Download Unit 6: Adaptation and Change

Unit 6: Adaptation and
Change
In this unit, we will explore how populations change
over time to survive in their environments, and what
happens when the environment changes.
Lesson 1: Change Over
Time
This lesson will explore how species change over
time in response to different factors.
Why so many dogs?
 New breeds of dogs develop over time.
When dogs with different traits mate and
produce offspring, some of the traits are
passed on to the next generation. These
traits can be physical, such as body size,
tail length, and fur color, or they can be
part of a dog’s personality, such as a
talent for hunting or herding. After many
generations, the accumulation of new
traits creates new breeds of dogs.
Humans Affect Species
 Throughout history, humans have bred different
dogs with favorable traits. This breeding has
gradually led to many different dog breeds with a
wide range of traits.
 New breeds of dogs develop over time. When dogs
with different traits mate and produce offspring,
some of the traits are passed on to the next
generation. These traits can be physical, such as
body size, tail length, and fur color, or they can be
part of a dog’s personality, such as a talent for
hunting or herding. After many generations, the
accumulation of new traits creates new breeds of
dogs
Changes in Plants
 Plants can change over time.
 Corn is a species of plant that originated in the
Americas. As corn spread to new cultures, humans
discovered new uses for corn.
 They selected the types of corn with traits that fit their
purpose, and grew corn from kernels, or seeds, that had
those traits.
 Humans use different varieties of corn for feeding
animals, making flour, eating off the cob, and popping.
Nature Affects Species
Changes in the environment are often the cause of
changes in a population. You can see an examples of
this changes:
 Certain plants(grasses) that grow near mines that
resist heavy metals
 Staphylococcus aureus resistance to penicillin
 House Sparrow body size
Lesson 2: Structural
Adaptations
In this lesson, we will look at a variety of examples of
physical structures of animals and plants that help them
survive in their environments.
Differing Traits
Organisms have different traits, both physical and
behavioral, that can increase their chances of
surviving and reproducing in one environment but not
in others.
These traits are called adaptations:
That’s why you don’t find polar bears and elephants
living by each other.
Why Adaptations?
To survive, individuals within it must meet 3 challenges of life:
 getting and using energy
 maintaining their structure
 Reproducing
To meet the challenges of life, an organism needs the right
“tools” for the job, and the job can change from one
environment to the next.
 Individual environments can also change over time,
requiring the populations living within them to change as
well.
 These changes occur when the individuals with undesirable
traits do not survive to reproduce.
 The offspring of the individuals that do survive to reproduce
will inherit their parent’s desirable traits.
 Over many generations, the desirable traits will be seen in
more—and sometimes all—of the individuals in the
population.
Tools for Getting Energy
Structural adaptations are an organism’s tools of
survival.
 What tools do animals use to meet the challenge of
getting and using energy?
 Some can use their eyes, ears, or noses to detect
food.
 Some animals need to chase and catch their food
 Some have specialized mouth structures or teeth
that are adapted for the kind of food they eat
These different birds have different sizes and
shapes of beaks. This allows the different
birds to take advantage of different types of
food. It reduces competition between them.
Tools for Maintaining
Structure
Organisms also need adaptations to protect and heal
their bodies—in other words, to maintain their
structure.
 Structural adaptations can help animals:
 Escape
 Defend themselves
 Hide from predators
 Make animals look dangerous, threatening, or badtasting.
 EX. shells or other hard coverings that protect
them from predators, bright warning colors, and
mimicry
Tools for Reproducing
Every species that exists today has inherited
structural adaptations that increase its chances of
reproducing.
 In the case of most animals, reproducing involves
selecting a mate.
 Although plants cannot actually search for a mate,
they have other ways of passing on their genes to
offspring.
 Ex. sweet scent of the lilac
Lesson 3: Behavioral
Adaptations
Behavioral Adaptations
Behavioral adaptations-traits that are part of
an organism’s inherited or learned
behaviors, or how it acts and what it does.
A behavior helps an organism respond to its
environment.
Behavioral Adaptations in
Animals
 Animals have acquired many kinds of behaviors that
help them survive.
 Learned Behaviors
 Innate Behaviors
 Learned behavior is determined by past experience, often
by observing others of the same species.
 Learned behaviors are those that organisms acquire through
experience
 Ex. Hunting Lion
 Innate behavior is inherited, genetically determined and is
built into an organism’s body.
 People call this type of behavior instinct.
 EX. Response to the color red by three-spined stickleback fish
Seasonal Changes
 Many behavioral adaptations allow animals
to respond to changes in their
environment.
 These adaptations allow them to survive if
the environment becomes too cold or dry,
or if food or nesting space become scarce.
 Many of these behaviors are associated
with the yearly change in seasons
Behavioral Adaptations in
Plants
There are many different ways a plant can respond to the
environment.
 Plants respond to light, gravity, and touch.
 Light: Most plants lean toward light, though a shadeloving seedling may lean to avoid direct sunlight.
 Gravity: Some parts of a plant move toward the center
of gravity. Roots display this movement by growing
down into the ground—or by growing down the edge of a
cliff on which the plant is growing.
