1. 13.1 Ecologists Study Relationships

2. Introduction To Ecology
Ecology – the study of living things and their relationship with each other and with the environment
*Ecology can be studied at different levels, from a local to a global scale

4. Levels of Organization
1. Organism – an individual living thing, such as an alligator
2. Population – group of same species that lives in one area, such as a group of alligators living in a swamp

5. Levels of Organization
3. Community – all of the living things in a given area. Ex: alligators, fish, plants, birds.
4. Ecosystem –
all of the living and
nonliving things
in a given area.
Ex: All of the above and
soil, rocks, water, etc.

6. Levels of Organization
5. Biome – a major regional or global community of organisms, usually characterized by the climate conditions and plant communities that thrive there.
Examples: tropical, grassland, desert, temperate, taiga, tundra

7. Levels of Organization
6. Biosphere – portion of the Earth where all life exists

9. Ecological research methods include…
Observation – the act of carefully watching something over time.
Direct: naked eye, binoculars
Indirect: feces, recent kill
Experimentation – scientists can perform experiments in the lab or the field.
Modeling – Using computer or mathematical models to describe and model nature

10. 13.2 Biotic and Abiotic Factors
Every ecosystem includes both living and nonliving factors

11. Biotic factors are living things, or things that were once living
Examples: plants, animals, fungi, bacteria
Each organism plays a particular role in the ecosystem.

12. Abiotic Factors are nonliving
Examples: moisture, temperature, wind, sunlight, soil.
The balance of these factors determines which living things can live in a particular environment.

13. Biodiversity is important to an ecosystem
Biodiversity is the assortment, or variety, of living things in an ecosystem.
Keystone species: A species that has an unusually large effect on its ecosystem. The loss of a keystone species from an ecosystem can have a ripple effect.
Example: Beavers create dams which are an ecosystem used by a wide variety of species.

14. 13.3 Energy in Ecosystems
Life in an ecosystem requires a source of energy
Producers provide energy for other organisms in an ecosystem.
Producer: An organism that get their energy from non-living resources. Example: Plants
Also called autotrophs
Get energy from photosynthesis or chemosynthesis
Chemosynthesis: process by which an organism forms carbohydrates using chemicals as an energy source.

15. Energy In Ecosystems
Consumers are organisms that get their energy by eating other living things
Also called heterotrophs
All consumers somehow depend on producers for food.
Examples: wolf, human, rabbit

16. 13.4: Food chains and food webs
Food chains and food webs model the flow of energy in an ecosystem.

17. Food Chains & Food Webs Food chain: a model that shows a sequence of
feeding relationships.
Shows the transfer of
energy from one
organism to another
Each level of
nourishment
in a food chain is
called a trophic level

18. Not all consumers are alike.
Herbivores: Eat only plants. Example: rabbits
Carnivores: Eat only animals. Example: lion
Omnivore: Eat both plants and animals. Example: kangaroo rat.
Detritivores: Eat detritus, or dead organic matter.
Examples: millipede
Decomposer: A type of detritivore that breaks down organic matter into simpler compounds, returning vital nutrients back into their environment.
Example: fungi

19. Other types of consumers…
Specialists: a consumer that primarily eats one specific organisms or feeds on a very small number of organisms.
Very sensitive to changes in the availability of prey.
Generalists: consumers that have a varying diet (most species).

20. Energy flows from the lowest trophic level to the highest trophic level
Producer to primary consumer to secondary consumer to tertiary consumer
Primary consumers are herbivores (or omnivores)
Secondary consumers are carnivores (or omnivores)
Tertiary consumers are carnivores (or omnivores)

21. A food web is a model that shows the complex network of feeding relationships and the flow of energy within an ecosystem.

22. Energy Pyramids
A pyramid of numbers shows the numbers of individual organisms at each trophic level in an ecosystem.
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.
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

23. 3.5 KEY CONCEPT Matter cycles in and out of an ecosystem.
It changes form, but does not disappear.
The total amount of matter remains the same.
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24. 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

25. Elements essential for life also cycle through ecosystems
Elements essential for life also cycle through ecosystems -examples: oxygen, carbon
A biogeochemical cycle is the movement of a particular chemical through the biological and geological parts of an ecosystem.

26. The Oxygen Cycle
Oxygen can cycle indirectly through an ecosystem by the cycling of other nutrients.
oxygen
respiration
carbon
dioxide
photosynthesis

27. The Carbon Cycle Carbon is the building block of living organisms.
Carbon comes in all three forms (solid, liquid, gas)
CO2 gas
HCO3 (bicarbonate- dissolved in water)
Fossil Fuels (underground) oil, natural gas, coal
Carbonate rocks (limestone)
Dead Organic Matter
fossil fuels
photosynthesis
carbon dioxide
dissolved in water
decomposition
of organisms
respiration
carbon
dioxide
in air
combustion

28. 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.
Lightning
can split
nitrogen
molecules in the
atmosphere which
can add nitrogen
to the soil.
nitrogen in
atmosphere
animals
denitrifying
bacteria
nitrifying
ammonium
ammonification
decomposers
plant
nitrogen-fixing
bacteria in soil
bacteria in roots
nitrates
nitrites

29. Nitrogen Cycle Continued
Ammonia (NH3) released into the soil is transformed into ammonium – some is taken up by plants
Nitrifying bacteria change the ammonium into nitrate.
Nitrate is taken up by plants and converted into organic compounds like amino acids and proteins.
Nitrogen moves through the food web and returns to the soil during decomposition as ammonium.

30. Phosphorus Cycle
The phosphorus cycle takes place at and below ground level – it does not include an atmospheric portion.
1. Phosphate is released by the weathering of rocks.
2. Plants and fungi found near plant roots are able to take up phosphate
3. Phosphorus moves through the food web and returns to the soil during decomposition.
geologic uplifting
rain
weathering of
phosphate from rocks
runoff
sedimentation
forms new rocks
leaching
phosphate in solution
animals
plants
decomposers
phosphate
in soil
Phosphorus leaches into groundwater from the soil and is locked in sediments.
Both mining and agriculture add phosphorus into the environment.