Introduction to Evolution

Mr. Modafferi

Biology 9 - Regents

Do NowHow many recorded species are there in the

world?

1.4 Million Recorded

Interesting Fact

Hydrothermal vents along the floor provide a type of chemical energy for bacteria. These bacteria use this energy like plants use the energy of the sun. They then form the base of a giant food web thousands of feet below the surface. Only until recently have we been able to discover this new habitat. Now scientists believe there could be as many as a million species just in on the ocean floor.

How is it possible that there are so many different species? The Theory of Evolutionary

Evolution The genetic changes in organisms over time

This explains how modern organisms have descended from ancient organisms

Occurs in populations of organisms, not individuals

Evolution is one of the great unifying theories of biology

“Scientific” Theory Statements or models that have been tested

and confirmed many times THERE IS NO DOUBT IN THEORIES

Theory is almost as good as fact because it has been tested and retested by many people.

Properties of Theories They explain a wide variety of data and

observations They can be used to make predictions They are not absolute, they serve as a model

of understanding the world and can be changed as the world view changes

Question of the Day How did organisms change over time

(evolve)? How is a Giraffe’s neck longer now than it was in

the past?

Lamarck’s Hypothesis of Evolution

Lamarck (1744-1829)1)Believed that species would gain or lose

features if they overused or didn’t use them- They adapted to their environment

2)Inheritance of acquired characteristics- Lamarck believe that organisms become adapted to their environment during their lifetime and pass on these adaptations to their offspring

Use and Disuse - Explained New structures arise because they are needed Structures already present become better

developed due to frequent use Structures that are not used decrease in size

and eventually disappear

A giraffe stretched its neck to reach higher leaves, and this stretched neck would be a trait inherited by its offspring

Lamarck’s Theory Was Proven Wrong!

Think Logically If you had a terrible accident and one of your

limbs got amputated would your offspring not have that limb when born?

Who is the “main man” of evolution? Charles Darwin Born: February 12, 1809 The main contributor to the modern theory of

evolution He wrote The Origin of Species in 1859

Charles Darwin Darwin made many observation and collected

different specimens during his five-year journey on the Beagle.

Please take out your map of Darwin’s journey and lets discuss some of his observations!

Darwin's many observations led him to the idea that species slowly change over time

Darwin's comparison of the animals of South America and the Galapagos Islands caused him to conclude that adaptation to the environment can cause diversification, including origin of new species

Examples: Patagonian hares replaced rabbits in the South American grasslands

Please Take Out a Piece of Paper Write Down:

3 things you learned 2 things you found interesting 1 thing you still don’t understand or one question

you still have

Plato & Aristotle believed species were fixed & could be arranged according to their complexity

In the mid eighteenth century, Carolus Linnaeus developed a system of classification that called binomial nomenclature

George Cuvier, in the eighteenth century, explained changes in the fossil record by proposing that a whole series of catastrophes (extinctions) and re-populations from other regions had occurred giving the appearance of change over time

Prior to Darwin, it was thought that the world was young & species did not change