1. The Principles of Ecology
Chapter 13

2. Understanding the World
What affects the environment also affects you.
Understanding what affects the environment is important because it is where you live. (ie. Global Warming)

3. What is Ecology?
Ecology is the study of interactions that take place between organisms and their environment
Ecology covers the study of plants and animals, including where they grow and live, what they eat, or what eats them, is called natural history

4. Ecologists study environments at different levels of organization.

5. An organism is an individual living thing, such as an alligator.

6. A population is a group of the same species that lives in one area.
Organism

7. A community is a group of different species that live together in one area.
Population
Organism

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

9. A biome is the portion of the Earth that supports life.
Supports a diverse group of organisms
Biome
Ecosystem
Community
Population
Organism

10. Ecological Research
Most ecologists use scientific research includes using descriptive and quantitative methods
They obtain descriptive information by observing organisms

11. Ecological research methods include observation, experimentation, and modeling.
Observation is the act of carefully watching something over time.
Observations of populations can be done by visual surveys.
Direct surveys for easy to spot species employ binoculars or scopes.
Indirect surveys are used for species that are difficult to track and include looking for other signs of their presence.

12. Experiments are performed in the lab or in the field.
Lab experiments give researchers more control.
Lab experiments are not reflective of the complex interactions in nature.
Field experiments give a more accurate picture of natural interactions.
Field experiments may not help determine actual cause and effect.

13. Computer and mathematical models can be used to describe and model nature.
Modeling allows scientists to learn about organisms or ecosystems in ways that would not be possible in a natural or lab setting.
Ecologists use data transmitted by GPS receivers worn by elephants to develop computer models of the animal’s movements.

14. Biotic vs. Abiotic
The biosphere consist of living & nonliving organisms within the environment
Biotic Factors-all living things that inhabit an environment
Abiotic Factors-non-living things in an environment

15. An ecosystem includes both biotic and abiotic factors.
Biotic factors include:
plants
animals
fungi
bacteria
plants

16. Abiotic factors include:.
Moisture
Temperature
Wind
Sunlight
Soil
Water
moisture
sunlight

17. 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, but are threatened by human activities.

18. Biological Diversity
Biodiversity refers to the variety of species in a specific area
Areas around the world differ in biodiversity.
Biodiversity increases as you move toward the equator

19. Stability to an Ecosystem
Biodiversity can bring stability to an ecosystem.
A pest could easily destroy all the corn in a farmer’s field, but it would be far more difficult for a single type of insect or disease to destroy all individuals of a plant species in a rain forest.

20. Where is Biodiversity found?
Tropical regions contain two-thirds of all land species on Earth
The richest environments for biodiversity all seem to be warm places: tropical rain forests, coral reefs, and large tropical lakes.

21. Studying Biodiversity
How do ecologists perform experiments related to biodiversity?
Researchers catalogue the organisms that live in coral reefs and others attach radio collars to sea turtles.

22. Ecosystems
Populations of plants and animals that interact with each other in a given area and with the abiotic components of that area.
An ecosystem is made up of interacting populations in a biological community and the community’s abiotic factors.

23. 2 Major Types of Ecosystems
Terrestrial Ecosystem: located on land
Aquatic Ecosystem: found in both fresh and salt water

24. Marine Ecosystems
Saltwater ecosystems, also called marine ecosystems, make up approximately 70 percent of Earth’s surface

25. Organisms in Ecosystems
A habitat is the place where an organism lives out its life.
Habitats can change, and even disappear. Habitats can change due to both natural and human causes.

26. Nutrition & Energy Flow

27. The Producers: Autotrophs
The ultimate source of the energy for life is the sun
Plants use the sun’s energy to manufacture food in a process called photosynthesis
An organism that uses light energy or energy stored in chemical compounds to make energy-rich compounds is a producer, or autotroph.

