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ECOLOGY & the ENVIRONMENT. ECOLOGY. The study of interactions among organisms & their environment Ecologists divide environmental factors that influence organisms into 2 groups: ABIOTIC and BIOTIC. ABIOTIC. NONLIVING PARTS OF THE ENVIRONMENT Ex: Water, light, temperature, air, soil
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ECOLOGY & the ENVIRONMENT
ECOLOGY • The study of interactions among organisms & their environment • Ecologists divide environmental factors that influence organisms into 2 groups: ABIOTIC and BIOTIC.
ABIOTIC • NONLIVING PARTS OF THE ENVIRONMENT • Ex: Water, light, temperature, air, soil • Air is a mixture of 3 main gases: oxygen, carbon dioxide, & nitrogen(used by plants & animals
Soil type is determined by the amounts of sand, humus, & clay that it contains • Humus: decaying matter found in soil
BIOTIC • Living or once-living organisms in the environment • Can be arranged into levels of organization:
1. organism • 1 individual from a population • Example: catfish
2. Population • All the individuals of one species that live in the same area at the same time. • Example: All the catfish living in a lake at the same time
3. community • Populations of different species that interact in some way • Example: Population of bass and all the species they interact with it
4. ecosystem • All the communities in an area & the abiotic factors that affect them • Example: lake, pond, coral reef, forest, etc.
5. Biome • Large region with plants & animals well adapted to soil & climate of the region • Example: Mountain, rainforests, tundra, desert, grasslands, temperate forests (where we live)
6. biosphere • All the ecosystems on earth; the part of the earth that supports life • Example: Top part of the earth’s crust, all the waters that cover the Earth’s surface, the surrounding atmosphere, & all the biomes.
1. Population size • The number of individuals in a population
2. Population Density • The number of individuals in a population that occupy a definite area
Classroom population density • Length of room (m) X width (m) # of students =A (in m2) = how much space each person has
3. Population spacing • How organisms are arranged in a given area • Can be evenly, random, or clumped clumped EVEN random
4. Limiting factors • Any biotic or abiotic factor that limits the number of individuals in a population • Ex: drought, fewer plants, fewer nesting sites, predators
Food, water, & space are all factors in the growth populations in an ecosystem • If an environment had no limiting factors, the population would INCREASE.
5. Carrying capacity • Largest number of individuals of a species that an environment can support & maintain for a long period of time.
Energy flow through ecosystems • Most of the interactions among members of different species occur when one organism feeds on another
When one organism is food for another organism, some of the energy in the first organism (the food) is transferred to the second organism (the eater).
producers • Organisms that take in & use energy from the sun or some other source to produce food. • Another name for producer is autotroph. • Examples: algae & plants
Consumers • Organisms that take in energy when they feed on producers or other consumers. • Another name for consumer is heterotroph.
decomposers • Organisms that take in energy from organisms that have died by breaking down the remains of organisms.
Scavenger • Organisms that feed on dead animals or plant material present in its habitat.
Are producers Are consumers and decomposers Plants, bacteria, and algae Need food Animals, humans, monkeys Both are living things Get food from autotrophs Make food from water, sunlight, and CO² Autotrophs Heterotrophs Need water, sunlight, and air Means “self nutrition” Means “other nutrition” Characteristics of Autotrophs vs. Heterotrophs
Movement of energy through a community can be diagrammed as a food chain or food web.
Food chain • Simple way of showing how energy passes from one organism to another. • Usually 3 or 4 links
Example of food chain: • Water plant insects bluegill bass • Grass grasshopper frog snake owl
Energy pyramid • Compares energy available at each level of the food chain in an ecosystem • As you move from level to level, energy decreases.
2. Food web • Series of overlapping food chains that exist in an ecosystem • More complete model of feeding relationships.
Primary Consumer-an animal that feeds on plants; a herbivores • Secondary Consumer-an animal that eats primary consumers and plants. They are omnivores. • Tertiary Consumer-an animal that eats secondary consumers. They are carnivores.
Other Ecological Terms to Know: • Symbiosisis a close relationship that may occur when two organisms of different species live together. • There are several different kinds of symbiotic relationships: 1) Mutualism: Both species benefit. The two organisms help each other. An example would be a honey bee and a dandelion. The honey bee gets to eat the pollen from the flower. The dandelion uses the bee to spread its pollen to another flower.
More Ecological Terms cont. 2) Commensalism: One species benefits. The other species is unaffected. A common example is an animal using a plant for shelter. An American Robin benefits by building its nest in a Red Maple tree. The tree is unaffected. 3) Parasitism: Ones species benefits. The other species is harmed. An example would be a deer tick and a White-tailed Deer. The tick gets food from the deer without killing it. The deer is harmed by losing blood to the tick, and possibly by getting an infected wound or disease. 4) Predation: A predator/ prey relationship. An example is an owl hunting a mouse. 5) Cooperation: Organisms work together for a common or mutual benefit. An example would be a group of lionesses hunting prey.
