1. Principles of Ecology
Chapter 2

2. Principles of Ecology
Ecology – study of relationships between living and nonliving parts of the world
Ernst Haeckel (1866) – first to use the word to name the study of how organisms fit into their environment
Ecologists: Scientists who study Ecology

3. Parts of the Environment
Abiotic Factors – non-living parts of an organism’s environment Air currents, temperature, moisture, light, soil
Biotic Factors – all the living things that inhabit the environment
- salmon, bears, trees, algae,
microscopic organisms

4. Levels of Organization
Organism
Population
Community
Ecosystem
Biome
Biosphere

5. Niche vs. Habitat Habitat – place an organism lives out its life
Niche – role and position a species has in its environment
Includes all biotic and abiotic interactions as an organism meets its needs for survival
If two species are competing for the same niche, one will most likely drive the other out and take control of the niche.
What is your niche?

6. Niche vs. Habitat vs. Ecosystem
A great blue heron that lives around the Wye Marsh is part of the Wye river ecosystem. The heron and its mate eat fish, frogs, salamanders, snakes, crayfish, mice, aquatic insects, crickets, grasshoppers, and a variety of other insects in Georgian Bay and the Wye Marsh and build a nest in a tree along side the marsh.
What is the heron’s habitat?
What is the heron’s niche?
What is the heron’s ecosystem?

7. Community Interactions
Interactions in a community include competition for basic needs such as food, shelter, and mates, as well as relationships in which organisms depend on each other for survival
Competition – Occurs when one or more organism uses a resource at the same time
Water during a drought
Predation – One organism consuming another organism for food
Predator – the organism that pursues
Prey – the organism that is pursued

8. Relationships
All living things form relationships with other living things
Symbiotic Relationship – a relationship between organisms of two different species that live together in direct contact

9. Commensalism One organism benefits – The other is not affected
Spanish moss on a tree
Barnacles on a whale
Burdock seeds on a passing animal

10. Mutualism Both organisms benefit
Acacia tree and ants (Pseudomyrmex sp.) – tree provides food for the ants and the ants protect the tree from animals that would eat the leaves
Lichens: algae and fungus living together Algae provides food (photosynthesis) and the fungus provides protection and attaches the lichen to the rock or wood where it lives.

11. Parasitism One organism benefits, the other is harmed
Some live within the host
Tapeworms
Heartworms
Bacteria
Some feed on the external surface of the host
Ticks
Fleas
Mistletoe
Most do not kill their host (at least not quickly)

12. Ecosystem Requirements
#1 - Continuous supply of Energy
#2 – A flow of energy from one population to another

13. Obtaining Energy
Autotrophs - use energy from the sun or energy stored in chemical compounds to produce energy
Heterotrophs – must consume their energy
Herbivores
Carnivores
Omnivores
Detritivore (AKA decomposers)

14. Herbivores
Eat plants (autotrophs)

15. Carnivores Eat other heterotrophs Predators – kill their own food
Scavengers – eat animals that are already dead

16. Omnivores
Eat both autotrophs and heterotrophs (plants and animals)

17. Decomposers and Scavengers
Decomposers – decompose organic matter and
return nutrients to soil, water, and air.

18. Energy Pyramid The energy pyramid is made of several trophic levels
Trophic Level- feeding level in a food chain or food web
Autotrophs make up the first level, and heterotrophs make up the remaining levels
Organisms at each level get their energy from the level before it

19. Food Chains
A simple model that shows how energy flows through an ecosystem
Energy flows in one direction

20. Food Chain

21. Food Webs
Food Web – a model that represents the many interconnected food chains

23. Ecological Pyramids
The number of organisms and amount of energy at each trophic levels decreases as you step up the pyramid.
Biomass (living organic matter) is reduced at each trophic level as well

25. Cycles of Matter
The bodies of all organisms are built from water and nutrients such as carbon, nitrogen, and phosphorus
Matter changes form, but is neither created nor destroyed; it is recycled continuously within and between ecosystems
Essential nutrients are cycled through biogeochemical processes
Biogeochemical Cycle: The exchange of matter through the biosphere. These cycles connect living organisms (bio), geological processes (geo), and chemical processes (chemical)
Organisms are an important part of this cycling system.

26. Water Cycle
Water is a necessary substance for the life processes of all living organisms.
Water is found in the atmosphere, on the surface of Earth and underground, and in living organisms.
The water cycle, also called the hydrologic cycle, is driven by the Sun’s heat energy, which causes water to:
evaporate from water reservoirs (the ocean, lakes, ponds, rivers)
condense into clouds
then precipitate back to water bodies on Earth in the form of rain, sleet, or hail

28. Carbon Cycle
All living things are composed of molecules that contain carbon
Carbon and oxygen make up molecules essential for life, including carbon dioxide and simple sugar
Organisms play a major role in recycling carbon from one form to another
During photosynthesis, plants release carbohydrates and oxygen back into the air
These carbohydrates are used as a source of energy for all organisms in the food web

29. Nitrogen Cycle Nitrogen is an element found in proteins
Nitrogen is found in the atmosphere, but organisms cannot use nitrogen directly from the atmosphere
Nitrogen is captured from the air by species of bacteria that live in water, the soil, or grow on the roots of some plants
This process is called nitrogen fixation

30. Nitrogen Recycling Processes
Nitrogen is introduced into the soil through precipitation
They can also come from fertilizers
Plants absorb nitrogen compounds from the soil and convert them into proteins
Animals eat the plants and use the nitrogen to build protein
When organisms poop, pee, or die, decomposers break them
down and the nitrogen is returned to the soil in the form of
ammonia
7. Organisms in the soil convert ammonia into nitrogen compounds
and soil bacteria convert nitrogen compounds back into nitrogen
gas in a process called denitrification

31. The Phosphorous Cycle
Phosphorus is essential for the growth and development of organisms
In the short-term cycle, phosphorus is cycled from the soil to producers, and from producers to consumers
In the long-term cycle, erosion of rocks that contain phosphorus slowly adds phosphorus to the cycle