Download Organisms and Their Environment

Organisms and Their
Environment
Biology 2009
Environment and Ecology
Everything that surrounds a living thing
makes up its environment.
Living things are affected by their
environments, and also have an impact on
their environments.
The study of the interaction between
organisms and their environment is called
ecology.
Ecosystem
An ecosystem is composed of all living and
nonliving things in a particular location.
Examples:
 Forest
 Pond
 Meadow
 Any place where living things interact with the
nonliving environment.
Biotic Factors
The living things are called biotic factors
(bio = living)
Examples:
Microorganisms
Plants
Animals
Abiotic Factors
The nonliving things are called abiotic
factors.
Examples:
Climate
Soil
Rocks
Wind
Rain
Species
A biological species is a group of organisms
having a genetic makeup that is similar
enough that they can mate and produce
fertile offspring.
Populations
A population is made up of all members of a
particular species living in a particular area
at the same time.
Example:
All of the deer living on Kennesaw Mountain
Another Example:
All the ducks of a certain species living in a
pond would be a population. Within that
population, individual ducks may vary in
many traits, such as size. However, most
members of the duck population could be
described by an average size.
Community
All of the populations living in the
same area make up a community. It includes all
the different kinds of living things, which all live
together.
Example:
The frogs, lizards, birds, ducks, spiders,
mosquitoes, flies, etc., that live in your backyard.
Habitat
A habitat is the physical surroundings, or the
place, in which an organism lives.
Niche
A niche includes all aspects of an animal’s
lifestyle, especially its feeding patterns. A
niche also refers to the job or role that
each organism has in the community/
Animals that live in the same place, but do
not feed in the same way, do not fill the
same niche and do not compete with each
other.
Biosphere
The biosphere is the part of the Earth where
life exists. It consists of the thin envelope
around the Earth made up of atmosphere,
land and water. The biosphere has
elements that are constantly used and
reused in the ecosystems.
The Elements
The elements used and reused in the
biosphere are Carbon, Hydrogen, Oxygen
and Nitrogen. They are provided in cycles
so they can be used and then reformed to
keep the elements constant in our
environment.
Water Cycle
The water cycle provides water which is necessary
for organisms to live. Water evaporates from the
surface of Earth, whether from water sources or
moist land. As much as 2/3 of all precipitation
evaporates into the atmosphere. Water vapor
condenses and clouds form. Precipitation in the
form of snow, ice, or rain falls to the Earth.
Eventually that precipitation will again
evaporate.
Water Cycle
Nitrogen Cycle
The nitrogen cycle is needed to supply amino acids which
are the building blocks of proteins. Nitrogen gas is 80%
of our atmosphere. Some organisms can only use
nitrogen in the form of ammonia. When nitrogen in the
air is converted to ammonia it is called Nitrogen Fixation.
Some bacteria convert nitrogen on plant roots so that
nitrogen is eaten in the plant and the consumers use it to
make protein. Nitrogen is also found in our waste
products and in decaying matter. When organisms die,
decomposers return nitrogen to the soil.
Nitrogen Cycle
Carbon Cycle
The carbon cycle provides carbon, an element
present in every living organism. Carbon is in
our atmosphere in the form of carbon dioxide. In
organisms carbon dioxide is breathed out in
respiration and is released in the decomposition
of matter. Plants use carbon dioxide in
photosynthesis and make sugars and oxygen.
Carbon Cycle
Biomes of North America
Biomes are parts of the biosphere characterized by large
regions that can be identified by the types of plants and
animals that live there.
Biomes:
 Tundra
 Desert
 Grassland
 Tropical Rain Forest
 Temperate (Deciduous) Forest
 Taiga (Coniferous Forest)
Biomes
A number of climatic factors interact in
creating a biome.
