1. What is Ecology?

2. What is Ecology?
* Ecology is the study of interactions among organisms and between organisms and their environment.

3. Levels of Organization
Biosphere – contains the combined portions of the planet in which all of life exists, including land, water, and air/atmosphere. It is our planet as a whole and where ecology takes place.
Biome – a group of ecosystems that have the same climate and similar dominant communities.
Ecosystem – a collection of organisms that live in a particular place along with their non-living, or abiotic, environment.
Communities – assemblages of different populations living together in a defined area.
Populations – groups of individuals that belong to the same species and live in the same area.
Species – a group of organisms that can breed and produce fertile offspring.
Example:
Whole Planet ↓
Temperate Forest
Pond, plants, animals, water, O2, rocks
Pond, frogs, fish, plants, algae
All bullfrogs in pond
Bullfrog
Biotic Factor = living organisms influencing the environment
Abiotic Factor = non-living influences on environment

4. Ecological Levels of Organization

5. How to Study Ecology Three ecological methods: Observing Experimenting
Modeling

6. How to Study Ecology (continued)
Observing – first step in asking ecological questions and may form the first step in designing experiments and models.
Experimenting – used to test hypotheses, and may be artificially set up in a laboratory or conducted within natural ecosystems.
Modeling – models are needed to learn about ecological processes and events that happen over long periods of time (ex. global warming).

7. Energy Flow
**** Sunlight is the main energy source for life on Earth.****

8. Energy Flow (continued)
Autotrophs – Producers – produce their own food using sun or chemicals
Plants and algae - by photosynthesis (sun’s energy)
Some bacteria – by chemosynthesis (chemical energy)
Heterotrophs – Consumers – rely on autotrophs for food
Herbivore – eat autotrophs directly
Carnivore – eat herbivores
Omnivore – eat both autotrophs and heterotrophs
Detritivores – eat dead plant and animal material
Decomposers – break down organic material and release nutrients

9. Feeding Relationships
*Energy flows through an ecosystem in one direction, from the sun or inorganic compounds to autotrophs (producers) and then to various heterotrophs (consumers).

10. Food Chains Food Chains –
algae → zooplankton → small fish → squid → shark
(notice direction of the arrowheads!!!)
This food chain idea works for simple food chains but....

11. Food Webs
…Food webs are able to show the complexity of more complicated ecosystems
Food webs link all food chains in an ecosystem together

12. A Marsh Food Web

13. Food Webs (continued)
Trophic Levels – each step in the food chain or food web is called a trophic level. Producers are the first level and consumers are the second or higher level(s).

14. Ecological Pyramids
****Energy Pyramid – only 10% of energy can be transferred to next trophic level because organisms use energy for respiration (breathing), movement, and reproducing. More levels between a producer and a top-level consumer means less energy remains from original amount = limited food chain length supported.****
Biomass Pyramid – shows amount of potential food for each trophic level (grams per unit area)
Pyramid of Numbers – shows number of individuals at each trophic level.

15. Ecological Pyramids Energy Pyramid Shows the relative amount of
energy available at each trophic
level. Organisms use about 10
percent of this
energy for
life processes.
The rest is lost
as heat.
Pyramid of Numbers
Shows the relative
number of individual
organisms at each
trophic level.
Biomass Pyramid
Represents the amount of
living organic matter at each
trophic level. Typically, the
greatest biomass is at the
base of the pyramid.