Ecology

Goal 5

Chapter 2 T. J. Hill

Goal 5

The learner will develop an understanding of the ecological relationships among organisms.

Objective 5.01

Investigate and analyze the interrelationships among organisms, populations, communities, and ecosystems.Techniques of Field Ecology.Abiotic and Biotic Factors.Carrying Capacity.

I. What is Ecology?

A. The scientific study of interactions among organisms and their environments.

II. Aspects of Ecological Study.

A. Biosphere- portion of earth that supports life.

III. The Nonliving Environment.

A. Abiotic Factors- nonliving elements in an ecosystem.

1. Air

2. Temperature

3. Currents

4. Light

5. Soil

6. Moisture

7. Noise

IV. The Living Environment.

A. Biotic Factors- living elements in an ecosystem (Plants & Animals, Protists, Bacteria).

Biotic or Abiotic?

Biotic or Abiotic?

Biotic or Abiotic?

Biotic or Abiotic?

V. Levels of Organization in Ecology

A. All organisms are dependent on others for food, shelter, reproduction and protection.

B. Interactions within populations.

1. Population- all the individuals of the same species. (must be counted)

2. Community- a collection of interacting populations.

3. Ecosystem- the community plus the physical factors in an area.

a. Three Major Kinds of Ecosystems.

1. Terrestrial- (located on land)

2. Aquatic- (occur in fresh and salt water.)

a. Freshwater Ecosystems- ponds, lakes, streams.

b. Salt Water Ecosystem – also called marine ecosystems make up 75% of earth’s surface.

(Oceans)

Biodiversity- variety of life in an area, usually measured as the number of species can live in an area.

VI. Organisms in Ecosystems (Living Styles)

A. Habitat- the place where organisms live out their lives.

B. Niche- the role and position a species has in its environment.

1. How it meets its needs for food and shelter.

2. How it reproduces.

3. Includes all interactions with the biotic and abiotic parts of its habitat.

VII. Living Relationships

A. Predator- animals

that kill and eat other

animals.

A. Prey- animals that

predators hunt, kill

and eat.

A. Predation- the act of

one organism feeding

on another.

D. Symbiosis- living together.

1. Commensalism -a symbiotic relationship in which one species benefits and the other species is neither harmed nor benefited.

a. Peregrine falcon and the red breasted goose

2. Mutualism- a symbiotic relationship in which both species benefit.

a. ants and the acacia tree

3. Parasitism- a symbiotic relationship in which one organism benefits at the expense of the other.

a. ticks and dogs

VIII. How Organisms Obtain Energy.

A. Producers- carry on photosynthesis.

1. Autotrophs – able to

make their

own food.

a. Plants

B. Consumers- obtain nutrients by eating other organisms.

1. Heterotrophs - can not make their own food. Must feed on other organisms.

a. Animals

3. Scavengers- animals that feed on animals that have already died.

1. Black Vultures 2. Eagles

4. Decomposers- feed on dead or decaying plants or animals.

a. Break them down into simpler molecules.

1. Some bacteria, protozoa, fungi.

IX. Food Chains- Pathways for Matter and Energy.

A. Food Chain- a simple model that scientists use to show how matter and

energy move through an ecosystem.

1. Represents only one possible route for the transfer of matter and energy in an ecosystem.

2. Example

a. algae fish heron

B.Tropic Level- feeding step in a food chain.1. Represent links in the food chain.2. Producers3. 1st Order Heterotrophs

a. Primary Consumers - Herbivore4. 2nd Order Heterotrophs

a. Secondary Consumers - Carnivore or Omnivore

5. 3rd Order Heterotrophsa. Tertiary Consumers - Carnivore or

Omnivore

X. Energy and Tropic Level Facts.

A. The initial source of energy for ecological pyramids is energy from the Sun.

B. Energy decreases as tropic level increases.

C. Population size decreases as the tropic level increases.

D. Only 10 percent of energy is transferred from one tropic level to the next.

XI. Pyramid Facts

A. Pyramid of Numbers show that population size decrease at higher tropic levels.

B. A pyramid of biomass express the weight of living material at each tropic level.

C. The energy that is lost at each tropic level enters the environment as heat.

XII. Cycles of Nature.

A. Water Cycle- Cycle where water is reused over and over again.1. Cycle is controlled by energy from the sun.2. Water is turned to vapor.

a. Vapor is cooled or condenses to clouds.

b. Water builds up in clouds and it rains.3. Rainfall equals the same amount of

evaporated water. (recycled)

XIII. Importance of Water.

1. Water is essential for body to function.2. Water gives plants and animals continuous

life as well as function.3. Water controls drought.4. Water helps to shape earth’s land

structures.5. Water helps to reflect Sun’s harmful rays

back into space.6. Water can be recreational: fishing,

swimming, boating, etc.7. Water can provide Electrical Power.

XIV. Carbon Cycle

A. Carbon cycle starts with autotrophs.

B. During photosynthesis, energy from the sun is used to convert CO2 gas into energy.

C. All life on earth is based on carbon molecules.

D. Atoms of carbon form the framework for proteins, carbohydrates, fats and other important molecules.

XV.Nitrogen Cycle

A. The air is 78% nitrogen.

B. Plants do not use nitrogen from the air but from the soil.

C. Plants use nitrogen to make important molecules such as proteins.

D. Heterotrophs eat plants and convert nitrogen-containing protein into animal nitrogen containing protein.

E. Heterotrophs eat plants and convert plant protein into human proteins.

F. Urine, an animal waste, contains excess nitrogen, thereby returning nitrogen to soil and water.

G. When organisms die, their nitrogen molecules return to the soil.

H. Bacteria also act on these molecules and put nitrogen back to the soil.

XVI. Phosphorus Cycle

A. Phosphorus cycles through the ecosystem in two ways.

B. Plants obtain phosphorus from the soil.

C. Animals obtain phosphorus by eating plants.

D. When animals die, they decompose and return back to the soil. (Short-Term Cycle)

E. Long-Term Cycle is when phosphates wash into the sea and are incorporated into rock as insoluble compounds. These rock years later weather returning the phosphorus back to the local ecosystem again.