Temperature
Precipitation
Length of growing season
Tundra
Regions – Arctic/Antarctic areas
Plant life – grass and wildflowers
Animal life – reindeer, caribou
Description – thin soil, permafrost
Taiga
Regions – Northern forests
Plant life – Conifers
Animal life – Wolves, rabbits, elk
Description – Long, cold winters
Deciduous Forest
Regions – NE/mideastern US; Western Europe
Plant life – Deciduous trees
Animal life – deer, birds, small animals, bears
Description – Avg. precipitation, warm summers,
cold winters
Grassland
Regions – Mid-western US; Eurasia, Africa
Plant life – Grasses
Animal life – Prairie dogs, ferrets, snakes
Description – Hot summers, cold winters,
rainfall unpredictable
Desert
Regions – Western US; N. and SW Africa
Plant life – Cacti, succulents
Animal life – Jackrabbits, lizards, rats
Description – Arid; extreme daily
temperatures
Tropical Rainforest
Regions – Central America, Central Africa,
SE Asia
Plant life – Diverse plants
Animal life – monkeys, leopards
Description – High rainfall and temperature
Changes in Populations
Ecological Succession
Populations of species found in certain
habitats change over time. This concept,
called ecological succession or
environmental variation.
Primary Succession
Primary succession consists of a sequence
of communities developing in a newly
exposed habitat devoid of life.
Examples:
Succession on a bare rock
Newly deposited sand
New land from cooled lava
Secondary Succession
Secondary succession consists of communities
taking place on sites that have already
supported life.
Examples:
 Old field succession
 Clearcut forests
 Burned areas
**Difference between primary and secondary succession
is that secondary starts with soil.
Pioneer Community
The original plant forms that colonize an area are
called the pioneer community.
These must be a strong group, able to withstand the
forces of mother nature.
**Bare rock would be an unwelcome habitat for most
plants, but lichens are up to the challenge. Blown
there by the wind, lichens attach to the rock and
begin the process of breaking it down as it carries
on its life functions. As soil accumulates, a bare field
forms. This eventually becomes the home of
grasses and flowers.
The Progression
1. Rock
2. Lichen
3. Soil
4. Grasses
8. Hardwood
Forest
5. Flowers
7. Pine Forest
6. Shrubs
Climax Community
A hardwood forest of trees like oak, beech,
and maple trees, grows in the final stage
of development. This final stage is called
the climax community. The climax
community does not change much, as
long as no disasters strike, like wild fires,
tornadoes, or humans needing a parking
lot!
Animals
The animals that live in the habitat change
as the plants change.
Small animals like mice and rabbits, prefer
the open field.
More Animals
Deer and bear prefer the cover of wooded
environments.
Ponds
Pioneer communities may sometimes be
ponds that develop underwater plants,
then cattails. As the pond fills with
sediment, grasses may begin to grow and
over many years, the succession
eventually results in a deciduous forest for
that area.
Succession vs. Evolution
**Ecological succession should not be confused
with evolution.
Succession involves organisms moving into and
out of an area over a period of time as a result of
environmental change.
Evolution involves changes in genetic makeup of a
species over generations, which may adapt the
animal to a particular environment.
Survival of the Fittest
One of the basic concepts of evolution is that
organisms compete for the available resources
in their environments: food, shelter, or mates.
Organisms that are more fit will be able to win
this competition. An animal that outperforms
others, such as running faster, locating food
better, or surviving more fights, will be more
likely to reach maturity and eventually produce
offspring. These traits will then be passed on to
succeeding generations. This is known as
survival of the fittest.
Geographic Isolation
Changes in population can also result from
geographic isolation. Geographic isolation
occurs when a population becomes separated
by changes in the environment.
In order for a species to exist in a changing
environment, members must adapt in order to
survive and reproduce.
If this does not occur, the species will become
extinct.
Responses and Behavior
One very important life function is that of response.
Response characteristics of cells enable
organisms to react to stimuli in their
environment.
A group of complex responses is called a
behavior.
A reflex is an involuntary response to
environmental stimuli.
An instinct is a genetically controlled behavior.
Examples
Reflex:
A person’s eye blinks as an object flies
past it.
A dog sneezes when it inhales pepper.
Instinct:
Birds respond to changes in season by
migrating.
A bee develops into a drone.
Tropism
Tropisms are examples of responses to
environmental change.
A tropism is an involuntary response of an
organism involving orientation toward or
away from external stimuli.
Geotropism
Plants respond to gravity by sending roots
“down.” It is called geotropism.
Phototropism
Phototropism adjusts plants exposure to
light.
Thigmotropism
Thigmotropism is a plant’s response to
touch.
