unit 1: Ecosystems

Flashcards on Ecosystems, Niches, Symbiosis, Biomes, and Cycles

Ecosystem

A community of living organisms (plants, animals, and microbes) that interact with each other and with their physical environment (air, water, soil).

Organism

A single, individual living entity (e.g., one bird).

Species

A group of similar organisms capable of interbreeding and producing fertile offspring (e.g., all blue jays).

Population

A group of organisms of the same species living in the same area at the same time (e.g., a flock of blue jays in a backyard).

Community

An interacting group of various species in a common location (e.g., birds, squirrels, and trees in a park).

Niche

The role or function of an organism or species in an ecosystem, including its habitat, food sources, and interactions with other species.

Generalists

Organisms that can thrive in a wide variety of environmental conditions and have a diverse diet (e.g., raccoons and humans).

Specialists

Organisms that can only thrive in a narrow range of environmental conditions or have a very limited diet (e.g., pandas that eat only bamboo).

Mutualism

A symbiotic relationship in which both species benefit (e.g., bee and flower).

Parasitism

A symbiotic relationship in which one species benefits and the other is harmed (e.g., a tick on a dog).

Commensalism

A symbiotic relationship in which one species benefits and the other is neither harmed nor helped (e.g., a bird nesting in a tree).

Amensalism

A relationship where one organism is harmed or inhibited and the other is unaffected (e.g., a tree poisons other plants nearby).

Predator

An animal that hunts and kills other animals for food (e.g., a lion).

Prey

An animal that is hunted and killed by another for food (e.g., a zebra).

Saprotrophs

Organisms that obtain nutrients by feeding on dead or decaying organic matter (e.g., mushrooms and bacteria).

Law of Tolerance

The principle that organisms can only survive within a specific range of environmental conditions, such as temperature, moisture, and salinity.

Biome

A large geographic area characterized by specific climate conditions, animal populations, and plant species.

Aestivation

A state of dormancy similar to hibernation, but occurring during periods of heat and dryness.

Closed Canopy

A forest where the tree tops touch and block out most of the sunlight.

Open Canopy

A forest where there is more space between the trees, allowing some light to get through.

Permafrost

Ground that is permanently frozen.

Phytoplankton

Microscopic plants that grow in the ocean and start the food chain.

Zooxanthellae

Plant buddies that help corals.

Carbon Sink

A reservoir that accumulates and stores carbon dioxide from the atmosphere.

Nitrogen Fixation

The conversion of atmospheric nitrogen into a form that plants can use.

Nitrification

The two-step process where bacteria converts ammonia into nitrite, then into nitrate.

Assimilation

The process by which plants absorb nitrate or ammonia through their roots to grow.

Ammonification

The process by which bacteria turn dead things and waste into Ammonia (NH3).

Denitrification

The process by which bacteria converts nitrates back into Nitrogen gas and returns it to the atmosphere.

Weathering

The process by which rain and wind break down rocks and release phosphorous into the soil.

Evaporation

The process where the sun heats up water in oceans, lakes, and puddles, and turns it into a gas (vapor) that goes into the air.

Condensation

The process where water vapor cools down in the sky and makes clouds.

Precipitation

The process where water falls back down as rain, snow, sleet, or hail.

Infiltration

The process where some water soaks into the ground.

Runoff

The process where the rest of the water (after infiltration) runs across land into rivers, lakes, and oceans.

Evapotranspiration

The process where plants 'sweat' water through their leaves and send it into the air, too.

Primary Productivity

The rate at which plants make food energy using sunlight.

Gross Primary Production (GPP)

All the energy that plants make.

Net Primary Production (NPP)

The extra energy left over after the plant eats what it needs.

Trophic Levels

The steps in the food chain.