recycled
Ø Gets lost through the form of heat and other life processes
Nutrient cycles:
v Carbon cycle
Ø Carbon dioxide in water precipitate to form limestone
§ Plants take up carbon dioxide and convert it to carbohydrates
· Carbohydrates could be:
¨ Sent back to the atmosphere through respiration
¨ Be present in the plant when it dies
Ø Respired by decomposers
Ø Buried and turn into fossil fuels
§ Burn fossil fuels and release carbon dioxide in the air
¨ Eaten by an animal
Ø Sent back to the atmosphere through respiration
§ Taken up by plant through photosynthesis
§ Dissolved in the oceans
¨ Be present in the animal when it dies
Ø Respired by decomposers
Ø Buried and turn into fossil fuels
§ Burn fossil fuels and release carbon dioxide in the air
v Nitrogen cycle
Ø Nitrogen gas in air
§ Lightning can turn it to nitrate
§ Nitrogen fixing bacteria fix it to nitrate or ammonia
· Plants take up nitrate and convert it to amino acids
¨ Eaten by animals
Ø When die, ammonia released back into soil
§ Nitrite bacteria change ammonia to nitrite
· Nitrate bacteria change nitrite into nitrate
Conservation:
v Why must we conserve?
Ø Prevent extinction
Ø Maintain stability in ecosystem
Ø Maintain large gene pool and preserve useful genes
Ø Sources of raw materials
Ø Scientific value
Ø Recreational purposes
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