Introduction to EvolutionIntroduction to Evolution

Chapter 15

DO NOW !!!DO NOW !!!

What is the connection between the words EVOLUTION AND REVOLUTION

What is Evolution ???What is Evolution ???

Evolution is “change over time”

It is the process by which modern organisms have descended from ancient

organisms

What is a TheoryWhat is a Theory

A well supported testable explanation of a phenomena that have occurred in the natural world

We are going to discuss and learn about the Theory of Evolution

Charles DarwinCharles Darwin

“Father of Evolution”

Set sail on the H.M.S Beagle from England all around the world, especially the Galapagos Islands

He made numerous observations during his travels

                        

                                                                                          

Darwin’s Observation’sDarwin’s Observation’s

DIVERSITY !!!!!!Living organisms and FossilsAmongst the Galapagos Islands

Darwin noted that there were difference in climate, vegetation, and varieties in plant and animal types

Inferring in GroupsInferring in Groups

Make inferences about what particular species of animals need to survive in the Galapagos Islands

** Remember it’s not only their PHYSICAL characteristics of any organisms that make it survive but also its behavior and relationship with its environment

Darwin Presents His CaseDarwin Presents His Case

On the Origin of Species On the Origin of Species

Darwin summarizes 6 main points #1 OVERPRODUCTION –most species produce

far more offspring than are needed to maintain the population

#2 COMPETITION – since living space and food are limited, offspring in each generation must compete. Only a small fraction survive long enough to reproduce

Main Points (continued)Main Points (continued)

#3 VARIATION - The characteristics of the individuals in any species are NOT exactly alike. They may differ in the exact size or shape of a body, in strength, and in speed. These differences are called VARIATIONS. Others may affect the individual’s ability to get food, to escape enemies, or to find a mate.

#4 ADAPTATIONS –Because of variations, some individuals will be better adapted to survive and reproduce than others. In competition for existence, the individuals that have favorable adaptations to their environment will have a greater chance of living long enough to reproduce. An adaptation is any kind of inherited trait that improves an organism’s chance of survival and reproducing

#5 NATURAL SELECTION - “ Nature selects the survivors”. Individuals with variations that make them better adapted to their environment survive and reproduce in greater numbers than without such adaptations.

#6 SPECIATION –Over many generations, favorable adaptations gradually accumulated changes become so great that the net result is a new species.

Natural Variation VS Artificial Natural Variation VS Artificial SelectionSelection

According to Darwin, natural selection is the differences among individuals in a species Naturally.

In artificial selection, nature provided the variation among different organisms , and HUMANS selected those variations they found useful.

The Struggle for ExistenceThe Struggle for Existence

Each member of a species must compete regularly to obtain food, living space, and other necessities for life.

Those prey that are faster, better camouflaged, or better protected can avoid being caught.

Survival of the FittestSurvival of the Fittest

FITNESS – is the ability of an organism to survive and reproduce

Individuals the are better adapted or MORE FIT are more apt to survive

Evolution of PopulationsEvolution of Populations

Over time, it is a population that evolves not an individual organism

Descents with ModificationsDescents with Modifications

Each living species has descended, with changes, from other species over time

According to the principle known as common descent, all species-both living and extinct were derived from a common ancestor

Evidence of EvolutionEvidence of Evolution

Fossil records Geographic distribution of

living species Homologous Body

Structures- structures that have different mature forms but developed from the same embryonic development

Comparative AnatomyComparative Anatomy

Homologous structures have similar structures and similar embryological development but have different forms and functions ( example human hand, whale flipper)

Analogous structures have similar external forms and functions but different internal structures (example bird wing and insect wing)

Vestigial StructuresVestigial Structures

Structures that are remnants of structures that were functional in an ancestral form

In the human, wisdom teeth, the coccyx, and the appendix

Embryological SimilaritiesEmbryological Similarities

Many embryos look very similar during the early stages of development