TAKS OBJECTIVE 3 TEKS OBJECTIVE

7(B)NATURAL SELECTION AS A PROCESS OF

EVOLUTIONThe student knows the theory of

biological evolution. The student is expected to (B) illustrate the results of

natural selection in speciation, diversity, adaptation, behavior, and extinction.

Focus Question: Discuss and record your answer in your packet. Explain how changes in an environment

may change a population of organisms.

TAKS Practice: Characteristics of Some Lizards

Which of the following is supported by the information shown above?

F These lizards evolved in arid habitats.G Modern lizards drink more water than their ancestors.H These lizards cool themselves by evaporation.J Modern lizards excrete more water than their ancestors.

•Live mainly in hot, dry climates•Release very little water•Excrete wastes in the form of solid uric acid, which contains very little water.

Common Descent with Modification Natural Selection

is THE driving force of evolution

During the struggle for resources only the strongest will survive & reproduce.

What happens to those that aren’t the strongest???

Consider this situation… The idea that

organisms change with time, diverging from a common ancestor caused evolution of new species

What will happen to the descendents of #2 when the same insecticide is used?

What will happen to the genes of those killed by the insecticide?

If You Can't Run You've Got to Hide! Where’s Waldo???

What if you aren’t the fastest or strongest?

Physical Adaptations: CAN YOU FIND THE US?

Adapt to the

environment

Behavioral adaptations for survival

SOLITARY

SCHOOL

HERD

Think about how each of these behaviors might help an organism survive?

Is there safety in numbers? Why would some sharks be solitary?

Speciation: all of these finches descended from a common ancestor

Each of these modern finches has found a specific niche to survive in based on its beak shape and size. Leads to

biodiversity in nature

Natural variation in one plant species

EXPLANATION NECESSARY VOCABULARY:

Evolution – Biodiversity – Natural Selection – Survival of the Fittest – Speciation – Behavior – Adaptation – Extinction -

Evolution Change over time

Biodiversity The vast assortment of life forms on earth

Natural Selection The survival and reproduction of organisms that have inherited the most desirable characteristics.

Survival of the Fittest Organisms that are fit for that environment will survive &

reproduce.

Speciation The formation of new species resulting from reproductive isolation.

Behavior The way an organism reacts to changes in its internal or external

environment.

Adaptation Ability to adjust to new environment.

Extinction Cessation of existence of a species or group of taxa.

The guppy is a species of small freshwater fish. Scientists observed that the average size of guppies in a pond decreased over a few years after a guppy predator was introduced into the pond. Which of the following best explains the change in guppy size?

F SpeciationG Convergent EvolutionH Inbreeding J Natural Selection

Birds and reptiles are similar in that they are vertebrates and lay eggs. They differ in that reptiles have teeth and birds have beaks. Some birds do possess teeth. However, these teeth are present only in the embryonic stage. Which conclusion is best supported by the presence of teeth in bird embryos?

A Birds and reptiles share a common ancestor

B Modern reptiles are the ancestors of modern birds

C Birds and reptiles eat similar types of foodD Ancestors of reptiles had beaks similar to

that of birds

Because of this animal’s adaptations, it would be most successful at —

F competing with birdsG making its own foodH hiding from predatorsJ running very rapidly

The diagram illustrates how some characteristics of the horse have changed over time. Along with the difference in size, what is another anatomical difference between the modern horse and its ancestors?

A. The structure of the tooth has been adapted for eating meat.

B. The size of the molars has decreased.C. The length of the forefoot has decreased.D. The number of toes has decreased.

The maps below show the geographic ranges of four species of the order Lagomorpha, which includes rabbits and hares. In which range would developing white fur in winter most likely not be an advantage for a member of this order?

What I need to remember… Write down the 3 most important things

about this topic.