Ecology Overview

Ecology Overview

Ecology is a way of looking at the interactions between organisms and between organisms and their surroundings, which is often called an ecosystem (in the big picture, the biosphere).

Ecology is the field of biology that looks at our environment and what goes on in our surroundings.

When we study ecology we ask questions and make observations about our surroundings. We regularly ask why certain organisms live where they do?
We can see that:

Different organisms are found in different places
There are only a few basic types of communities, or biomes, on earth which extend over large land masses

Ecological studies try to find out what characteristics the organisms have which give them an advantage in their surroundings, and to find out what are the critical factors of that ecosystem that help determine the successful characteristics.

So in the study of ecology we look at the:

Structure of ecosystems (what's there)
Processes occurring in ecosystems
Community Interactions
Biomes: the types of Ecosystems and the characteristic climatic features and organisms that inhabit specific biomes

Abiotic (Non-living) Components of Ecosystems
Climate

Solar radiation
- Air circulation (wind patterns)
  - Precipitation patterns
- Light
- Heat (temperature)
Atmosphere
Substrate (mostly soils)

Dynamics of Ecosystems (Both Biotic and Abiotic Components)
Energy Flow in Ecosystems

Trophic Levels (Who eats Whom?)
- Sun
- Producers
- Consumers
  - Herbivores
  - Carnivores (1 , 2 , 3 etc.)
  - Reducers (Decomposers)
Energy Flow Patterns
- Pyramids
  - Energy pyramids
  - Number pyramids
  - Biomass pyramids
- Usefulness of one pyramid level biomass to next level
  - Efficiency of obtaining energy source
  - Ratio of nutrients to food volume
  - Metabolic rates of consumers/reducers
- Trophic Levels, Complexity and Food Webs

Nutrient Cycles

Energy used by living organisms is chemical energy so major process of ecosystem is movement of nutrients
Some nutrient cycles
- Carbon
- Nitrogen
Human impacts on nutrient cycles
- Modifying amounts, form and location of nutrients

Community Interactions (Population Regulations) (Adjusting to the Carrying Capacity)

Interactions that help to maintain populations at carrying capacity
- Competition
- Predation
  - Plant-herbivore
  - Predator-prey
  - Mutualisms
  - Commensalisms

We tie characteristics of the environment together when we look at Biomes (and the Aquatic Life Zones for aquatic ecosystems). For biomes we look at features of climate, characteristic vegetation, typical consumers, special needs (adaptations) for survival, and human impacts on the biome.

Types of Terrestrial Biomes

Tundra
Coniferous Forest (Taiga)
Temperate deciduous Forest
Deserts
- Hot
- Cold
Scrub or Mediterranean Forest
Grasslands
Savanna
Tropical Forests
- Rain or Evergreen
- Deciduous
Other Forests

Aquatic Life Zones (Ecosystems)

Lake Ecosystems
- Lake zones
- Seasonal lake changes
- Nutrient nature of lakes
Marine Ecosystems
- Types
- Estuaries
- Coastal
- Open ocean