Unit 5
The Biosphere
Section 1 – Living Earth
A. Biosphere – the part of Earth that supports
life
1. The top portion of Earth’s crust, all
the waters on Earth’s surface, and
the surrounding atmosphere.
2. Made up of different environments
that are home to different kinds of
organisms
B. Ecosystem – all the organisms living in an area and
the nonliving features of their environment
1. Ecology is the study of interactions that occur
among organisms and their environment.
2. A population is made up of all the organisms
in an ecosystem that belong to the same species.
3. A community is all the populations in an
ecosystem.
Biotic vs. Abiotic
• Biotic: Features of the
environment that are
ALIVE, or were once
alive.
• Abiotic: The
NONLIVING, physical
features of the
environment.
C. Habitat – the place in which an organism
lives
1. Must provide the kinds of food,
shelter, temperature, and moisture
the organism needs to survive
2. Example: trees are the woodpecker’s
habitat
Section 2 - Populations
A. Competition – two or more organisms seek
the same resource at the same time
1. Competition of food, living space, or
other resources can limit the population.
2. Competition is usually most intense
between members of the same species.
B. Population size – indicates whether a
population is healthy and growing
1. Population density – the size of a population
that occupies a specific area
2. Two ways to measure the size of a wildlife
population
a. Trap-mark-release method
b. Sample count method
3. Elements that affect population size
a. Limiting factor – any living or nonliving
feature that restricts the number of individuals
in a population
b. Carrying capacity – the largest number of
individuals of one species that an ecosystem
can support
c. biotic potential – the maximum number of
offspring that parent organisms can produce
d. birth and death rates
e. movement or organisms into or out of an area
C. Exponential growth – the larger a
population becomes, the faster it grows
Section 3 –
Interactions Within Communities
A. Sun – source of energy that fuels most life on
Earth
1. Producers – organisms that use an outside
energy source to make energy-rich molecules
a. Most producers use the Sun and contain
chlorophyll, a chemical required for
photosynthesis
b. Some producers, found near volcanic vents on
the ocean floor, use mineral molecules as
energy sources for chemosynthesis.
2. Consumers – organisms that cannot make their
own energy-rich molecules; they obtain energy
by eating other organisms.
a. Herbivores, like deer and rabbits, eat plants.
b. Carnivores, like frogs and lions, eat animals
c. Omnivores, like pigs and humans, eat both
plants and animals.
d. Decomposers, like earthworms and
bacteria, eat dead organisms.
3. Food chain – a model that shows the feeding
relationships among the organisms in an
ecosystem
B. Symbiosis – any close relationship between
species
1. Mutualism – a symbiotic relationship in
which both species benefit
2. Commensalisms – a symbiotic
relationship in which one organism
benefits and the other is not affected
3. Parasitism – a symbiotic relationship in
which one organism benefits and the
other is harmed
C. Niche – an organisms role: a species’ unique
requirements for survival, including its habitat
and food, and how it avoids danger, finds a
mate and cares for its young
1. Predator and prey
a. Predator – consumer that captures and
eats other consumers
b. prey – the organism that is eaten
c. Predators limit the size of prey
populations, increasing the number
of different species that can live in
an ecosystem
2. Cooperative actions improve a species’
survival.
a. Example: one deer warns the other of
predators in the area.
b. Example: individual ants perform
different tasks required for the survival of
all.
Land Biomes
Information to Know
A. Factors that affect biomes climate
1. Temperature
2. Precipitation
B. Major biomes – large areas with similar
climates and ecosystems
Major Biomes
1. Tundra – cold, dry, treeless region
1. Permanently frozen soil called permafrost
2. Average winter temperature: -12˚C
3. Average precipitation is less than 25 cm a
year
4. Plants: mosses, grasses, small shrubs,
lichens
5. Animals: insects, ducks, geese, other birds,
,mice, arctic hares, reindeer
Tundra
Major Biomes
2. Taiga – cold forest of mostly evergreen
trees
a. Soil thaws in the short summer
b. precipitation: mostly snow, 35cm – 100
cm per year
Taiga
Major Biomes
3. Temperate Deciduous Forests – region
with four seasons, mostly trees that lose
their leaves in the autumn.
a. Temperatures range from below
freezing in winter to 30˚C or more in
summer.
b. Precipitation: throughout the year, 75cm
– 150cm per year
Temperate Deciduous Forest
Major Biomes
4. Temperate Rain Forest – tall tress with
needlelike leaves
a. Average temp: 9˚C - 12˚C
b. Precipitation: 200cm – 400cm per year
Temperate Rain Forest
Major Biomes
5. Tropical Rain Forest – the most
biologically diverse of all biomes
a. Average temp: 25˚C
b. Precipitation: 200cm – 600cm per year
c. Four zones: forest floor, understory,
canopy, emergents
d. Human Impact: Habitats being
destroyed by farmers and loggers
Tropical Rain Forest
Major Biomes
6. Desert – driest biome, supports little plant
life
a. Temp: vary from hot to cold
b. Precipitation: less than 25cm per year
c. Soil: thin, sandy, or gravelly
d. Plants: cactus
e. Animal: Kangaroo rat
Desert
Major Biomes
7. Grasslands – prairies or plains,
dominated by grasses
a. Temp: temperate or tropical
b. Precipitation: 25cm – 75cm per year;
dry season
Grassland
Aquatic Biomes
Section 3: Aquatic Ecosystems
A. Freshwater ecosystems – include flowing
and standing water, low or no salt
1. Rivers and streams – flowing water
a. Most nutrients washed into water from land.
b. The faster the flow, the greater the oxygen
content.
2. Lakes and ponds – very little flow
a. Sunlight warms and lights pond bottom,
supporting plant and animal life.
b. Deeper lakes support life along shallow
shoreline or surface.
3. Water pollution – a problem caused by
fertilizer – filler runoff and sewage
4. Wetlands – regions wet all or most of the
year.
a. Lie between solid land and water
b. Very fertile ecosystems
B. Salt water ecosystems – 95% of Earth’s
water contains high concentration of salt,
or high salinity.
1.) Open oceans – divided into lighted and
dark life zones
a. lighted – upper 200m and home of
plankton
b. dark – below 200m where animals feed
on material that floats down or prey on
each other.
2. Coral Reefs – diverse
and fragile
ecosystems formed
from coral shells of
calcium carbonate.
3. Seashores – along coastlines
a. Intertidal zone – covered with water at
high tide and exposed to air at low tide.
b. Drastic changes in temperature,
moisture, salinity, and wave action
4. Estuaries – where a river meets an
ocean; called bays, lagoons, harbors,
inlets, sounds
a. Rich in nutrients
b. Changing mixture of salt water and
freshwater.