Ecology

1. Ecology

2. What is Ecology? • Ecologyis 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.

3. 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 factors- physical features • Ex. elevation, humidity, rainfall • (SWATS: soil, water, air, temp, sunlight) • Biotic factors - living organisms • Ex. snails, worms, plants, insects

4. 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.

5. 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.

6. Biomes • Biome- an environment that has a characteristic climax community. • Terrestrial- associated with a land environment • Tropical • Tropical Rain Forest • Grassland • Tropical Grassland • Temperate Grassland • Desert • Temperate • 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)

7. 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

8. 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

9. 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.

10. 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!

11. 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 non-living organic matter Energy Pyramid

12. Ecosystem relationships • Food chain- simplest feeding relationship linking animals and plants in the biosphere. • Usually contains 3-5 total organisms.

13. Ecosystem relationships • Food web- complex relationship formed by interconnecting and overlapping food chains.

14. 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

15. 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

16. 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.

18. Nutrients are Recycled Through an Ecosystem – Carbon Cycle • Carbon- required for all organic compounds • Carbon Cycle- movement of Carbon through the biosphere

19. Nutrients are Recycled Through an Ecosystem –Oxygen Cycle Oxygen Cycle- movement of Oxygen through the biosphere

20. 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.

22. 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.