28. Almost all producers obtain energy from sunlight.
Photosynthesis in most producers uses sunlight as an energy source.
Chemosynthesis in prokaryote producers uses chemicals as an energy source.
carbon dioxide + water + hydrogen sulfide + oxygen
sugar + sulfuric acid

29. The Consumer: Heterotrophs
An organism that cannot make its own food and feeds on other organisms is called a Heterotrophs
Heterotrophs include: organisms that feed only on autotrophs, organisms that feed only on other heterotrophs, and organisms that feed on both autotrophs and heterotrophs

30. Herbivores
Herbivores are heterotrophs that feed on only plants

31. Carnivores
Carnivores are heterotrophs that feed on only meat

32. Omnivores
Omnivores are heterotrophs that feed on both plants and animals
badger
American Black Bear

33. Scavengers
Scavengers are heterotrophs that feed on animals that have already died

34. Decomposers
Some organisms, such as bacteria and fungi, are decomposers
Decomposers break down the complex compounds of dead and decaying plants and animals into simpler molecules that can be more easily absorbed

35. Specialists are consumers that primarily eat one specific organism or a very small number of organisms.
Generalists are consumers that have a varying diet.

36. Generalists: The Virginia opossum found across US, feeds on most anything from eggs & dead animals to fruits & plants
Specialists:
The koala of Australia feeds only on the leaves of a few species of eucalyptus trees

37. Flow of Matter and Energy in Ecosystems

38. Food Chain
A simple model that scientists use to show how matter and energy move through an ecosystem
In a food chain, nutrients and energy move from autotrophs to heterotrophs and, eventually, to decomposers
A food chain is drawn using arrows to indicate the direction in which energy is transferred from one organism to the next- uses 3 to 5 links
berries → mice → black bear

39. A food chain links species by their feeding relationships.
A food chain follows the connection between one producer and a single chain of consumers within an ecosystem.
DESERT COTTONTAIL
GRAMA GRASS
HARRIS’S HAWK

40. Trophic Levels
Each organism in a food chain represents a feeding step, or trophic level, in the passage of energy and materials
A food chain represents only one possible route for the transfer of matter and energy through an ecosystem
Measured by the amount of biomass

41. 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.
Omnivores, such as humans that eat both plants and animals, may be listed at different trophic levels in different food chains.

42. A food web shows a complex network of feeding relationships
A food web shows multiple feeding relationships at each trophic level in an ecosystem
A food web emphasizes complicated feeding relationships and energy flow in an ecosystem

43. Ecological Pyramid
An ecological pyramid can show how energy flows through an ecosystem
The base of the ecological pyramid represents the autotrophs, or first trophic level. Higher trophic levels are layered on top of one another.
Energy pyramids compare energy used by producers and other organisms at each trophic levels.

44. energy transferred
energy
lost
Between each tier of an energy pyramid, up to 90 percent of the energy is lost into the atmosphere as heat.
Only 10 percent of the energy at each tier is transferred from one trophic level to the next.

45. ecosystem’s biomass and distribution of organisms
Biomass 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

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

47. The Water Cycle Steps of the Water Cycle Evaporation Condensation
Transpiration
Precipitation

48. Water cycles through the environment.
The hydrologic, or water, cycle is the circular pathway of water on Earth.
Organisms all have bodies made mostly of water.
precipitation
condensation
transpiration
evaporation
water storage
in ocean
surface
runoff
lake
groundwater
seepage

50. Elements essential for life also cycle through ecosystems.
A biogeochemical cycle is the movement of a particular chemical through the biological and geological parts of an ecosystem.
The main processes involved in the oxygen cycle are photosynthesis and respiration.

51. Oxygen cycles indirectly through an ecosystem by the cycling of other nutrients.
respiration
carbon
dioxide
photosynthesis

52. Carbon Cycle Carbon is the building block of life.
The carbon cycle moves carbon from the atmosphere, through the food web, and returns to the atmosphere.
Carbon is emitted by the burning of fossil fuels.
Some carbon is stored for long periods of time in areas called carbon sinks.

54. Nitrogen Cycle The nitrogen cycle mostly takes place underground.
Some bacteria convert gaseous nitrogen into ammonia through a process called nitrogen fixation.
Some nitrogen-fixing bacteria live in nodules on the roots of plants; others live freely in the soil.
soybeans

56. The phosphorus cycle takes place at and below ground level.
Phosphate is released by the weathering of rocks.
Phosphorus moves through the food web and returns to the soil during decomposition.
Phosphorus leaches into groundwater from the soil and is locked in sediments.
Both mining and agriculture add phosphorus into the environment.
geologic uplifting
rain
weathering of
phosphate from rocks
runoff
sedimentation
forms new rocks
leaching
phosphate in solution
animals
plants
decomposers
phosphate
in soil