1. Chapter 13: Ecology

2. 13.1 Ecologists Study Relationships
KEY CONCEPT Ecology - is the study of the relationships among organisms and their environment.

3. Ecologists study environments at different levels of organization.
13.1 Ecologists Study Relationships
Ecologists study environments at different levels of organization.

4. An organism is an individual living thing, such as an alligator.
13.1 Ecologists Study Relationships
An organism is an individual living thing, such as an alligator.
Organism

5. A population is a group of the same species that lives in one area.
13.1 Ecologists Study Relationships
A population is a group of the same species that lives in one area.
Population
Organism

6. 13.1 Ecologists Study Relationships
A community is a group of different species (populations) that live together in one area.
Community
Population
Organism

7. 13.1 Ecologists Study Relationships
An ecosystem includes all of the organisms as well as the climate, soil, water, rocks and other nonliving things in a given area.
Ecosystem
Ecosystem
Community
Population
Organism

8. Biome
13.1 Ecologists Study Relationships
A biome is a major regional or global community of organisms characterized by the climate conditions and plant communities that thrive there.
Ecosystem
Community
Population
Organism

9. 13.2 Biotic & Abiotic Factors
KEY CONCEPT Every ecosystem includes both living and nonliving factors.

10. Biotic factors are living things. plants animals fungi bacteria
13.2 Biotic & Abiotic Factors
Biotic factors are living things.
plants
animals
fungi
bacteria
plants

11. Abiotic factors are nonliving things.
13.2 Biotic & Abiotic Factors
Abiotic factors are nonliving things.
moisture
temperature
wind
sunlight
Soil
Water
Rocks
moisture
sunlight

12. Changing one factor in an ecosystem can affect many other factors.
13.2 Biotic & Abiotic Factors
Changing one factor in an ecosystem can affect many other factors.
Biodiversity is the assortment, or variety, of living things in an ecosystem.
Rain forests have more biodiversity than other locations in the world.

13. 13.2 Biotic & Abiotic Factors
A keystone species is a species that has an unusually large effect on its ecosystem.
keystone

14. Keystone species form and maintain a complex web of life.
13.2 Biotic & Abiotic Factors
Keystone species form and maintain a complex web of life.
creation of
wetland
ecosystem
increased waterfowl
Population
increased fish
population
nesting sites for birds
keystone species

15. KEY CONCEPT Life in an ecosystem requires a source of energy.
13.3 Energy in Ecosystems
KEY CONCEPT Life in an ecosystem requires a source of energy.

16. Producers provide energy for other organisms in an ecosystem.
13.3 Energy in Ecosystems
Producers provide energy for other organisms in an ecosystem.
Producers get their energy from non-living resources. (The SUN)
Producers are also called autotrophs because they make their own food.
Plants

17. carbon dioxide + water + hydrogen sulfide + oxygen
13.3 Energy in Ecosystems
Photosynthesis = producers use sunlight as an energy source.
carbon dioxide + water +
hydrogen sulfide + oxygen
sugar + sulfuric acid

18. Also called heterotrophs … they feed off of different things.
13.3 Energy in Ecosystems
Consumers
organisms that get their energy by eating other living or once-living resources.
Also called heterotrophs … they feed off of different things.

19. 13.4 Food Chains & Webs
KEY CONCEPT Food chains and food webs model the flow of energy in an ecosystem.

20. 13.4 Food Chains & Webs
A food chain follows the connection between one producer & a single chain of consumers within an ecosystem.
DESERT COTTONTAIL
GRAMA GRASS
HARRIS’S HAWK

21. Consumers are not all alike.
13.4 Food Chains & Webs
Consumers are not all alike.
Herbivores eat only plants.
Carnivores eat only animals.
Omnivores eat both plants and animals.
Detritivores eat dead organic matter.
Decomposers are detritivores that break down organic matter into simpler compounds.
carnivore
decomposer
Herbivore

22. Trophic levels are the nourishment levels in a food chain.
13.4 Food Chains & Webs
Trophic levels are the nourishment levels in a food chain.
Primary consumers are herbivores that eat producers.
Secondary consumers are carnivores that eat herbivores.
Tertiary consumers are carnivores that eat secondary consumers.

23. 13.4 Food Chains & Webs
A food web emphasizes complicated feeding relationships & energy flow in an ecosystem.

