1. Principles of Ecology
Chapter 13

2. Ecologists Study Relationships
Interactions and Interdependence
Ecology – the scientific study of interactions among living things and their surroundings
Basically, ecology is the study of nature’s houses. It can involve anything from single cells to entire planets.

3. Ecologists Study Relationships
Biosphere - part of a planet (the earth) in which life exists including land, water, and air
A biosphere is the largest of the “houses” in a biosphere.
For the earth it can extend from 8 km above the earth to 11 km below the surface of the ocean

4. Ecologists Study Relationships
Populations – individuals that live in the same area
Species – a group of individuals that can interbreed

5. Ecologists Study Relationships
Communities – assemblages of different populations that live together
Communities are within the ecosystem (Ex. A reef in the ocean)

6. Ecologists Study Relationships
Ecosystem – a collection of all organisms that live in a particular place with their nonliving, or physical environment
Scientists often study species, populations, or communities in an ecosystem.
the collection of components and processes that comprise, and govern the behavior of, some defined subset of the biosphere. The term is generally understood to refer to all biotic and abiotic components, and their interactions with each other, in some defined area, with no conceptual restrictions on how large or small that area can be.
The breakdown is from largest to smallest – communities (assemblages of different populations) to populations (groups of individuals that belong to the same species and live in the same area) to species (A species generally consists of all the individual organisms of a natural population which are able to interbreed, generally sharing similar appearance, characteristics and genetics due to having relatively recent common ancestors.)

7. Ecologists Study Relationships
Levels of Organization
Biome – a group of ecosystems that have the same climate and similar dominant communities
Within a biosphere is a biome.
a biome is a major regional group of distinctive plant and animal communities best adapted to the region's physical natural environment, latitude, altitude, and terrain. A biome is made up of communities at stable steady state and all associated transitional, disturbed, or degraded, vegetation, fauna and soils, but can often be identified by the climax vegetation type.

8. Ecologists Study Relationships
Ecological Methods
Observing – first step
Long term studies more beneficial-ecological change takes time
Surveys
Direct
Indirect
Determining Population Size
Catch and release
Quadrat Sampling
Ecologists can do visual surveys – direct or indirect
Direct – used for species that are easy to follow; watch with the naked eye or with tools like binoculars or scopes
Indirect – used for species difficult to track; use signs of presence like feces or urine or a recent kill
Radio Telemetry – used to monitor populations-animal fit with a radio collar that transmits a radio signal and used to track the animal
Catch and release – used to determine population size – catch and mark members of population; then re-catch later and determine number of tagged to untagged
Quadrat sampling – dividing the plots into retangular frames-count the number of plants in each plot and then use a computer formula to determine the total number of plants in the entire area

9. Ecologists Study Relationships
Experimenting – used to test hypotheses
Can do in the field or lab
Lab-more control, not a true reflection
Field-More accurate, difficult to determine cause and effect relationships
Lab-controlled setting used to focus on a very specific part of the ecosystem
Field-performed where the organism lives

10. Ecologists Study Relationships
Modeling – gain insight
Computers
Mathematical models
Use actual data to simulate
Data collected using satellite technology

11. Biotic and Abiotic Factors
Living and Non-living components
Biotic - living factors
Abiotic - nonliving things

12. Biotic and Abiotic Factors
Biodiversity
The assortment, or variety of living things
Dependent on temperature, moisture
Keystone Species – species that have a large impact on ecosystems
Rainforests cover less than 7% of the earth’s surface, but contain 50% of the earths plant and animal species
Beavers are a keystone species-they build dams which reduce water flow, which allows a greater variety of fish to live in the pond-fish attract birds such as herons and kingfishers-insects live in the trees-these insect attract other birds-shrubs grow on the edges of ponds attracting even more birds-animals that prey on bird eggs or the birds themselves are attracted to the area

13. Energy in Ecosystems Producers – organisms that make their own food
Autotrophs – organisms that use energy from the sun or chemicals to make food
All the energy on earth comes from the sun.
Only 1% of the energy that comes from the sun that reaches the earth is used by living things for energy.

14. Energy in Ecosystems Energy from the sun
Photosynthesis – Autotrophs use light energy to power chemical reactions that make energy
Uses CO2
Makes O2 and Carbs
On land, plants are the main autotrophs.
In the water, algae is the main photosynthesizer. There are some baceteria (cyanobacteria).
Cyanobacteria are major producers in the ocean producing oxygen.

