Essentials of Ecology

WHAT IS ECOLOGY?

Ecology = the study of interactions between organisms and their environments, focusing on energy transfer

Ecology is a science of relationships

WHAT DO YOU MEAN BY ENVIRONMENT?

The environment is made up of two factors:

• Biotic factors- all living organisms inhabiting the Earth

• Abiotic factors- nonliving parts of the environment (i.e. temperature, soil, light, moisture, air currents)

Organism

Population

Community

Biosphere

Ecosystem

Biome

Ecologists follow

an organization

system like this

Biosphere - life supporting portions of Earth composed of air, land, fresh water, and salt water.

Biome =

A specific geographic area, characterized by the climate conditions and plant communities that thrive there.

Ecosystem = populations in a community and the abiotic factors with which they interact

Community = several interacting populations that inhabit a common environment and are interdependent.

Population =

a group of organisms of one species living in the same place at the same time that interbreed

Organism = any unicellular or multicellular form exhibiting all of the characteristics of life; an individual.

There are 5 main types of biomes that can be further subdivided:

1. Aquatic

• Water provides an environment for many invertebrates, aquatic species, algae, and minerals

• The largest biome, covering 75% of Earth’s surface

• Divided into freshwater, and marine (ocean) regions

2. Desert

• Receive very little rainfall

• Few plants and animals are adapted to the dryness

• Cover about 1/5 of Earth

• Desserts can be hot or cold, for example Antarctica

3. Forest

• Tropical Rainforest: lush and warm, with high humidity and lots of rainfall, to support a variety of species

• Temperate Forest: goes through 4 seasons and has deciduous trees (trees with leaves) that change colors and go dormant

• Chaparral: Very hot and dry, with some rain in the winter, making them prone to drought and fires (like the forest areas in California)

• Taiga: long cold winters, where conifer trees (trees with needles) thrive

4. Grassland

• Vegetation is dominated by grass and brush

• Occur naturally on all continents, except Antarctica

– Savanna: found in Africa, South America, Australia and India, with wet summers and dry winters

– Temperate Grasslands: what we refer to as “prairies,” found in North and South America and Eastern Europe

5. Tundra

• The coldest of the biomes, with little rain, or vegetation and few animals

• Surrounds the north pole

Symbiotic Relationships

Symbiosis = two species living together and interacting with each other

There are 3 Types of symbiosis:

1. Commensalism

2. Parasitism

3. Mutualism

Commensalism:

one species benefits

and the other is neither

harmed nor helped

Ex. orchids on a tree

A plant, such as a tropical orchid or a bromeliad, that grows on another plant upon which it depends for mechanical support but not for nutrients, neither helps, nor harms the tree.

Parasitism:

one species benefits (parasite) and the other is

harmed (host)

• Example: Tapeworm, fleas, leeches, etc.

Mutualism-beneficial to bothspecies

Ex. cleaning birdsBirds benefit by getting food(insects), while the host (often azebra, or rhinoceros) benefits byreceiving pest control

Make sure to summarize what you learned at the end of the notes.