1. 18.1 Ecosystems
What are ecosystems made of?
Our Biosphere

2. Learning Targets
Discuss the importance of chemical and physical factors to living organisms
Describe the role of different species in an ecosystem
Describe the function of an ecosystem, and how different species fill different roles in different ecosystems
Describe energy transfer from the lowest to the highest trophic level in a chain, including energy loss at every trophic level.
Discuss how materials are cycled between trophic levels and how they can enter or leave a food web at any time.

3. Ecosystems Living organisms and nonliving things
Energy moves in ONE direction
Nutrients cycle – Carbon and Nitrogen Cycles
Biotic factors
Living things: Organisms
Abiotic factors – Physical & Chemical Features
Non-living things: Climate, water, sunlight
Abiotic factors include resources living organisms need like light, oxygen, water. Also include environmental features that are not materials or living things, like living space and the right temperature range.

4. Biotic Factors
Species – Single type of organism that can interbreed and produce fertile offspring
Population
Same species, same place, same time
Community
Group of populations
Ecosystem
Communities and abiotic factors
Biosphere

6. Ecological Roles Habitat - Where an organism lives
Ant  Ant hill
Characteristics include climate, weather, food, water
Niche – How organism makes a living
How an organism gets its energy to live and reproduce
Every species fills a niche
Individual organism must acquire enough food energy to live and hopefully reproduce. A species’ way of making a living is called its niche.
Top carnivore niche filled by lions on the savanna, wolves in the tundra, tuna in the oceans

7. Ecological Roles
Biomes – Climate conditions determine which ecosystems are found in which location
Particular biome encompasses all of the ecosystems that have similar climate and organisms.

8. Ecological Roles Producers Consumers
Two ways organisms produce energy: photosynthesize or chemosynthesis
Plants, algae, phytoplankton, bacteria at hydrothermal vents
Consumers
Use food energy created by producers
Herbivores, Carnivores, Omnivores
Herbivores – animals that break down the plant structures to get energy
Carnivores – eat herbivores or other carnivores
Omnivores – eat plants and animals
What role do producers and consumers have on an ecosystem?

9. Ecological Roles
EVERY ecosystem has the SAME general roles that living creatures fill.
It’s just the organisms that fill those niches that are different.
For example, every ecosystem must have some organisms that produce food in the form of chemical energy
What are those roles? Producers, Consumers, decomposers

10. Law of Conservation of Energy
Energy cannot be created or destroyed.
Energy can only be changed from one form to another.

11. Ecological Energy Transfer
Energy moves as one organisms eats another
90% of energy is lost as heat or movement
10% moves on to the next level
Total energy always stays the same
Trophic Levels – Position organism occupies in a food chain

12. Ecological Energy Transfer
Food chains - set of organisms that pass energy from one trophic level to the next
Food webs - A food web recognizes that many organisms eat at multiple trophic levels. A food web includes the relationships between producers, consumers and decomposers.
Food chain – organisms eat at only one trophic level
Why do you think

13. Energy flows through an ecosystem in only one direction
Energy flows through an ecosystem in only one direction. Energy enters the ecosystem with the producers.
Producers are always the first trophic level, herbivores the second, the carnivores that eat herbivores the third, and so on.

14. How come there are not any more higher trophic levels 5 or 6 more
How come there are not any more higher trophic levels 5 or 6 more? There would be no energy left to reach a 6-7th trophic level.
Food chains of ocean animals are longer than land-based because ocean conditions are more stable

15. Why do you think producers and primary consumers have such a small range to hunt or find food for energy, and top predators have a very large range to hunt such as lions in the savanna? Cows can eat just grass because they are extracting the most energy – 10% rule. Humans, we eat a variety of food, because we are getting the least amount of energy compared to producers, primary and secondary consumers.
Why do organisms at higher trophic levels tend to be larger than those at lower levels? A large fish must be able to eat a small fish, but the small fish does not have to be able to eat the large fish.

16. Food web recognizes that many organisms eat at multiple trophic levels.
All organisms depend on two global food webs: Phytoplankton and land plants
Both global food webs are connected: Bears eat berries on land plants and fish in streams. Fish’s source of energy ultimately comes from phytoplankton

17. Nutrient Transfer
Nutrients move from organism to organism – needed for growth
May be a source of competition
Nutrients cycle – Carbon and Nitrogen
Usually not lost; just stored
Not like energy flow only in one direction
Enter and leave an ecosystem at any trophic level.
Unlike energy, there are many ways nutrients can enter into and out of the ecosystem.
Decomposers complete the process of breaking down dead organisms. They convert dead organisms into nutrients and carbon dioxide, which they respire into the air. These left over nutrients are then available for other organisms to use.
When we talk about nutrients, we are talking about carbon. If you eat anything, meat or vegetables, you are taking in carbon. What do you think protein, carbohydrates, and fats are made of?

18. Feeding Relationships
A predator is an animal that kills and eats another animal. The animal it kills is its prey.
Scavengers are animals that eat organisms that are already dead.
Decomposers break apart dead organisms or the waste material of living organisms, returning the nutrients to the ecosystem
Vultures and hyenas are just two types of scavengers.
Many decomposers are bacteria, but there are others as well, including fungi. Decomposers are recyclers; they make nutrients from dead organisms available for living organisms.

19. Relationships Between Species
Competition
More than one population in same niche
Each niche can only be inhabited by one species.
Symbiosis
Living together
Mutualism: good for both (+, +)
Commensalism: good for one (+, 0)
Parasitism: good for one, bad for one (+, -)
Mutualism – plant-pollinator

20. mutualism

21. commensalism

22. parasitism