- Slides: 22
What is Ecology? Ecology is the study of the interactions of organisms with one another and with their physical environment. Biosphere - part of the Earth in which life exists. Includes land, air, and water as well as life. Living organisms are NOT distributed uniformly throughout the biosphere.
The biosphere is large… …So ecologists work with smaller units called ecosystems. Ecosystem - consists of an area’s physical features and living organisms. System- a set of interacting or interdependent components that form an integrated whole Abiotic Ex. factors - physical features elevation, humidity, rainfall (SWATS: Biotic Ex. soil, water, air, temp, sunlight) factors - living organisms snails, worms, plants, insects
Members of Ecosystems are Related Community - all the populations of organisms living in a given area. Ecosystems rarely function independently of one another because they are connected by both living and non living features.
Ecological Succession Ecological succession - an existing community of organisms is replaced by a different community over time. Can occur where no living community existed before (like a volcano arising from the sea). Can also occur following a dramatic change (like a forest fire). Succession leads to a collection of organisms called a climax community.
Biomes Biome - an environment that has a characteristic climax community. Terrestrial- associated with a land environment 1) a. 2) a. b. 3) 4) a. b. 5) 6) Tropical Rain Forest Grassland Tropical Grassland Temperate Grassland Desert Temperate Deciduous Forest Temperate Rain Forest Taiga Tundra Aquatic- associated with a water environment Freshwater- (rivers, streams, ponds, lakes, wetlands) Estuaries Marine (intertidal zone, coastal ocean, open ocean)
Habitat- an area that provides an organisms with its basic needs for survival Endemic species- a species found in its originating location and is generally restricted to that geographic area Non-native species – species introduced into an area outside of their rang by accidental or deliberate human activity -can also be called: introduced, invasive, alien, nonindigenous, or exotic
Energy flow through ecosystems Of all the sun’s energy the reaches the Earth’s surface, only about 0. 1% is used by living things. Energy cannot be recycled or used again! For this reason, we refer to the movement of energy through an ecosystem as a flow, not a cycle. Biochemical conversion- the changing of organic matter into other chemical forms such as fuels Bioenergetics- the study of energy flow (energy transformations) into and within a living system
Energy flows through ecosystems The sun is the ultimate source of energy for living things. Producers - organisms that make their own food via photosynthesis. Consumers - organisms that get their energy directly or indirectly from producers. Primary consumers - also called herbivores; plant eating animals. Secondary consumers - animals that eat primary consumers.
Energy flows through ecosystems Trophic level - each step in a series of organisms eating other organisms. At each higher trophic level, less and less of the energy originally captured by the producers is available. This is because the energy obtained from digested food is used to maintain metabolism. Only about 10% of the energy from one trophic level can be used by the animals at the next trophic level!
Energy Flows Through Ecosystems Herbivores - organisms that eat only plants. Carnivores - organisms that eat only animals. Omnivores - organisms that eat plants and animals. Decomposers - organisms that obtain energy from nonliving organic matter Energy Pyramid
Ecosystem relationships Food chain simplest feeding relationship linking animals and plants in the biosphere. Usually contains 3 -5 total organisms.
Ecosystem relationships Food web - complex relationship formed by interconnecting and overlapping food chains.
Biotic Interactions in an Ecosystem Competition- finite amount of resources to compete over Predation- one species uses another as food Symbiosis-a close and usually obligatory association of two organisms of different species that live together, often to their mutual benefit Commensalism –one organism benefits without affecting the other Parasitism –one organism benefits (the parasite), at the expense of the other (host) Mutualism – each organism benefits
Nutrients are recycled through an ecosystem nutrients are recycled and used again and again. Biogeochemical cycle - nutrients use these processes to move through the biosphere. Ex. Water, carbon, nitrogen, oxygen cycles
Nutrients are Recycled Through an Ecosystem - Water Cycle Water cycle - movement of water between the atmosphere and Earth. Consists of alternating cycles of evaporation and condensation. Evaporation moves water molecules into the air while precipitation returns it to Earth. Some water sinks into the ground (groundwater) while some runs along the surface of the ground until it enters a river or stream.
Nutrients are Recycled Through an Ecosystem – Carbon Cycle Carbon- required for all organic compounds Carbon Cyclemovement of Carbon through the biosphere
Nutrients are Recycled Through an Ecosystem –Oxygen Cycle - movement of Oxygen through the biosphere
Nutrients are Recycled Through an Ecosystem - Nitrogen Cycle Nitrogen - element required by living organisms to build proteins. Nitrogen cycle - movement of nitrogen through biosphere. Most can’t be used directly by living organisms it must be converted into more usable forms.
Nutrient limitation The rate at which producers can capture energy is limited by the amount of available nutrients. Limiting factor - the nutrient that is in short supply that limits an organism’s growth.