ECOLOGYECOLOGY

The Study of Interactions between The Study of Interactions between Organisms and their EnvironmentOrganisms and their Environment

Ecology VocabularyEcology 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 FACTORSECOSYSTEM 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-livingtemperature, sunlight, water, minerals

Trophic LevelsTrophic Levels

Trophic LevelsTrophic 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 FLOWENERGY 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 WebArctic Marine Food Web

Biomass PyramidBiomass Pyramid

Energy Pyramid

Kruger Park Battle

Growth of PopulationsGrowth 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 TimePopulation 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 InteractionCommunity 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 InteractionsPredator-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.

PredationPredation

Predator – Prey DynamicsPredator – Prey Dynamics

SymbiosisSymbiosis

• 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 algaeFig 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 mammalsBed Bugs-Feed at night on unsuspecting Humans

MutualismMutualism

• Both organisms BENEFIT

from the interactionRed billed oxpecker feeds on the ticksOff the Impalas coat (Africa) Clownfish and Sea Anemone

Coral and Zooxanthellae

Crocodile and plover mutualistic Crocodile and plover mutualistic relationship. Plover cleans relationship. Plover cleans

crocodiles teeth. crocodiles teeth.

Commensalism – Commensalism –

• one IS HELPED but the other is NOT harmed

• Ex. Birds nest in trees

Hermit crab withSea Anemone living on it

ParasitismParasitism

• The other is

HARMED

One organism

BENEFITS

Malaria

Predator Prey Co-evolutionPredator 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-EvolutionCo-Evolution

• Predator /prey interactions

POISON IVY – protected from herbivores

WARNING coloration says, “Don’t mess with me !!”

CamouflageCamouflagePROTECTIVE

coloration

Stick insects found in Australia

caterpillar

MimicryMimicry

• Similar colors

• Similar DEFENSES

Wasp/yellow jacket- no hair-keep stinging you

Bee-hair on-some don’t sting others do.

Mimicry- Fooled Ya!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