The Study of Interactions between Organisms (Living Things) and Their Environment

Ecology Vocabulary Population: a particular species in an area Community: a group of populations in an area Ecosystem: a community and 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 organism in the environment (what you eat, what you do)

ECOSYSTEM FACTORS BIOTIC: Living (animals, plant, microbes) AUTOTROPHS (produce food) Example: plants, algae HETEROTROPHS- (need to get food—cannot produce it)Example : animals Consumers- (consume food/eat ) Decomposers-(breakdown material) bacteria, fungi Scavengers (vulture) are not decomposers because they are not returning nutrients to the soil ABIOTIC: Non-living (temperature, sunlight, water, minerals)

Biodiversity

Keystone Species Hold Together a Dynamic Ecosystem

Trophic Levels

Trophic Levels—(Feeding 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) Detritovores

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 at each trophic level.

FOREST FOOD WEB

Arctic Marine Food Web

Biomass Pyramid

Energy Pyramid

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—leads to: Logistic Growth 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

Exponential vs. Logistic Growth

Competition- when populations require use of limited resources Predator/prey- when one population depends upon another for food Symbiosis- when two population’s Niches interact with each other

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 Close relationship between 2 or more organisms of different species. Three major types: Mutualism, Commensalism and Parasitism. 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

Type of relationship Species harmed Species benefits Species neutral Commensalism Parasitism Mutualism = 1 species \

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 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

Ecological Succession The natural progression of SPECIES and their EFFECTS on the environment PIONEER Species – the first to invade a new environment (bare rock) MODIFICATIONS by the first group leads to the second, the second the third, etc. The CLIMAX species will end the succession. Primary succession-occurs on barren rock Secondary succession occurs on an area that has been altered but not devoid of life

Forest Succession

Lake Succession 1. LAKE community 2. Sedimentation due to EROSION 3. SWAMP community forms 4. Eventually a FOREST community may form 5. Forest succession can occur

Nutrient Recycling Carbon and Oxygen: CO2, O2 (AIR) Water: H2O (SOLID, LIQUID, GAS) Nitrogen: N2 (AIR) Other Minerals : MAGNESIUM, CALCIUM, IRON, ZINC, COPPER, SILICA, ETC.

Carbon Cycle Atmospheric CARBON DIOXIDE Autotrophs- (Plants) change CO2 to O2 Heterotrophs-(animals) use O2 release CO2 Decomposers-(bacteria,fungus)- BREAK DOWN organic materials and release CO2 Burning of FOSSIL FUELS- RELEASE CO2

Water Cycle Evaporation- LIQUID TO WATER VAPOR Transpiration- EVAPORATION THROUGH PLANTS stomates Condensation and Precipitation- RAIN,SNOW, SLEET, HAIL etc. Runoff and Groundwater INFILTRATION Liquid water on the surface LAKES, STREAMS, OCEANS etc.

Nitrogen cycle Nitrogen in the Atmosphere -78% of Air Nitrogen fixers- bacteria Plants and animals-plants absorb nitrates and animals eat plants Decomposers-bacteria that help with decay Nitrifying Bacteria Denitrifying Bacteria

Only in certain bacteria and industrial technologies can fix nitrogen. Nitrogen fixation-convert atmospheric nitrogen (N 2 ) into ammonium (NH 4 + ) which can be used to make organic compounds like amino acids. N  NH 4 + +

Nitrogen Fixation Nitrogen-fixing bacteria: Some live in a symbiotic relationship with plants of the legume family (e.g., soybeans, clover, peanuts).

Other Minerals Rocks and Soil CONTAIN MINERALS Erosion RELEASES MINERALS Water dissolves MINERALS Plants and Algae uptake MINERALS Animals consume plants and animals Decomposers LEAVE MINERALS IN SOIL

Ex: DDT & Bald Eagles Toxins in food chains- While energy decreases as it moves up the food chain, toxins increase in potency. This is called biological magnification