Chapter 2 – Principles of Ecology

Organisms and their Environment

1. ECOLOGY is the study of interactions that take place between organisms and their environment.

What is Ecology

1. The BIOSPHERE is the portion of Earth that supports living things

a) Extends from highest mountain to the bottom of the oceans

i. Airii. Landiii. Fresh/Salt Water

The Biosphere

1. The nonliving parts of an organism’s environment are called ABIOTIC FACTORS

a) Air currents, Temperature, Water, Sunlight, Soil

2. All living organisms that inhabit an environment are called BIOTIC FACTORS

Abiotic and Biotic Factors

1. Organism – a single individual

2. Population – a group of the same species in the same place at the same time

3. Community – all living things; interacting populations

4. Ecosystem – all biotic and abiotic factors

5. Biosphere – The portion of Earth that supports life

Levels of Organization In Ecology

1. Organism

2. Population

3. Community

4. Ecosystem

5. Biosphere

Two Types of Ecosystems

1. Terrestrial – located on landa) Forest, Desert, Rotting Log, Mountain

2. Aquatic – Located in fresh or salt watera) Ocean, Lake, River, Pond

1. A HABITAT is the place where an organism lives its life

a) Forest, bottom of the ocean, desert, coral reef

Habitat

1. When several species share the same habitat and use the same resources, COMPETITION may result

2. Using different resources leads to reduced competition

Competition

1. A NICHE is an organism’s role in its environment; how it obtains energy

a) What it eats, how it eats, where it lives, etc.

2. Most of the time different species occupy different niches (reduced competition)

3. When two species have the exact same niche, competition will eventually force one species to either die out or find a different niche

Niche

Lions kill prey and eat meat Monkeys climb trees and eat fruits and insects

Whale sharks swim and eat plankton Trees use sunlight to make food

Survival Relationships

1. PREDATORS hunt and eat other organisms2. The animals predators eat are called PREY

PREDATOR

PREY

1. SYMBIOSIS is a close and permanent relationship between organisms of different species

2. SYM = together; BIOSIS = living

3. 3 types of symbiosis:a) Mutualismb) Commensalismc) Parasitism

Symbiosis

1. A symbiotic relationship between two species where both species BENEFIT (+,+)

a) E.g. Bees and Flowers. Bees benefit by using nectar from flowers for food and honey; flowers benefit because bees carry pollen from flower to flower to help the flowers reproduce (pollination)

Mutualism (+,+)

1. A symbiotic relationship between two species where one species benefits and the other is neither harmed nor benefited (+,0)

a) E.g. The remora, a small sucker fish, attaches to a shark and rides along with the shark. The remora gets protection from predators and scraps of food that the shark doesn’t eat; the shark is unaffected by the remora.

Commensalism (+,0)

1. A symbiotic relationship where one species benefits and the other species is HARMED;

a) The organism that is being harmed is called the HOST; the parasite usually does not kill the host because the parasite relies on the host for survival

i. E.g. Tick sucking the blood of a dog

Parasitism (+,-)