Unit 3 Notes
Chapter 4: Ecosystems and Communities
Review from Unit 2:
1. ________________________: groups of organisms that are similar enough to breed
and produce fertile offspring
2. ____________________________: groups of organisms of the same species living in
a particular place
3. ____________________________: group of organisms of different species living in a
particular place (includes all living things—plants and animals)
4. ____________________________: all of the living AND nonliving things in a
particular area
 Example: plants, animals, water, climate, soil, rocks, etc.
5. ________________________: group of ecosystems with the same climate and similar
communities
 Example: Desert, Tundra, Savanna, Tropical Rainforest
6. ____________________________: area on earth where all life exists
Chapter 4:
I.
The Role of Climate
a. Two major factors affecting ecosystems and biomes are
________________________ and _________________________.
b. Temperature, precipitation, and other environmental factors combine to produce
weather and climate.
c. What is the difference?
d. Climate vs. Weather
i. ___________________________ = day-to-day conditions in an area
 Example: Is it raining? Is it sunny or cloudy? Is it windy? Is it foggy?
ii. __________________________ = average yearly conditions of
temperature and precipitation in a region
 Example: What is the average yearly temperature? Are there different
seasons? What is the average yearly humidity and precipitation?
II.
Factors that Contribute to Climate
a. _________________________ of heat by the atmosphere
b. Transport of heat by _____________ and __________________ currents
c. Amount of precipitation
III.
IV.
V.
VI.
d. _________________________ (how far north or south a place is)
The Effect of Latitude on Climate
a. Earth is a sphere tilted on its _____________ and receives sunlight at different
angles throughout the year
b. Different latitudes = different angles of heating by the sun
c. Creates 3 Climate Zones:
i. ___________________: cold and dry; sun’s rays hit at low angles
ii. ________________________: between polar and tropical; most changes
in light; temperature varies from hot to cold
iii. ______________________: near equator; direct or nearly direct light year
around; hot and wet
The Greenhouse Effect
a. _________________ in the atmosphere (H2O, Co2, and methane) trap heat and
warm the earth.
Heat Transfer in the Biosphere
a. Heat is moved by _______________ and air currents
b. __________________ air/water rises and _______________ air/water moves in.
This creates currents.
What Shapes an Ecosystem?
a. Ecosystems are influenced by ______________________ and
___________________ factors.
b. Biotic factors = ___________________ (biological) influences on an organism
c. Abiotic factors = ____________________ (physical) influences on an organism
d. ____________________ = the biotic and abiotic factors where an organism lives
i. Habitat is like an organisms _______________________
e. ____________________ = all biotic and abiotic factors where an organism lives
AND the way in which it uses those factors
i. Niche includes WHERE an organism lives PLUS things like…
 What it eats? Any predators? Where in the habitat does it live…tree,
pond, underground?
 The organisms actions…hibernating, migrating, when and how it
reproduces?
f. Habitat vs. Niche
i. Habitat is like the organism’s ________________________.
ii. Niche is like the organism’s _________________________.
g. ____________________________ = anything needed by an organism for life
i. Examples: Nutrients, water, light, space
VII.
Community Interactions
a. There are several ways species interact with each other:
i. Competition
ii. Predation
iii. Cooperation
iv. Symbiosis
b. Competition = between ________________ or ____________________
species
i. Compete with each other for available resources
ii. Organisms in an ecosystem have to compete with each other for
available _______________________ such as…
 FOOD
 SHELTER
 MATES
 SPACE/TERRITORY
 LIGHT (especially plants!!)
iii. If resources are _____________________, some organisms will starve
and populations will _______________________.
iv. If resources become more _______________________, populations will
________________________.
v. Competition in nature often results in a winner and a loser…with the loser
failing to survive!
vi. If a nutrient is in short supply OR cycles slowly through the ecosystem, it
will __________________ the growth of a population. This is called a
_____________________ FACTOR (or limiting nutrient).
vii. Limiting Nutrient
 The short supply of a limiting nutrient keeps the population in check.
 When an ecosystem receives a LARGE input of limiting nutrient (Ex.
Fertilizer) the population __________________ dramatically.
 Example: Algal bloom
c. Predation = between _______________________ kinds of organisms
i. ______________________ = organism that hunts and kills other
organisms to supply their energy needs
ii. ______________________ = organisms in an ecosystem that get eaten
by a predator
d. Cooperation = between ______________ kind of organisms
i. Live together and _________________ each other
 Example: Monkeys helping clean each other.
ii. Same species live together in groups
 Example: herds, packs, colonies, families
 Share food and childcare responsibilities
 Groom each other
 Take care of sick
 Hunt in packs
 Provide protection
b. Symbiosis = between ____________________ species; two species living
closely together
i. 3 Types of Symbiosis:
 Mutualism
 Commensalism
 Parasitism
ii. Mutualism = both organisms ______________________
iii. Commensalism = one organism is helped; the other organism is
NEITHER ____________________ nor _____________________
iv. Parasitism = one organism benefits (the parasite); the other organism
(host) is _____________________ in some way
EXAMPLES OF SYMBIOSIS

Insects transfer pollen between plants as they gather nectar for food.
Insects: a. helped
b. harmed
c. neutral
Plants:
a. helped
b. harmed
c. neutral
Type of symbiosis: ____________________________________

Tapeworms absorb food by living inside a host’s intestine. The host is harmed.
Tapeworm:
a. helped
b. harmed
c. neutral
Host:
a. helped
b. harmed
c. neutral
Type of symbiosis: ____________________________________

Clownfish gets protection from enemies by hiding out in poisonous sea anemones.
Sea anemone gets scraps of leftover food dropped by fish.
Clown fish:
a. helped
b. harmed
c. neutral
Sea anemone:
a. helped
b. harmed
c. neutral
Type of symbiosis: ____________________________________

Hermit crabs make homes in shells abandoned by snails. Snail is not harmed by
crab.
Hermit crab:
a. helped
b. harmed
c. neutral
Snail:
a. helped
b. harmed
c. neutral
Type of symbiosis: ____________________________________

Birds eat parasites living on hides of giraffes and rhinos while enjoying protection
from predators. Groomed animals lose their pests.
Birds:
a. helped
b. harmed
c. neutral
Rhinos and Giraffes:
a. helped
b. harmed
c. neutral
Type of symbiosis: ____________________________________

Ticks are blood sucking insects that attach to a dog’s skin. The ticks feed on the
dog’s blood, and the dog has discomfort and can get diseases.
Tick:
a. helped
b. harmed
c. neutral
Dog:
a. helped
b. harmed
c. neutral
Type of symbiosis: ____________________________________

Pilot fish receive scraps of food dropped by shark. Shark is neither harmed nor
helped.
Pilot fish: a. helped
b. harmed
c. neutral
Shark:
a. helped
b. harmed
c. neutral
Type of symbiosis: ____________________________________