 Touch: Plant vines often respond to touch. When a vine's
stem comes in contact with a tree trunk or other
supporting structure, the stem will curl around it. Other
plant parts, such as leaves, may also respond to touch
Lesson 4: Extinct or
Endangered?
What happens to a species when its environment
changes faster than the species can evolve?
Endangered species & The
End of a Species
All organisms have adaptations that help them survive in a
particular environment, but sometimes environments
change. Sometimes these changes can happen very fast.
 Endangered species-species at risk of disappearing
forever from the earth
 Extinct-no longer existing
Survival of a Species
 When an environment changes, the survival of a species
depends on the ability of enough individuals of that species
to survive in the new environment and reproduce.
 Some species, such as the giant panda and the dodo, are
not able to do this and become endangered or extinct.
 Others survive because they have traits that allow them to
survive in the new environment. When these species
reproduce, their offspring inherit these traits.
 Changes to the environment may affect some members of a
species, but others may survive.
 If the climate suddenly became colder, individuals with
thinner fur might die but individuals with thicker fur might
live, and the species would survive
Lesson 5: Changes in
Ecosystems
In this lesson, we will look at ways that ecosystems
can change and some effects of those changes.
Biotic & Abiotic Environments
 An ecosystem is made up of living things and the
physical environment in which they live.
 The living things in an ecosystem make up the biotic
environment. Introduction of a new species is an
example of a biotic change.
 The nonliving parts of an ecosystem, such as air, water,
and weather, are the abiotic environment. Air or water
pollution, drought, bad weather, or flooding are
examples of changes to the abiotic environment.
Changes and Their Effects
 Changes in an organism’s abiotic environment or biotic
environment can result in changes throughout the
ecosystem. The changes can be caused by natural
events or by human activity. The effects can be small or
large.
 K12 ex. Asian Tsunami-abiotic cause of environmental
change. Biotic changes occurred because of this abiotic
change.
Food Chains & Food Webs
Chains:
 Remember that all ecosystems are interrelated.
 All the organisms in an ecosystem depend on each other.
 Changes in one part of an ecosystem may affect other parts
of that ecosystem.
 One way to look at the ways organisms are connected in an
ecosystem is a food chain
Webs:
 Most ecosystems are more complex than a simple food
chain.
 Most consumers have more than one food source, and most
organisms can serve as a food source for more than one
organism. A food web shows this complex relationship.
 An ecosystem consists of many different food chains, each
operating at the same time. A food web is a complete set of
all the interconnected food chains
Impacts of Environmental
Changes
 Even small changes in an ecosystem can affect every
population in the ecosystem.
 The effect of the change on each organism depends on
the adaptations that organism possesses… adaptations
that help the organism survive in the new or changed
ecosystem.
 If enough individuals in a population have effective
adaptations and survive, the population will survive,
even if some individuals die.
 Environmental changes can be caused by natural events
or by human activity.
 The effects of environmental change can be barely
noticeable or they can be devastating.
Lesson 6: Rates of
Environmental Change
A change in the environment can be so slow that you
can hardly tell it is happening, or it can happen in the
blink of an eye. Let’s look at some of the environmental
changes that can affect an ecosystem.
Speed of Environmental Changes
Some environmental changes occur very quickly…like
sudden events or with natural disasters.
 Earthquakes, tsunamis, floods, volcanoes, and fires can
cause very rapid changes in ecosystems.
 Within minutes or hours, organisms may be faced with
new challenges.
 Those organisms with adaptations that help them
survive in the changed environment may survive, while
others may not
Weather and the Seasons
 Weather changes can be fast or slow.
 Many organisms have adaptations that help them
survive these seasonal changes.
 Seasonal changes include changes to the abiotic
environment, such as rainfall and temperature.
 Abiotic seasonal changes can result in changes in an
organism’s biotic environment.
Global Warming
 Most climate changes are very slow, but scientists have
determined that the average temperature on earth has
been rising for the last century.
 In the last 100 years, the average surface temperature
of the earth has risen by about one degree Fahrenheit
and could increase by another one to four degrees in the
next 50 years.
 This change may not sound like much, but compared to
normal climate change this is very fast.
 Most of this warming is likely due to human activity
Change Rates
Rapid Change
 The eruption of the Mount St. Helens volcano in 1980
caused a very fast change. Hot ash from the explosion
quickly killed all the organisms in the surrounding area
Slow Change
 After the eruption, the ecosystem began a slow change.
Seeds blew in on the wind, and some specialized grasses
and flowers were able to grow in the ash-covered soil and
bare rock. These plants broke down the ash and made the
soil more fertile so other plants could grow. As these plants
died, they added organic matter to the soil, improving it
even more. Eventually, more plants and animals moved to
the area.
 This type of change in an ecosystem is called
ecological succession.
Other Succession
 The type of slow environmental change known as
succession can also turn a pond into a meadow or a
meadow into a forest. During this natural process, some
populations increase, some decrease, and some disappear.
As the populations interact, they cause changes in the
ecosystem, allowing new populations to survive there