1. Chapter 3
Ecosystems

2. Make a list of all the living thing and the non living things.
Ecology - study of interactions among and between organisms and their environment.
Make a list of all the living thing and the non living things.

3. Factors that influence an ecosystem
A biotic factor - LIVING part of the ecosystem: animals, plants, mushrooms, bacteria.
An abiotic factor - NONLIVING part: sunlight, heat, precipitation, wind/ water currents, soil type, etc.

4. Levels of Organization
Biosphere—our entire planet.
Biome—a group of ecosystems that share similar climates and typical organisms
Ecosystem—all the organisms that live in a place, together with their physical environment
Individual organism – ONE moose.
Population— TWO or MORE moose.
Community— moose AND rabbits AND hawks.

5. Food Chains Food chains can vary in length as shown below
A food chain is a series of steps in which organisms transfer energy by eating and being eaten.
Food chains can vary in length as shown below

6. Primary Producers Consumers Make their own food.
Ex. Autotrophs – plants, algae do photosynthesis; some bacteria do chemosynthesis
Consumers
eat other organisms.
Ex. Heterotrophs - ingesting organisms somehow

7. Types of Consumers
Carnivores - kill and eat other animals
Herbivores - eat plant leaves, roots, seeds, or fruits.
Omnivores – eat both plants and animals.
Decomposers/detritivore - break down dead organic matter. (mushrooms, earth worms, some bacteria)

8. Decomposers and Detritivores in Food Webs
decomposers convert dead material to detritus, which is eaten by detritivores, such as crayfish, grass shrimp, and worms.
Pig frogs, killifish, and other fishes eat the detritivores.
The decomposition process releases nutrients that can be used by primary producers  recycling
Without decomposers, nutrients would remain locked in dead organisms.

9. Food Webs Each path through a food web is a food chain.
In most ecosystems, feeding relationships are much more complicated than the relationships described in a single, simple chain because many animals eat more than one kind of food.
Each path through a food web is a food chain.

10. Food Webs and Disturbance
In recent years, krill populations have dropped substantially.
Given the structure of this food web, What would happen to the other members of the food web shown?

11. Trophic Levels
Each step in a food chain or food web is called a trophic level.
Primary producers always make up the first trophic level.

12. Pyramids of Energy Remaining energy is released as heat.
Organisms use energy they acquire on life processes like respiration, growth, reproduction. (90%)
Remaining energy is released as heat.
about 10% is available to transfer to the next trophic level.

13. Pyramids of Biomass and Numbers
Total amount of living tissue within a given trophic level biomass.
Pyramid of biomass relative amount of living organic matter at each trophic level- greatest biomass base
Pyramid of numbers relative number of individual organisms at each trophic level in an ecosystem.

14. Pyramids of Biomass and Numbers
In some cases, however, consumers are much smaller than organisms they feed upon.
Thousands of insects may graze on a single tree, for example. The tree has a lot of biomass, but represents only one organism.
In such cases, the pyramid of numbers may be turned upside down, but the pyramid of biomass usually still has the normal orientation.

15. Recycling in the Biosphere
Unlike the flow of energy (food chain), matter is recycled within ecosystems.
Atoms are passed from organisms to other parts of the biosphere through biogeochemical cycles, powered by the flow of energy.
As matter moves through these cycles, it is never created or destroyed—just changed.

16. Human Activity mining and burning of fossil fuels
Human activities that affect cycles of matter on a global scale include:
mining and burning of fossil fuels
clearing of land for building and farming
burning of forests
manufacture and use of fertilizers

17. The Water Cycle
Water continuously moves between the oceans, the atmosphere, and land—sometimes outside living organisms and sometimes inside them.

18. Nutrient Cycles
Oxygen participates in parts of the carbon, nitrogen, and phosphorus cycles by combining with these elements and cycling with them through parts of their journeys.
Oxygen gas in the atmosphere is released by one of the most important of all biological activities: ?????
Oxygen is used in respiration by all multicellular forms of life, and many single-celled organisms as well.

19. The Carbon Cycle
Carbon is a major component of all organic compounds, including c___________, l________, p_________, and n_______ a______. 

20. The Nitrogen Cycle
All organisms require nitrogen to make amino acids, which are used to build ___________ and nucleic acids, which combine to form DNA and RNA.
Nitrogen gas (N2) makes up 78 percent of Earth’s atmosphere.

21. The Nitrogen Cycle
Certain bacteria convert nitrogen gas into ammonia, in a process known as nitrogen fixation.
Other soil bacteria convert fixed nitrogen into nitrates and nitrites that primary producers can use to make proteins and nucleic acids.
Yet other bacteria convert nitrates into nitrogen gas  denitrification.

22. The Phosphorus Cycle
Phosphorus forms a part of vital molecules such as DNA and RNA.
Although phosphorus is of great biological importance, it is not abundant in the biosphere.
Plants bind phosphate into organic compounds when they absorb it from soil or water.

23. Nutrient Limitation
Most fertilizers contain large amounts of nitrogen, phosphorus, and potassium, which help plants grow better in poor soil.
Runoff with excess fertilizers can cause an algal bloom—a dramatic increase in the amount of algae and other primary producers due to the increase in nutrients.