1. Ecology

2. Ecologists study interactions among organisms at different levels
They also study how abiotic (non living) factors (such as land, sun, water) affect organisms
All organisms depend on each other for food, shelter, reproduction, or protection

3. Populations-a group of organisms of one species that interbreed and live in the same place at the same time, they compete with each other for food, shelter, and other resources
A population is made of individuals

4. A community is a collection of interacting populations
A change in one population in a community will cause changes in the other populations

5. An ecosystem is made of the interactions among the populations in a community and the abiotic factors in a community

6. Habitat vs. Niche
A habitat is the place where an organism lives out its life
A niche is the role and position a species has in its environment and how it meets its needs and interacts

7. Relationships between species AKA symbiotic relationships
Predator Prey
Commensalism-one species benefits and the other is not harmed and it does not benefit
Mutualism-both species benefit
Parasitism-one organism benefits at the expense of another

8. How do organisms get their energy?
Ultimately from the sun
Think about it…what did you (the organism) have for breakfast?
Cereal? Comes from grains which get energy from the sun.
Bacon? Comes from a pig which eats plants that get their energy from the sun.

9. Autotrophs-organisms that use energy from the sun or energy stored in chemical compounds to make their own food
Heterotrophs-organims that cannot make their own food

10. Scavengers-do not kill for food, they eat animals that have already dies (some birds, etc..)
Decomposers-break down and absorb nutrients from dead organisms (bacteria, fungi, etc…)

11. How does energy flow in an ecosystem?
Food chains-paths for energy, nutrients go from autotrophs to heterotrophs to decomposers
Food chains are used by drawing arrows that show the way the energy moves (energy is highest at the beginning as it is lost as heat throughout the chain)

13. Each organism in a food chain represents a step in a trophic level (levels away from the sun)
Many species may occupy the same trophic level, so a food web is used to show this

14. Food webs
Food webs-express all the possible feeding relationships at each trophic level in a community

16. Ecological pyramids are also used to model the distribution of energy within an ecosystem
The base of the pyramid is the first trophic level/the autotrophs

18. Higher up trophic levels are layered on top of one another.
The energy that actually makes it up a trophic level varies but is closer to 10%
Why? Energy is lost in getting the food, metabolism, heat, and waste

19. What can an ecosystem be?
A puddle of water to a large forest, but all ecosystems must have the flow of energy and the cycling of chemical elements
They also have structure, living and nonliving parts, processes, and change over time

20. Nested ecosystems-ecosystems that are one inside another
Ecosystems do not always have definable edges, most are blurred. This blurred edge is called an ecotone

21. Biogeochemical cycles
the cycling of chemical elements required by life between the living and nonliving parts of the environment. Some examples of these chemical elements are H2O, P, S, N2, O2 and C.
These elements cycle in either a gas cycle or a sedimentary cycle; some cycle as both a gas and sediment.

22. Biogeochemical cycles
In a gas cycle elements move through the atmosphere. Main reservoirs are the atmosphere and the ocean.
In a sedimentary cycle elements move from land to water to sediment. Main reservoirs are the soil and sedimentary rocks.

23. Biogeochemical cycles
Gas Cycles:                         Sedimentary Cycles:
Carbon                                             Phosphorus Nitrogen                                             Sulfur Oxygen

24. Biogeochemical cycles…carbon
How do living things obtain carbon?
Carbon is extracted from the atmosphere by plants through the process known as photosynthesis. This carbon is combined with other elements in complex ways to form organic molecules important to life.
This carbon is later transferred to animals who consume or eat plants. When plants and animals die, much of their carbon is returned to the atmosphere as the organisms decompose.

25. Biogeochemical cycles…carbon
Every so often, a plant or animal does not decompose right away. Their bodies are trapped, in locations where decomposition can simply not take place. This is most common at the bottom of oceans and seas, where the life forms become buried by sand.
Instead of returning to the atmosphere, the carbon from these life forms is trapped within the Earth. Over millions of years more and more of the carbon on Earth has been trapped in this manner. Today, almost 99% of all the carbon on Earth has been locked up deep within the Earth.

26. Biogeochemical cycles…carbon
As rocks weather, this carbon is slowly released back into the atmosphere, creating a balance. For the past several hundred million years, the amount of carbon being locked up in the Earth, and the amount being released by weathering rocks was almost perfectly balanced

27. Biogeochemical cycles…carbon
This important balance has been altered significantly in the past century, as humans have begun using fossil fuels to produce energy. By burning the Earth’s store of carbon, mankind is able to create the energy needed to operate our communities. However, we must be careful as we do so. By releasing more carbon into the atmosphere than is being locked up, we risk causing damage to the delicate carbon cycle.

29. Biogeochemical cycles…oxygen
Oxygen exists in our modern atmosphere in great amounts. Approximately 21% of the atmosphere is comprised of oxygen. This was not always the case however.
Billions of years ago, it is believed that there was virtually no oxygen found in the atmosphere at all. What caused an increase in oxygen levels?
Most of the oxygen now found in our atmosphere was released by plants, as a bi-product of photosynthesis. Over millions of years, as plants around the globe released oxygen, the levels continued to rise, until they reached a balance around 1 billion years ago.

