Principles of Ecology
Chapters 3, 4, 5, & 6
What is Ecology?
• Ecology is the study of interactions between
organisms and their environment.
Components of the Biosphere
1. Biosphere – portion of the Earth
supporting life
Within the biosphere you
have the following
factors:
A. Biotic factors
1. All organisms inhabiting the environment
2. The “living” things in the environment!
B. Abiotic factors
1. Nonliving parts of the environment
2. Can determine which species will survive
examples: rainfall, temperature, light, soil
Rain, Rain
Go Away…
C. Levels of Biological Organization
1. Species: a group of organisms that can
breed and produce
fertile offspring!
2. Populations
-A group of organisms of the
same species living together
-Must compete for resources
Levels of Biological Organization
3. Community
a. Several populations that
interact
b. Changes in one population will
cause changes in the others
4. Ecosystem
a. Interactions between
populations and their
surroundings
b. 2 main types
1. Terrestrial – land
2. Aquatic – fresh or salt water
D. Niche vs. Habitat
1. Niche
*The role an organism plays in the
environment
*(Its “job” in the community)
2. Habitat
*Place where an organism lives
Habitat of the
earthworm: SOIL
Niche: To aerate
(break-up) the soil.
Types of Feeding Relationships
1. Autotrophs
a. Self-feeders, produce their
own food
b. Example: plants, algae
2. Heterotrophs
a. Depend on other organisms
for food
Herbivore – eats only plants
Carnivore – eats only meat
Omnivore – eats both
3. Decomposers
a. Break down and absorb nutrients
from dead organisms
b. Example: mushrooms, bacteria
bacteria
fungus
mushroom
earthworms
4. Symbiosis - close, permanent
relationship between organisms
a. Three major types:
1. Commensalism
2. Mutualism
3. Parasitism
2) Friend alga cell is prepared to
greet Mr. Fungus
1) Mr. Fungus is ready to greet our friend the alga
3) The Lichen is created between the fungus and the alga
1. Commensalism
a. Relationship in which one species benefits
and the other is not affected
b. Example: remoras that live on/around a
shark’s mouth
Remora
on a Ray
tickbirds
2. Mutualism
•
a. Both species benefit
b. Example: tickbirds
eat parasites off of a
rhino
oxpeckers
3. Parasitism
•
a. One organism
benefits and the
other is harmed
b. Example: tapeworm
living inside a
person’s intestine
o Energy pyramids:
show decreasing
amounts of energy,
biomass, and number of
individuals as you
move up the pyramid
There is no limit to the number of levels that a food
chain can support. Only 10% of the energy from one
level is transferred to organisms at the next level. *The
remaining energy is released into the environment as
heat.
Food Chains and Food Webs
1. Food Chains
a. Model showing
movement of
energy through
the ecosystem
b. Uses arrows to
show “what
eats what”
Food Chain
Grass  Cow  Human
2. Food Web
a. More complicated
than a food chain
b. Shows more than
one food
source for each
organism
c. More realistic view
of energy
transfer
Quiz 1
1. Your house is an example of a(n) ___.
a. biotic factor
b. habitat
c. niche
2. Trees, mosses and shrubs are all examples of what type
of factor?
a. abiotic
b. biotic
c. commensalism
3. The study of interactions between organisms and their
environments is called ?
a. botany
b. cytology
c. ecology
4. If you work at McDonald’s, that is an example of your?
a. habitat
b. niche
c. community
5. A group of deer that live in a forest is an example of a?
a. biosphere
b. community
c. population