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 bad-tasting.

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 shade-loving 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 WebsChains:

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