Download 2-Principles of Ecology (notes)

Chapter 2 – Ecology
I.
Ecology - the study of interactions that take place
between organisms and their environment
 This
wildfire
affects plants,
animals, and
humans living in
this area
A.
The Environment is made up of Biotic
and Abiotic Factors
1.
Biotic Factors – living parts of the
environment
Bacteria (our gut)
Plants (cotton)
Fungi (mushroom)
Protists (algae)
Animals (bobcat)
Food production
(mg of glucose/hr)
2.
Abiotic Factors – nonliving parts
of the environment
 air, temperature, light, minerals,
water, soil
Food Production in Salt Bush
15
10
5
10
20
30
40
50
Temperature (°C)
 This graph shows how the plant’s food
production is affected by temperature
II.
Ecologists have organized the living world into
levels—the organism by itself, populations,
communities, ecosystems, biomes, & the
biosphere
A.
Organism – an individual living thing
1 antelope
B.
Population – a group of organisms (all of
the same species) which interbreed and
live in the same area at the same time
1.
They compete with each other for
food, water, mates, or resources
a group of antelope
C.
Community - made up of several different
interacting populations in a certain area
at a certain time
antelope
and zebras
1.
Different popns. may or may not
compete for the same resources
2.
Predation – some organisms pursue
others for food (prey)
D.
Ecosystem – biotic factors that interact
with each other in a given area and with
the abiotic factors of that area
antelope, kudu, water, air, trees
E.
Biome – large group of ecosystems that
share the same climate & have similar
types of communities
F.
Biosphere - the portion of Earth that
supports living things; made of all the
biomes
1.
It extends from the atmosphere to
the bottom of the oceans
 No life in the mantle
or core, inside the earth
III.
Types of Ecosystems
A.
Terrestrial – located on land
forest
old farm field
volcano
rotting log
B.
Aquatic – freshwater and saltwater forms
1.
pond
Freshwater Ecosystems:
stream
2.
lake
Saltwater/Marine
Ecosystems:
oceans,
estuaries,
aquariums
C.
Other Ecosystems
digestive system
mold in walls
skin
refrigerator
IV.
Organisms in Ecosystems
A.
Habitat - the place where an organism
lives out its life (its address)
B.
Niche - the role or position a species has
in its environment (its profession);
includes how it gets its energy
(autotroph or heterotroph)
Example: an oak leaf
 Habitat – a forest
 Niche – absorb sun, make food,
provide shelter for animals, etc.
C.
Symbiosis – a close relationship between
2 species; 3 kinds
1.
Mutualism - both species benefit
(+/+)
A grouper fish gets its mouth cleaned by a goby fish,
the goby fish gets food from the grouper’s mouth
2.
Commensalism – 1 species
benefits, other is neither helped nor
harmed (+/0)
 the clown fish gets shelter, the sea
anemone is not helped or harmed
3.
Parasitism – 1 species benefits,
other is harmed (+/-)
 a tapeworm weakens a
cow, but doesn’t kill it
V.
Nutrition & Energy Flow
A.
Food Chain – route showing how energy
flows through autotrophs, heterotrophs, &
eventually decomposers in an ecosystem
1.
2.
3.
Arrows show the
direction of energy flow:
plant → grasshopper
→ mouse → snake
Decomposers can break
down organisms at any
trophic level
Usually consists of 2, 3,
or 4 transfers
B.
C.
Trophic Levels – each feeding step in a
food chain or food web
1.
1st order heterotroph - feeds on
plants (grasshopper)
2.
2nd order heterotroph – feeds on
1st order heterotroph (mouse)
3.
3rd order heterotroph – feeds on
2nd order heterotroph (snake)
Food Web – model showing the many
interconnected food chains & routes in
which energy flows through a community
Food Chain song
Ecosystem Ecology (CrashCourse)
D.
Pyramids
1.
Energy, Biomass, & Numbers in each
transfer is less than the level before –
some energy is used to make new cells or
fuel the organisms at that level, some is
lost as heat (a byproduct of metabolism)