Chapter 2 –
Principles of
Ecology
2.1 Organisms and Their Relationships
Vocabulary List
ecology
biosphere
biotic factor
abiotic factor
population
biological community
ecosystem
biome
habitat
niche
predation
symbiosis
mutualism
commensalism
parasitism
Ecology
• Organisms depend on each other in all types of
environments — deserts, tropical rain forests, and grassy
meadows.
Ecology
• The study of the interactions between organisms and
their environments
What is Biosphere?
What is Biosphere?
• The thin layer of air, land, and water on or near Earth’s
surface in which all living things on Earth exist.
What is Biosphere?
• The biosphere supports a wide variety of organisms in
a wide range of environments.
What is Biosphere?
Every environment, such as a rainforest, contains living
and non-living factors (components)
LIVING factors = BIOTIC factors
Plants
Animals
Fungi
Bacteria
NON - LIVING factors = ABIOTIC factors
Sunlight
Soil
Moisture
Temperature
Levels of Organization
• The biosphere is too large to study all the relationships
at one time.
• We use smaller pieces, or levels of organization, for
their studies.
1. organism
2. population
3. biological community
4. ecosystem
5. biome
6. biosphere
Organisms, Populations, and Biological
Communities
Organisms
An individual
living thing, such as
one striped fish
Organisms, Populations, and Biological
Communities
Population
A group of
organ isms of the same
species that interbreed and
live in the same place at the
same time, such as the school
of striped fish,is a population.
Organisms, Populations, and Biological
Communities
Community
All of the populations of
species (fishes, coral,
and marine plants) that
live in the same place at
the same time
Ecosystems, biomes, and the biosphere
Ecosystems
A biological community,
such as the coral reef,
and all of the abiotic
factors, such as the sea
water, that affect it.
Ecosystems, biomes, and the biosphere
Biome
A biome is formed by a group of
ecosystems (the coral reefs off the
coast of the Florida Keys) that share
the same climate and have similar
types of communities.
Ecosystems, biomes, and the biosphere
Biosphere
The highest level of organization
is the biosphere composed of many
biomes
Ecosystem Interactions
 Organisms increase their chances of survival by using
available resources in different ways.
 Birds might use a tree for shelter, while insects use the
tree’s leaves for food.
Ecosystem Interactions - Habitat
A habitat is an area where an organism lives
An insect might spend its entire life on one tree. Its habitat is that
tree.
A bird flies from tree to tree. Its habitat is the grove of trees.
Ecosystem Interactions - Niche
 Organisms also have a niche.
 A niche is the role an organism has in its environment
 It is how the species meets its specific needs for food and shelter.
 It is how and where the species survives and reproduces.
Community Interactions
 Organisms living in biological communities interact
constantly.
 Each organism depends on other organisms and
competes with other organisms.
Competition
Predation
Symbiosis
 Competition occurs when organisms need to use the
same resource at the same time.
 It is for food, water, space, and/or light.
 When strong organisms compete with weak organisms,
the strong organisms usually survive.
 It is the act of one organism consuming another organism for food
 Most organisms obtain their food by eating other organisms.
 The organism that pursues is the predator.
 The organism that is pursued is the prey.
 Some species survive because of relationships with other species
 A relationship in which two organisms live together in close
association is called symbiosis
Mutualism
Commensalism
Parasitism
A relationship between two
species that live together
and benefit t from each other
One organism is helped and the other
organism is not harmed or helped
One organism benefits
and another organism is
harmed
CLASSWORK/HOMEWORK
 2.1 Reading Notes (Tuesday, April 22)
 2.1 Study Guide (Tuesday, April 22)
 How Does Your Biome Grow LAB
 2.1 QUIZ , Wednesday, April 23
Possible Biomes and Abiotic Factors
1)
2)
3)
4)
How does wavelength impact a biome
How does a type of soil impact a biome
How does wind impact a biome
How does CO2 level affect impact a biome