30. Biogeochemical cycles…oxygen
For the last billion years, the amount of oxygen has remained relatively constant. At the same time that plants continue adding oxygen to the atmosphere, it is also being removed by various processes.
Oxygen is highly reactive. As the oxygen in our atmosphere interacts with other substances, it often bonds to them, becoming trapped. Many life forms also remove oxygen from the atmosphere, as they breath. This oxygen is used by these life forms to carry out the functions of life.

32. Biogeochemical cycles…nitrogen
Nitrogen is the most abundant element in our planet’s atmosphere. Approximately 78% of the atmosphere is comprised of this important element.
Nitrogen is used by life forms to carry out many of the functions of life. This element is especially important to plant life. Yet nitrogen in its gaseous form is almost entirely unusable to life forms. It must first be converted or ‘fixed’ into a more usable form. The process of converting nitrogen is called fixation.

33. Biogeochemical cycles…nitrogen
There are specialized bacteria whose function it is to fix nitrogen, converting it, so that it can be used by plants. There are still other bacteria who do the reverse. That is, they return nitrogen to is gaseous form.
After nitrogen is fixed, it can be absorbed, and used by plants, and subsequently by animals.

34. Biogeochemical cycles…nitrogen
The process of nitrogen being fixed, used by plants and animals, and later returned to the atmosphere is referred to as the nitrogen cycle.

36. The water cycle aka The Hydrologic Cycle
Water is found throughout the biosphere, and is probably the most important substance needed to sustain life forms. Humans can survive for many weeks without the energy obtained by eating food, however, we would only last a few days without water.

37. Biogeochemical cycles…phosphorus
Phosphorus is an essential nutrient for plants and animals in the form of ions PO43- and HPO42-. It is a part of DNA-molecules, of molecules that store energy (ATP and ADP) and of fats of cell membranes. Phosphorus is also a building block of certain parts of the human and animal body, such as the bones and teeth.

38. Biogeochemical cycles…phosphorus
Phosphorus can be found on earth in water, soil and sediments. Unlike the compounds of other matter cycles phosphorus cannot be found in air in the gaseous state. This is because phosphorus is usually liquid at normal temperatures and pressures.

39. Biogeochemical cycles…phosphorus
It is mainly cycling through water, soil and sediments. In the atmosphere phosphorus can mainly be found as very small dust particles. Phosphorus moves slowly from deposits on land and in sediments, to living organisms, and than much more slowly back into the soil and water sediment.

40. Biogeochemical cycles…phosphorus
Phosphorus is most commonly found in rock formations and ocean sediments as phosphate salts. Phosphate salts that are released from rocks through weathering usually dissolve in soil water and will be absorbed by plants. Because the quantities of phosphorus in soil are generally small, it is often the limiting factor for plant growth. That is why humans often apply phosphate fertilizers on farmland.

41. Biogeochemical cycles…phosphorus
Phosphates are also limiting factors for plant-growth in marine ecosystems, because they are not very water-soluble. Animals absorb phosphates by eating plants or plant-eating animals. Phosphorus cycles through plants and animals much faster than it does through rocks and sediments.

42. Biogeochemical cycles…phosphorus
When animals and plants die, phosphates will return to the soils or oceans again during decay. After that, phosphorus will end up in sediments or rock formations again, remaining there for millions of years. Eventually, phosphorus is released again through weathering and the cycle starts over.

45. Biogeochemical cycles…sulfur
Sulfur is one of the components that make up proteins and vitamins. Proteins consist of amino acids that contain sulfur atoms. Sulfur is important for the functioning of proteins and enzymes in plants, and in animals that depend upon plants for sulfur. Plants absorb sulfur when it is dissolved in water. Animals consume these plants, so that they take up enough sulfur to maintain their health.

46. Biogeochemical cycles…sulfur
Most of the earth's sulfur is tied up in rocks and salts or buried deep in the ocean in oceanic sediments. Sulfur can also be found in the atmosphere. It enters the atmosphere through both natural and human sources. Natural recourses can be for instance volcanic eruptions, bacterial processes, evaporation from water, or decaying organisms.

47. Biogeochemical cycles…sulfur
When sulfur enters the atmosphere through human activity, this is mainly a consequence of industrial processes where sulfur dioxide (SO2) and hydrogen sulphide (H2S) gases are emitted on a wide scale. When sulfur dioxide enters the atmosphere it will react with oxygen to produce sulfur trioxide gas (SO3), or with other chemicals in the atmosphere, to produce sulfur salts.

48. Biogeochemical cycles…sulfur
Sulfur dioxide may also react with water to produce sulphuric acid (H2SO4). Sulphuric acid may also be produced from demethylsulphide, which is emitted to the atmosphere by plankton species. All these particles will settle back onto earth, or react with rain and fall back onto earth as acid deposition. The particles will than be absorbed by plants again and are released back into the atmosphere, so that the sulfur cycle will start over again.

51. The water cycle aka The Hydrologic Cycle
Water is used to carry out the many important, and complex chemical reactions that all life forms must perform in order to survive. Water carries nutrients to various parts of a life form, and carries waste away from the different parts of a life form. Because water is so important, the most abundant substance in any organism is water.

52. The water cycle aka The Hydrologic Cycle
The water found within your body as you read this article has been used, and re-used by organisms throughout the history of Earth. It is quite possible that there is water found in your body, that was once inside of a tyrannosaurus rex, or inside of Julius Caesar.
The process of water moving through the environment is referred to as the hydrologic cycle.