Download Unit 21.1

Unit 21.1
Living Things and the Environment
Section 21.1
• Organisms obtain food, water, shelter, and
other things it needs to live, grow, and
reproduce from its environment.
• An environment that provides these things for
an organism is it’s habitat.
Biotic and Abiotic Factors
• The living parts of a habitat are called biotic
factors.
• The nonliving parts of the habitat are called
abiotic factors.
Biotic and Abiotic Factors
Fungi
Water
Oxygen
Berries
Sun
Plants
Worm
Prairie Dog
Hawk
Temperature
Soil
Bacteria
Biotic and Abiotic Factors
Fungi - Biotic
Water - Abiotic
Oxygen - Abiotic
Berries - Biotic
Sun - Abiotic
Plants - Biotic
Worm - Biotic
Prairie Dog - Biotic
Hawk - Biotic
Temperature
- Abiotic
Soil - Abiotic
Bacteria - Biotic
Levels of Organization
• All the members of one species living in a
particular area is a population.
• All of the different populations that live in an
area and interact make up a community.
• A community plus all of the abiotic factors in
that habitat make an ecosystem.
populations
not populations
communities
ecosystem
Levels of Organization
Levels of Organization
Levels of Organization
• The study of how living things interact with
each other and with their environment is
called ecology.
Studying Populations
section 21.2
Determining Population Size
1. Direct observation (count the organisms)
2. Indirect observation (look for signs of organisms)
3. Sampling (count the organisms in a small area and make
an estimate)
4. Mark and Recapture Studies (capture, mark, and
release organisms, then recapture and look for marks)
Studying Populations
Determining Population Size
Studying Populations
section 21.2
Changes in Population Size
• Populations can change in size when new
members join the population, or when
members leave the population.
Changes in Population Size
Births and Deaths
• The birth rate is the number of births in a
population in a certain amount of time.
• The death rate is the number of deaths in a
population in a certain amount of time.
If birth rate > death rate, population size increases.
If death rate > birth rate, population size decreases.
Changes in Population Size
Immigration and Emigration
• Immigration means moving into a population
• Emigration means leaving a population.
Population Density
•Population density is the number of individuals
in an area of a specific size.
Limiting Factors
• A limiting factor is an environmental condition
that causes a population to decrease.
1. Food and Water
2. Space
3. Weather
• The largest population that an area can
support is called carrying capacity.
Populations and carrying capacity
Interactions among Living Things
Section 21.3
• Remember: Because of natural selection
every organism has a variety of adaptations
that are suited to it’s specific living conditions.
• The role of an organism in it’s habitat is called
its niche. (what it eats, how it gets the food, what eats it, how and
when it reproduces, physical conditions it needs to survive)
3 Interactions among Living Things
Section 21.3
1. Competition
• Competition is the struggle between
organisms to survive as they attempt to use
the same limited resources.
3 Interactions among Living Things
Section 21.3
2. Predation
• Predation is an interaction in which one
organism kills another organism for food.
• Predators have adaptations that help them catch prey.
• Prey have adaptations that help them avoid being killed by
predators.
3 Interactions among Living Things
Section 21.3
3. Symbiosis
Commensalism
One organism benefits
while the other is not
harmed.
Mutualism
Both organisms benefit.
Parasitism
One organism
benefits and the
other is harmed.
Energy Flow in Ecosystems
Section 22.1
• Each of the organisms in an ecosystem fills the
role of producer, consumer, or decomposer.
Energy Flow in Ecosystems
Section 22.1
Producers
• An organism that can make its own food is a
producer. They are the source of all the food
in an ecosystem.
Energy Flow in Ecosystems
Section 22.1
Consumer
• An organism that obtains energy by feeding on
other organisms is a consumer.
• Consumers can be carnivores, herbivores, or
omnivores.