15. Energy in Ecosystems Life without light
One such bond is hydrogen sulfide, or iron monosulfide.
Life without light
Chemosynthesis – Use chemical energy to make carbohydrates
Bacteria deep in the ocean

16. Energy in Ecosystems
Consumers – Organisms that need other organisms for their energy and food supply
These are also referred to as heterotrophs

17. Food Chains and Food Webs
Feeding Relationships
Food Chains – A series of energy transferring steps

18. Food Chains and Food Webs
Types of heterotrophs
Herbivores
Energy from eating plants
Carnivores
Energy from eating animals
Omnivores
Both plants and animals
Detritivores
Feed on the remains of dead matter
Decomposers
Break down organic matter for energy
Herbivores – cows, catepillars
Carnivores – snakes, dogs, owls
Omnivores – humans, bears, crows
Detrivores – mites, earthworms, snails, crabs
Decomposers – bacteria and fungi

19. Food Chains and Food Webs
Specialist
Consumer that primarily eats one specific organism
Generalist
Have a varying diet
Snail kites eat only apple snails for food

20. Food Chains and Food Webs
Trophic Levels – Each step in a food chain or web
First level is producers
Second level on is consumers-usually herbivores
Tertiary consumers are usually carnivores
Each consumer depends on the trophic level below it

21. Food Chains and Food Webs
Food Webs – Feeding relationships among many organisms in an ecosystem form a network of interactions
Decomposers will convert the dead plant material to detritus - is non-living particulate organic material (as opposed to dissolved organic material). It typically includes the bodies of dead organisms, fragments of organisms or faecal material, and is normally colonised by communities of microorganisms which act to decompose (or remineralize) the material.

22. Cycling of Matter The Hydrological Cycle (Water Cycle)
Evaporation – Water changes from a liquid to a gas
Transpiration – Evaporation from the leaves of a plant
The water we need cycles between the ocean, atmosphere, and land.
Water is evaporated from the ocean. It can also enter the atmosphere by a process called transpiration from plant
As the water vapor rises due to heating from the sun, it eventually begins to cool and condensation occurs.

23. Cycling of Matter
Clouds form from tiny drops of water collecting called condensation

24. Cycling of Matter Recycling in the Biosphere Biogeochemical cycles
The transforming of matter by biological systems
Energy moves in a one way fashion – Nutrients recycle
Energy flows one way in a biosphere; matter is continuously recycled in and between ecosystems.
Elements, compounds, and other forms of matter are passed from one organism to another and from part of the biosphere to another.
The reason it continues to recycle through the biosphere is that organisms do not use up matter, they transform it. – It is either assembled into body tissues or excreted as waste.

25. Cycling of Matter Nutrient Cycles
Nutrient – All the chemical substances that an organism needs to sustain life
Nutrients cycle through an ecosystem just like a biogeochemical cycle.

26. Cycling of Matter Oxygen Cycle Most organisms use oxygen need oxygen
Plants release oxygen
Living organisms release carbon dioxide as a waste product

27. Cycling of Matter The Carbon Cycle
Carbon is passed on from one situation to another throughout the biosphere
Photosynthesis uses CO2 to make carbs
Carbs are eaten by other organisms
Organisms exhale CO2 during cellular respiration
All organisms eventually decay and the carbon is converted to coal or petroleum
Burning things releases stored CO2 into the atmosphere
Remember, carbon is one if not the most important element to living things – it makes the macromolecules we need to survive.

28. Cycling of Matter The Nitrogen Cycle
All organisms need nitrogen to make amino acids
What do amino acids make?
Proteins
78% of Earth’s atmosphere
Nitrogen gas (N2)
Other types:
Ammonia (NH3)
Nitrate (NO3)
Nitrite (NO2)
Nitrogen fixation – N2 to NH3
Denitrification - NO3 to N2
There are many types of naturally occurring nitrogen.
Although N gas is the most abundant gas in the atmosphere only a few select bacteria can actually use it directly. They are usually attached to the roots of plants called legumes.
They convert nitrogen gas to ammonia through nitrogen fixation
Denitrification releases nitrogen from dead plants back into the atmosphere

29. Cycling of Matter The Phosphorus Cycle DNA and RNA need phosphorus
This element does not go into the atmosphere
Phosphorus works its way through the food web

30. Cycling of Matter Nutrient Limitation
Ecologists look at the rate of production of producers – Primary Producivity
Availability of nutrients can limit an ecosystem
Limiting nutrient
Ecosystem limited by one nutrient
Nitrogen in the ocean is the limiting nutrient
% nitrogen
If runoff causes a drastic increase in nitrogen, then an algae bloom occurs
Farmers apply fertilizer because of limiting nutrients
Algae bloom becomes a primary producer

31. Pyramid Models
Ecological Pyramids – diagram that shows how much energy is transferred at each trophic level

32. Pyramid Models Biomass Pyramid
Biomass – Total amount of living tissue in a level
Represents the amount of potential food available at each trophic level

33. Pyramid Models Energy Pyramid
Only about 10 % of the energy is transferred to the next trophic level
More levels means less energy at the last level
One tenth of the solar energy captured by grasses ends up stored in the tissues of cows. Only 10% of 10% (1%) is transferred to humans that eat the cow.

34. Pyramid Models Pyramid Numbers
Shows how many individuals there are in each level