24. 13.4 Food Chains & Webs

25. Energy Flows through an Ecosystem and Nutrients Cycle in an Ecosystem.
13.5 Nutrient Cycles
Energy Flows through an Ecosystem and Nutrients Cycle in an Ecosystem.
2. the Primary Nutrient Cycles:     A. The Water Cycle        B. The Nitrogen Cycle

26. Water is crucial to Life. Cells contain 70 to 90 percent water.
13.5 Nutrient Cycles
THE WATER CYCLE
Water is crucial to Life.
Cells contain 70 to 90 percent water.
most of Life’s reactions occur in water.

27. Water is found in 3 Reservoirs
13.5 Nutrient Cycles
Water is found in 3 Reservoirs
Bodies of Water (Lakes, Rivers, Streams, & Oceans)
Atmosphere (in the form of Water Vapor.)
Underground (“Ground Water”)
The Movement of Water between these different reservoirs is known as the Water Cycle.

28. The Water Cycle Usually Consists of the following steps: EVAPORATION
13.5 Nutrient Cycles
The Water Cycle Usually Consists of the following steps:
EVAPORATION
TRANSPIRATION
CONDENSATION
PRECIPITATION
RUN OFF (or RETURN)

29. EVAPORATION from lakes, rivers, and oceans.
13.5 Nutrient Cycles
EVAPORATION from lakes, rivers, and oceans. 

30. TRANSPIRATION from plants and trees.
13.5 Nutrient Cycles
TRANSPIRATION from plants and trees.

31. CONDENSATION – Cloud Formation
13.5 Nutrient Cycles
CONDENSATION – Cloud Formation

32. PRECIPITATION – Rain, Snow, Sleet, Hail.
13.5 Nutrient Cycles
PRECIPITATION – Rain, Snow, Sleet, Hail.

33. RUN OFF, or RETURNED back into the Cycle.
13.5 Nutrient Cycles
RUN OFF, or RETURNED back into the Cycle.

35. 13.5 Nutrient Cycles
THE NITROGEN CYCLE
ALL Organisms need Nitrogen, to make Proteins and Nucleic Acids. (DNA & RNA)
Most Nitrogen is found in the Atmosphere and most living things can’t use it.
ALL Organisms rely on Bacteria to change Nitrogen Gas into a Usable Form.

36. 13.5 Nutrient Cycles
Conversion of Nitrogen Gas to Ammonia by bacteria is called Nitrogen Fixation.
Bacteria live in the soil and in the roots of some kinds of plants, such as beans, peas, clover, and alfalfa.
They have Enzymes that can break the atmospheric N2 bonds and form Ammonia (NH3).

37. Nitrogen Cycle

38. Then consumers obtain nitrogen from eating plants and animals.
13.5 Nutrient Cycles
Ammonia can be absorbed by plants from the soil, and used to make proteins
Then consumers obtain nitrogen from eating plants and animals.

39. Decomposers return Nitrogen back to the soil…
13.5 Nutrient Cycles
Decomposers return Nitrogen back to the soil…
from the remains of dead plants and animals. 
from animal waste (dung & urine)
This process is known as AMMONIFICATION.

40. 13.5 Nutrient Cycles
DENITRIFICATION is when Bacteria break down Nitrates and release Nitrogen Gas back into the Atmosphere.

41. 13.5 Nutrient Cycles
In Conclusion: Plants DEPEND on nitrogen fixing bacteria, and all other organisms including YOU, DEPEND ON THEM!

42. 13.6 Pyramid Models
KEY CONCEPT Pyramids model the distribution of energy and matter in an ecosystem.

43. 13.6 Pyramid Models
Energy pyramids compare energy used by producers and other organisms on different levels called trophic levels.
Between each level of an energy pyramid, up to 90% of the energy is lost into the atmosphere as HEAT.
Only 10% of the energy at each tier is transferred from one trophic level to the next.
energy
lost
energy transferred

44. 13.6 Pyramid Models
Biomass Pyramid - is a measure of the total dry mass of organisms in a given area.
tertiary
consumers
secondary
primary
producers
75 g/m2
150g/m2
675g/m2
2000g/m2

45. 13.6 Pyramid Models
A pyramid of numbers shows the numbers of individual organisms at each trophic level in an ecosystem.
A vast number of producers are required to support even a few top level consumers.
tertiary
consumers
secondary
primary
producers 5
5000
500,000
5,000,000