Carnivores
Consumers
Herbivores
Consumers
Omnivore
Consumers
Energy Flow in Ecosystems
Section 22.1
Decomposer
• An organism that breaks down waste and
dead organisms and returns the raw materials
to the environment is a decomposer.
Food Chains and Food Webs
• A food chain is a series of events in which one
organism eats another and obtains energy.
• A food web consists of the many overlapping
food chains in a particular ecosystem.
Energy Pyramid
• An energy pyramid shows the amount of
energy that moves from one feeding level to
another in the food web.
• The most energy is available at the producer
level of the pyramid. As you move up the
pyramid, each level has less energy available
than the level below.
Changes in Communities
Section 21.4
• The series of predictable changes that occur in
a community over time is called succession.
Changes in Communities
Section 21.4
• Primary Succession is the series of changes
that occur in an area where no soil or
organisms exist.
• The first species to populate an area are called
the pioneer species.
Changes in Communities
Section 21.4
• Secondary Succession occurs in a place where
an ecosystem currently exists.
Changes in Communities
Section 21.4
• Lichens are compound creatures, formed from
the symbiotic relationship between a algae
and a fungus.
• They grow on rocks, tree trunks and branches.
Changes in Communities
Section 21.4
• When lichens die they create a weak acid that
eats away at the rock, creating a soil where
mosses can grow and in time larger bushes.
• Lichen are pioneer plants in succession.
Primary or Secondary
Succession?
State whether they are primary or secondary succession and HOW
YOU KNOW:
Cycles of Matter
Section 22.2
The Water Cycle
• The processes of evaporation, condensation
and precipitation make up the water cycle.
The Water Cycle
Cycles of Matter
Section 22.2
The Carbon and Oxygen Cycle
• The carbon and oxygen cycle traces the way
producers, consumers, and decomposers each
play a role in the linked recycling of carbon
and oxygen in ecosystems.
The Carbon and Oxygen Cycle
Cycles of Matter
Section 22.2
The Nitrogen Cycle
• In the nitrogen cycle, nitrogen moves from the
air to the soil, into living things, and back into
the air.
The Nitrogen Cycle
Freshwater Ecosystems
• Freshwater ecosystems include streams, rivers
ponds and lakes.
Streams and Rivers
• Water currents flow strongest in streams
which flow and join together forming larger,
but slower moving rivers.
Ponds and Lakes
• Ponds are smaller bodies of still water where
light can often reach the bottom.
• Lakes are generally larger than ponds and the
water temperature varies between the top
and the bottom depending on the season.
Freshwater Ecosystems
Organisms Adaptations
Freshwater Ecosystems
Organisms Adaptations
Adaptations:
• After reading about the organisms found in
freshwater ecosystems explain what types of
organisms are found in each environment, and
what adaptations make them well suited for
that environment.
• Scavenger – a consumer that eats dead
organisms
• Primary consumer – the first consumer in a
food chain (eats a producer)
• Secondary Consumer – the second consumer
in a food chain (eats a primary consumer)
• Climax community – a fully established
(developed) ecosystem after succession.
BIOMES
• A biome is a group of land ecosystems with
similar climates and organisms.
• It is mostly the climate (temperature and
precipitation) that determines its biome.
(That is because the types of organisms that can live in an area
depends a lot on the climate.)
BIOMES
There are 7 major biomes that most ecologists study:
1. Tundra
BIOMES
There are 7 major biomes that most ecologists study:
2. Rainforest
Temperate Rainforest
Tropical Rainforest
BIOMES
There are 7 major biomes that most ecologists study:
3. Deciduous Forest
BIOMES
There are 7 major biomes that most ecologists study:
4.Taiga (boreal forest)
BIOMES
There are 7 major biomes that most ecologists study:
5. Grassland (savannah)
BIOMES
There are 7 major biomes that most ecologists study:
6. Desert
BIOMES
There are 7 major biomes that most ecologists study:
7 and 8. Aquatic Biome
Marine
Freshwater