ECOLOGY The Study of Interactions between Organisms and their Environment

Ecology Vocabulary Population: a particular species in an area Community: a group of populations in an area Ecosystem: a community plus its non-living (abiotic) environment Biosphere: all regions of the planet inhabited by populations Habitat: The place a population lives Niche: the role of the population in the environment (what you eat, what you do)

ECOSYSTEM FACTORS BIOTIC: Living (animals, plant, microbes) AUTOTROPHS (produce food) plants HETEROTROPHS-(need to get food) consumers- (eat ) Decomposers-(breakdown organics)Bacteria, fungi A scavenger (vulture) is not a decomposer because they are not returning nutrients to the soil ABIOTIC:Non-living temperature, sunlight, water, minerals

Trophic Levels

Primary Producers: The autotrophs that capture energy to make food (Plants) Primary Consumers: heterotrophs that eat autotrophs (herbivores) Secondary Consumers: heterotrophs that eat other heterotrophs (carnivores) Higher Level Consumers: carnivores that eat other carnivores Decomposers: consumers of dead organic material ( Bacteria, Fungi)

ENERGY FLOW Food chains: a specific energy pathway Food webs: complex energy interactions found in an ecosystem. Energy pyramids: representation of the total energy available to a trophic level.

FOREST FOOD WEB

Arctic Marine Food Web

Biomass Pyramid

Energy Pyramid

Kruger Park Battle Kruger Park Battle

Growth of Populations Exponential Growth :occurs when individuals in a population reproduce at a constant rate. (in natural populations this does not occur for very long) Carrying Capacity of the Environment: The maximum population that a particular environment can support Limiting Factors : those environmental factors that keep a population at the carrying capacity, like food, predators, amount of water, how much land there is

Population Growth over Time

In 1944, 20 reindeer were brought to St. Matthew Island for an emergency food source.The Island is off the coast of Alaska in the Bering Sea. Initially there were abundant food sources, and the reindeer population increased dramatically. There were no predators to cull the population. However, about 20 years later, the reindeer had overshot the food carrying capacity of the island, and there was a sudden, massive die-off. About 99% of the reindeer died of starvation. Exponential growth can lead to massive die-off

Carrying capacity of the Environment

Community Interaction competition

Competition- when populations require use of limited resources Predator/prey- when one population depends upon another for food Symbiosis- when two populations Niche –Coincide with each other

Competition- Resource food or population may overlap

Predator-Prey Interactions Predators : Organisms that catch and consume other organisms Prey : organisms that get consumed. Top Predator : the organism within a food chain or web that is not eaten by any other organism.

Predation

Predator – Prey Dynamics

Symbiosis When TWO or more species interact so closely that one or more of them is NECESSARY for the other’s survival. Examples: Coral and zooxanthellae algae Fig trees and fig wasps(only way fig tree is pollinated. Fig enters fig and deposits eggs and pollen she brought along from another fig) Tape worms and humans (from undercooked meat, mostly pork.Live inside your intestines.Can grow 50ft long and live up to 20 years inside you) Fleas and hairy mammals Bed Bugs-Feed at night on unsuspecting Humans

Mutualism Both organisms BENEFIT from the interaction Red billed oxpecker feeds on the ticks Off the Impalas coat (Africa) Clownfish and Sea Anemone Coral and Zooxanthellae

Crocodile and plover mutualistic relationship. Plover cleans crocodiles teeth.

Commensalism – one IS HELPED but the other is NOT harmed Ex. Birds nest in trees Hermit crab with Sea Anemone living on it

Parasitism The other is HARMED One organism BENEFITS Malaria

Predator Prey Co-evolution Protection from Predation (for prey) –Poison : the production of toxins –Camouflage : protective coloration –Mimicry: look alikes Adaptations to overcome protections (for predators) –Intolerance to poisons : immunity –Use of senses other than sight: hearing, smell

Co-Evolution Predator /prey interactions POISON IVY – protected from herbivores WARNING coloration says, “Don’t mess with me !!”

Camouflage PROTECTIVE coloration Stick insects found in Australia caterpillar

Mimicry Similar colors Similar DEFENSES Wasp/yellow jacket- no hair-keep stinging you Bee-hair on-some don’t sting others do.

Mimicry- Fooled Ya! King snake (not poisonous) Coral snake (VERY poisonous) If red touches yellow you’re a dead fellow If red touches black you’re a fine Jack