Adaptation
Organisms which do not, or cannot respond to
changes in the environment reduce their
chances for surviving. This may mean death for
the individual organism and, in extreme cases,
extinction of the species if too many die before
they are able to reproduce.
Response to the environment is, therefore, closely
related to adaptation.
Adaptations
Adaptations allow one kind of organism to live in
conditions where other organisms cannot.
Examples:
 A cactus has special adaptations which allow it
to live in a dry, hot environment.
 Polar bears have adaptations which allow them
to live in very cold environments.
**The polar bear could not survive in the desert and the
cactus could not live in the Arctic.
Homeostasis
All organisms must have life functions which
work together to produce and maintain a
stable internal environment. This is the
principle of homeostasis.
Adaptations are made to produce
homeostasis.
Adaptation Example
Certain rabbits turn from brown to white in the
winter so they can be camouflaged with the
snow. Since rabbits with dark coats were more
easily seen, they were more likely eaten.
Gradually, the proportion of winter-white rabbits
to winter-dark rabbits would increase until there
were no dark rabbits left.
**This is known as survival of the fittest.
Human Example
In areas where there is a higher incidence of
malaria, there is also a higher incidence of
sickle cell anemia. This is because the
sickle shaped cells cannot be infected with
malaria. Over time, the people in the area
with sickle shaped red blood cells survived
because they were not catching malaria
and people with normally shaped red
blood cells were dying.
Food Chains and Food Webs
Predator and Prey Relationships
One important interaction in the ecosystem is
between predators and their prey.
Predators are organisms which hunt and feed on
other organisms.
The living things that are eaten are referred to as
prey.
**To maintain balance in the ecosystem, the
interaction between predator and prey should
not be disturbed.
Example
In parts of the South, one natural predator of
the white-tailed deer, the mountain lion,
has been reduced in number. Because
there are fewer mountain lions to prey on
the deer, the deer population in some
regions has risen tremendously.
Food Chain
A food chain is the relationship of organisms
that depend on each other for energy or
food.
It is a straight line relationship such as algae
is food for fish which are food for squid
which are food for sharks.
Food Web
A food web is more complex and is a food
chain with the interrelated chain of
organisms that depend on each other for
food.
If one organism is removed, other organisms
may be endangered or possibly die out.
Food Web
Carrying Capacity
Carrying capacity is the number of
individuals in a population that the
resources can support. This provides for a
balanced ecosystem.
Trophic Levels
The living things in an ecosystem can be
divided into four levels. Each step in a
food chain or food web is called a trophic
level.
Producers are the first step.
Consumers are the next steps.
Each step depends on the step below it for
food and to provide its energy.
Producers
Producers are the green plants and some
bacteria and alga that are able to make
their own food from water, the sun, carbon
dioxide in the air, and minerals in the soil.
**Remember when plants make their own
food they use sunlight and it is called
photosynthesis.
Consumers
Consumers are the animals that rely on other organisms for
food. This group can be further divided into three groups:
 Primary consumers are herbivores, or plant eaters.
Examples – certain insects, deer, or mice.
 Secondary consumers are carnivores, or flesh eaters.
They feed on herbivores. Examples – snakes and
coyotes
 Tertiary consumers can be carnivores or omnivores,
which eat both plants and animals. Example – hawks
and humans
Scavengers
Scavengers feed on dead organisms. They
include earthworms, ants and vultures.
Decomposers
Decomposers are organisms that break
down dead organic matter. This
decomposition produces many of the raw
materials that are used by the producers in
photosynthesis.
Decomposers include bacteria and fungi.
Ecological Pyramids
Ecological pyramids are diagrams that show
each trophic level in a biome. There are
three types:
Energy pyramid
Biomass pyramid
Numbers pyramid
Energy Pyramid
Energy pyramid – the energy pyramid shows
the transfer of energy from one level to the
next. The bottom of the food chain shows
the largest amount of energy which comes
from the sun then as you move up energy
is used but also lost in the form of heat
energy.
Energy Pyramid
Biomass Pyramid
Biomass pyramid – the biomass pyramid is
based on the mass of organic material at
each level.
Numbers Pyramid
Numbers pyramid – it shows the relative
numbers of organic material at each level.
1 organism
10 organisms
100 organisms
1000 organisms