1. 1
Ecology
Ecology is the study of the interactions among organisms and their environment.
Ecologists are scientists who study these relationships.

2. 1
Ecology
Ecologists organize the environmental factors that influence organisms into two groups—nonliving and living or once-living.
Abiotic (ay bi AH tihk) factors are the non-living parts of the environment.
Living or once-living organisms in the environment are called biotic (bi AH tihk) factors.

3. 1
Abiotic Factors
In any environment, birds, insects, and other living things, including humans, depend on one another for food and shelter.
They also depend on the abiotic factors that surround them, such as water, sunlight, temperature, air, and soil.

4. Water 1 All living organisms need water to survive.
Water is an important part of the cytoplasm in cells and the fluid that surrounds cells.
Respiration, photosynthesis, digestion, and other important life processes can only occur in the presence of water.

5. 1
Water
Salt water accounts for 97 percent of the water on Earth. It is found in the seas and oceans.

6. 1
Light and Temperature
The availability of sunlight is a major factor in determining where green plants and other photosynthetic organisms live.
By the process of photosynthesis, energy from the Sun is changed into chemical energy that is used for life process.

7. 1
Light and Temperature
Some areas of the world have a fairly consistent temperature year round, but other areas have seasons during which temperatures vary.
Water environments throughout the world also have widely varied temperatures.

8. 1
Air
Air is composed of a mixture of gases including nitrogen, oxygen, and carbon dioxide.
Most plants and animals depend on the gases in air for respiration.
Polluted air can cause the species in an area to change, move, or die off.

9. 1
Air
Clouds and weather occur in the bottom 8 km to 16 km of the atmosphere.
All species are affected by the weather in the area where they live.
Higher altitudes have less air pressure. Few organisms live at extreme air pressures.

10. 1
Soil
Soil type is determined by the amount of sand, silt, and clay it contains.
Click image to view movie.

11. Soil 1 Different plants need different kinds of soil.
Because the types of plants in an area help determine which other organisms can survive in that area, soil affects every organism in an environment.

12. 1
Biotic Factors
Organisms depend on other organisms for food, shelter, protection, and reproduction.
How organisms interact with one another and with abiotic factors can be described in an organized way.

13. Levels of Organization1
Levels of Organization
The living world is organized in levels.
An organism is one individual from a population.

14. Levels of Organization1
Levels of Organization
All of the individuals of one species that live in the same area at the same time make up a population.

15. Levels of Organization1
Levels of Organization
The populations of different species that interact in some way are called a community.

16. Levels of Organization1
Levels of Organization
All of the communities in an area and the abiotic factors they interact with make up an ecosystem.

17. Levels of Organization1
Levels of Organization
A biome is a large region with plants and animals well adapted to the soil and climate of the region.

18. Levels of Organization1
Levels of Organization
The level of biological organization that is made up of all the ecosystems on Earth is the biosphere.

19. Levels of Organization1
Levels of Organization
The biosphere includes the top part of Earth’s crust, all the waters that cover Earth’s surface, the surrounding atmosphere, and all biomes.

20. Characteristics of Population—Population Size2
Characteristics of Population—Population Size
The number of individuals in the population is the population’s size.
If a population is small and made up of organisms that do not move, the size can be determined by counting the individuals.
Usually individuals are too widespread or move around too much to be counted. The population size then is estimated.

21. 2
Population Size
Using the data table, create a double bar graph showing alligator births and deaths for four years.

22. 2
Population Size
The size of a population is always changing. The rate of change in population size varies from population to
population.
The size of human population is increasing each year.

23. 2
Population Size
In year ____, the rabbit population reached its highest point.
What was the size of the rabbit population in that year?
How do you think the rabbit population affected the fox population over the same ten year period?

24. Population Size 2 Predator-Prey Interactions
On Isle Royale, an island in Lake Superior, the populations of wolves (the predator) and moose (the prey) rise and fall in cycles.

25. 2
Population Density
The number of individuals in a population that occupy a definite area is called population density.
When more individuals live in a given amount of space the population is more dense.

26. 2
Population Density
Population density is the number of individuals in an area of a specific size.
Population density = # of individuals / unit area
In the pond on the top, there are 10 flamingos in 8 square meters.
The population density is 1.25 flamingos per square meter.
What is the population density of the flamingos in the pond on the bottom?

27. 2
Population Spacing
Another characteristic of populations is spacing, or how the organisms are arranged in a given area.
They can be evenly spaced, randomly spaced, or clumped together.

28. 2
Limiting Factors
All ecosystems have a limited amount of food, water, living space, mates, nesting sites, and other resources.
A limiting factor is any biotic or abiotic factor that limits the number of individuals in a population.

29. 2
Limiting Factors
Competition is the struggle among organisms to obtain the same resources needed to survive and reproduce.
As population density increases, so does competition among individuals for the resources in their environment.

30. 2
Carrying Capacity
Carrying capacity is the largest number of individuals of a species that an environment can support and maintain for a long period of time.
If a population gets bigger than the carrying capacity of the environment, some individuals are left without adequate resources.

31. 2
Biotic Potential
The maximum rate at which a population increases when plenty of food and water are available, the weather is ideal, and no diseases or enemies exist, is its biotic potential.
Most populations never reach their biotic potential, or they do so for only a short period of time.
Eventually, the carrying capacity of the environment is reached and the population stops increasing.

32. Symbiosis – Close interaction between species
Mutualism – When both species benefit from the relationship
Commensalism – a form of symbiosis that helps one species but has not effect on the other.
Examples – Moss growing on trees, cattle egrets and livestock

33. Parasitism – When one species is harmed and the other benefits
Examples – Dog and fleas
Predation – when one species hunts, kills and eats another

34. Habitat - Where an organism lives
Niche - an organism's function in its ecosystem

35. Energy – moves through a community as producers and consumers interact Food Chain – How food energy moves from one organism to another Food webs – Overlapping food chains to better show the way energy moves through an ecosystem

36. Ecological Pyramids- bottom layers of pyramid represents ecosystem producers; top layers represent consumers
Energy Pyramids – compares the energy available at each level of a food chain; bottom levels have more energy than the top levels

37. Cycles of Matter – matter that makes up living organisms, such as water, carbon, and nitrogen, are recycled through the environment.
Process of evaporation, condensation, and precipitation make up the water cycle.
Carbon, nitrogen, phosphorus, sulfur, and other elements needed by living organisms move through Earths biosphere

38. 3
The Cycles of Matter
The law of conservation of mass states that matter on Earth is never lost or gained. It is used over and over again.
The carbon atoms in your body might have been on Earth since the planet formed billions of years ago. They have been recycled billions of times.

39. 3
Water Cycle
The water cycle involves the process of evaporation, condensation, and precipitation.
Heat from the Sun causes water on Earth’s surface to evaporate, or change from a liquid to a gas, and rise into the atmosphere as water vapor.

40. 3
Water Cycle
Eventually, the water vapor changes back into tiny droplets of water.
It condenses, or changes from a gas to a liquid.
When the droplets become large and heavy enough, they fall back to Earth as rain or other precipitation.

41. Other Cycles in Nature 3 The movement of carbon through Earth’s
biosphere is called the carbon cycle.

42. 3
Other Cycles in Nature
The nitrogen cycle begins with the transfer of nitrogen from the atmosphere to producers then to consumers.
The nitrogen then moves back to the atmosphere or directly into producers again.
Phosphorus, sulfur, and other elements needed by living organisms also are used and returned to the environment.