EcologyIntroduction

What is it?The study of living things and

how they interact with nonliving things.

Each organism depends in some way on other living or nonliving things.

Levels of organization

• Biosphere: Broadest level of organization including all things found on Earth and in it’s atmosphere.

• Ecosystems: Includes all the organisms and the nonliving environment found in a particular place.

• Community: Only includes living parts of the ecosystem.

Levels of organization

• Population: Includes all the members of a species that live in one place at one time.

• Organism: Simplest level of organization that consist of only on living thing.

Example: Biosphere

•Think of it this way: If the earth were an apple the biosphere would be only as thick as the skin on the apple.

•Living things are not distributed evenly throughout the biosphere.

Example: Ecosystem• A pond is an ecosystem that contains

a variety of living things: fish, turtles, aquatic plants, algae, insects, and bacteria.

Also don’t forget the nonliving: chemical and physical composition (water, sunlight)

• They all interact in ways that affect their survival.

Example: Community

• All the living organisms in the pond: fish, turtles, pants, algae, and bacteria.

• Can contain thousands of species

Example: Population• All the members of a species that

live together at one time. Like a species of frogs living in the same pond and interacting.

Example: Organism• One single organism like a duck.

Biotic and Abiotic Factors

• Biotic: all the living things in environment: animals, plants, bacteria, etc.

• Abiotic: all of the non-living things in environment: pH, salinity, temp, minerals, amount of sunlight, and precipitation.

Biotic and Abiotic interactions

Abiotic and Biotic factors are not independent.

Ex: Plants (biotic) need nitrogen (abiotic)

The Niche

• A species’ niche is its way of life, or role the species plays in its environment.

• A species niche includes a range of things: – Methods of how it obtains food– Number of offspring– Time of reproduction– All other interactions with its environment

Niche Differences

• A species niche can change in a single generation.

• Some species survive better than others.

Specialist: have narrow niches• Ex. Koala who feeds

only on a few species of eucalyptus leaves.

Generalist: tolerate a broad range of things• Ex. Virginia Opossum

lives all over the U.S. and eats almost anything

Questions – Chapter 19• 1. Describe 3 abiotic factors that can

affect an organism. • 2. How are biotic and abiotic factors

interdependent?• 3. How is an organism’s niche different

from its habitat. • 4. Completely describe the niche of a

squirrel.• 5. Define and compare dormancy and

migration.

Questions – Chapter 19• 6. Name 5 different populations.• 7. What is the difference in immigration

and emigration?• 8. What is exponential growth?• 9. What is the shape of an exponential

growth curve?• 10. How many people lived on Earth

10,000 years ago? How many live on Earth today (1999)?

• 11. Why has human growth rate increased so dramatically?

Species Interactions

Several types:

1. Predation – predator captures, kills, and consumes prey

Important role in natural selection

Avoiding predators - cont

• a. Camouflage -hiding

Avoiding predators - contb. Advertising poison –

caterpillars eat poisonous plant

Avoiding predators - cont

c. Mimicry – harmless species resembles a dangerous or distasteful one.

Harmless viceroy (bottom) looks like poisonous monarch butterfly.

Avoiding predators - cont

d. Looking scarey

2. Parasitism – one individual, the parasite, feeds on another individual, the host

a. Ectoparasites: live externally.

Ex. Fleas, ticks, lice, leeches, lampreys

b. Endoparasites: live internally.

Ex. Flukes, tapeworms, disease-causing bacteria

Highly adapted – may lack digestive system, limbs, etc

4. Competition – results from the use of same resources by 2 or more species.

5. Mutualism – cooperative relationship between 2 organisms in which both benefit.

Ex. Sea anemone and clown fish;

Acacia tree and ant

6. Commensalism – interaction in which one species benefits, the other is not helped or harmed

Ex. Cattle and egrets

Communities Change• Succession –

gradual regrowth of species in an area

A. Primary – development of community in an area not previously inhabited.

Ex. New island (bare rock), sand dune, lava flow

• http://bcs.whfreeman.com/thelifewire/content/chp55/55020.html

• Primary succession of a moraine

B. Secondary – replacement of species after a disruption (by fire, storm, human activity)

Pioneer species – the first to appear in succession;

small and fast growing

Ex – lichen

Climax Community – Stable, mature ecosystem. Stays the same a long time.

Ex – Forest, prairie

Pioneer Climax