Principles of Ecology

What is ecology? The study of the interactions between organisms and their environments.

Biosphere The part of the earth that supports life Air (Atmosphere) Water (Hydrosphere) Land (Lithosphere) Variety of organisms in a wide range of conditions that they are adapted to survive in

Biotic vs. Abiotic Biotic factors: living factors in an environment Ex: Abiotic factors: nonliving factors in an environment Ex:

Levels of Organization Organism Population Biological Community Ecosystem Biome

Population- All members of a species living in the same location at the same time Individuals must compete to survive What limits the size of a population? Organism- One member of a species The lowest level of organization that ecologists study

Community- A group of populations that interact in the same location at the same time Includes all plants, animals, bacteria, fungi, and protists May or may not compete for resources

Ecosystem- A biological community and all the biotic and abiotic factors that affect it Boundaries are defined by scientists Can change Can overlap

Biome- A large group of ecosystems that have the same climate similar types of communities

Ecosystem Interactions Habitat: an area where an organism lives Tree Grove of trees Niche: the role an organism has in its environment How it meets its need for Food Shelter Survival Reproduction

Community Interactions Each organism depends on and competes with other organisms. Competition: occurs when organisms need to use same resource at the same time Food Water Space Light

Symbiosis: relationship in which two organisms live in close association to each other Mutualism: Two species live together and benefit from each other Ex: Termite and protozoa in stomach Commensalism: One organism is helped and the other is not helped or harmed Ex: Remora and whale sharks Parasitism: One organism is helped and the other is harmed Ex: Mosquitoes and humans

Symbiosis Oxpecker and Cattle (and ticks) White winged dove and Saguaro Cactus

Energy in an Ecosystem Autotrophs: organisms that get energy from sunlight or inorganic substances to produce food Producers Heterotrophs: organisms that obtain energy by consuming other organisms Consumers

Consumers Herbivore: Consumes only plants Ex: cows, rabbits, grasshoppers Carnivore: Eats other heterotrophs Ex: lions, wolves Omnivore: Eat both plants and animals Ex: humans, bears, mockingbirds Detritivore: Eats dead things and return nutrients to the environment Ex: hyenas, vultures, fungi, bacteria Why are they important? What would happen without them?

Food Chains Shows how energy flows through an ecosystem Flow on energy is one way into the consumer

Food Web Shows feeding relationships in an ecosystem Contains several food chains

Pyramid of Energy Shows energy flow by trophic levels Indicates the amount of energy available to next level (~10%)

Pyramid of Biomass Shows the amount of biomass consumed by the level above it At each level there is less energy available to support organisms

Nutrient Cycles producer  consumer detritivore  environment Nutrients cycle through biosphere Needed for organisms to survive Water Carbon Nitrogen Phosphorous producer  consumer detritivore  environment

Communities, Biomes, and Ecosystems

Limiting Factor Any factor that restricts the numbers, reproduction, or distribution of organisms Sunlight Climate Water Fire Space Other plant or animal species Factors that limit one species might enable another

Range of Tolerance Upper and lower limit of tolerance that an organism can survive when exposed to certain factors Optimum zone: range that is best suited for the organism Zone of physiological stress: zone between optimum zone and tolerance limits

Range of Tolerance

Succession

Ecological Succession Primary Succession Secondary Succession Begins with bare rock Ex: lava flow forms rock Pioneer Species: the first organisms to appear Lichen- creates soil to support other life Might take hundreds of years for ecosystem to balanced Climax Community: a stable, mature community; little change in number of species Scientists now reject – always changing Begins with disrupted community; soil present Fire, flood Over time species belong to community are likely to return Pioneer communities quickly progress Ends in climax community The process of one community replacing another as a result of changing factors

1 2 3 Primary Succession Bare rock with lichen Grasses and shrubs Forest community 3

Secondary Succession of an abandoned farm field in North Carolina

Secondary Succession - Fire Primary Succession

Succession in a Pond Eventually the pond fills in with soil Some last only a couple weeks others for thousands of years Ponds go from: Oligotrophic (nutrient poor) to Eutrophic (nutrient rich)

Biomes Land Aquatic Tundra Taiga (Boreal Forest) Temperate Deciduous Forests Grasslands Deserts Savannas Tropical Rain Forests Fresh Water Transitional Marine

You are going to get to do Biome Projects next week!