1. Ecology
Ch. 3 and 4

2. Ecology
The interaction between organisms and their environment.

3. Levels of Organization
Biosphere- All life on Earth
Biome- All ecosystems in the same climate
Ecosystem- different groups of organisms plus their environment
Community- different populations that live together
Population- all members of the same species that live together
Individual- a single organism

4. Levels of Organization

5. Energy Flow
The main source of energy for life on Earth is the Sun. That energy is used by producers at the base of the food chain. Consumers then eat the producers and the energy is passed along.

6. Energy Flow
Producers, also called autotrophs. Make carbohydrates from inorganic substances in two different ways:
Photosynthesis -produces energy from sunlight.
Ex.) Plants
Chemosynthesis -produces energy from chemicals.
Ex.) Some types of bacteria

7. Energy Flow
Consumers, also called heterotrophs. Rely on other organisms for food.
Herbivores eat plants
Ex.) Deer
Omnivores eat both plants and animals
Ex.) Humans/bears
Carnivores eat animals
Ex.) Lions/wolves
Detritivores eat dead matter
Ex.) Earthworms
Decomposers break down decaying matter
Ex.) Bacteria/fungi

8. Food Web

9. Energy Flow
Each successive step in a food chain or web is called a trophic level. Energy exchange between each trophic level is considered to be inefficient. This is because only about 10% of energy is stored within the tissues of an organism and passed along to a consumer.
The remaining energy is used for growth, metabolism, respiration reproduction, and some is lost as heat.

10. Energy Pyramids
Pyramid by biomass- shows the amount of living tissue in each level.
Pyramid by numbers- shows the number of organisms in each level.
Examples: Trees in a forest might have a high biomass, but relatively low numbers. Algae in a pond might have a low biomass, but high numbers of individuals.

11. Energy Pyramid

12. Water Cycle
Water Cycle- required for life processes.
Enters the atmosphere through evaporation and transpiration.
Leaves the atmosphere through precipitation.
Cycles through organisms, run-off, ground water and plant roots.

13. Water Cycle

14. Carbon Cycle
Carbon Cycle- key ingredient in making living tissues; also needed for photosynthesis and respiration.
Enters the atmosphere through respiration, volcanic activity and burning.
Leaves the atmosphere through photosynthesis.
Cycles through erosion, feeding, and decomposition.

15. Carbon Cycle

16. Nitrogen Cycle
Nitrogen Cycle- required for making amino acids and building proteins.
Enters the atmosphere through denitrification. This is when bacteria break down nitrates and nitrites into nitrogen gas.
Cycles through nitrogen fixation. This is when bacteria break down ammonia into nitrates and nitrites. Much of this type of bacteria is found on the roots of legumes, or bean plants.
Ammonia is a by-product of animal waste and decay. Human use of fertilizers also distributes nitrogen.

17. Nitrogen Cycle

18. Phosphorus Cycle Does not cycle through the atmosphere.
Phosphorus Cycle- used to build DNA and RNA molecules.
Does not cycle through the atmosphere.
Cycles between organisms and the soil through plants.

19. Limiting Productivity
A single nutrient that can control the numbers of producers in an area, or primary productivity, is called a limiting nutrient.
Algal blooms can form as a result of fertilizer run-off which may suddenly increase the algae’s limiting nutrients.
If there are not enough consumers in an area to eat the algae, this can disrupt the balance of an ecosystem.

20. Interactions Among Organisms
Competition- animals compete, for food, territory, or mates.
Predation-one animal hunts and kills another for food.
Symbiosis -animals use each other for various purposes.

21. Types of Symbiosis Mutualism: both benefit
Ex.) Flowers and insects, birds and cows
Commensalism: one benefits while another is unaffected
Ex.) Lions and hyenas
Parasitism: one benefits while another is harmed
Ex.) Tapeworms and dogs

22. Types of Symbiosis

23. Living influences of an ecosystem
Biotic Factors
Living influences of an ecosystem
Includes: all organisms (plants, animals, fungi…even germs!)

24. Non-living influences of an ecosystem
Abiotic Factors
Non-living influences of an ecosystem
Includes: air, water, temperature, sunlight and minerals

25. Parts of an Ecosystem

26. Populations and Humans in the Biosphere
Ecology Chapters 5 and 6
Populations
and Humans in the Biosphere

27. Population Growth Birth rate = # of individuals born
Death/Mortality rate = # of individuals who die
Population growth = birthrate - death rate

28. Exponential Growth Occurs when populations are growing
Results in a J-shaped graph
Cannot happen forever, because resources eventually run out

29. Logistic Growth
Occurs when population growth slows or stops as a result of limited resources
Produces an S-shaped graph
The number of individuals that can be supported by the environment is called the carrying capacity

30. Limiting Factors
Factors that cause a population’s growth to slow or stop.
May depend on the number of organisms in an area (density-dependent) or may occur regardless of population size (density-independent)

31. Limiting Factors Competition Predation Parasitism Disease Weather
Density-dependent
Density-independent
Competition
Predation
Parasitism
Disease
Weather
Seasons
Natural disasters
Human activity

32. Human Populations Shown using age-structure diagrams
Rapid growth countries have wide base (lots of younger people)
Stable populations have fairly equal categories

33. Age Structure Diagrams