DARWIN PRESENTS HIS IDEA

By: Sandy Gomez

Darwin presents his idea

Gathered data aboard the Beagle

Made important observations and conclusions

Linked his idea with other scientists findings

Trying to explain what other scientist

couldn’t: EVOLUTION

Darwin’s Reasoning

Plants or animals that arrived to Galapagos Island faced conditions that were different form those on mainland.

He hypothesized that organisms gradually changed over many generations and became better adapted to the new conditions.

Darwin presents his idea

Natural Selection:

Process by which, individuals who are

better adapted to the environment are

more likely to survive and reproduce than

other members of the same species.

Led to evolution, but how?

Natural Selection

1. There is variation in traits. For example, some beetles are green and some are brown

Natural Selection2. There is differential reproduction.Since the environment can't support unlimited population growth, not all individuals get to reproduce to their full potential. In this example, green beetles tend to get eaten by birds and survive to reproduce less often than brown beetles do

Natural Selection

3. There is heredity.The surviving brown beetles have brown baby beetles because this trait has a genetic basis.

Natural Selection4. End result:The more advantageous trait, brown coloration, which allows the beetle to have more offspring, becomes more common in the population. If this process continues, eventually, all individuals in the population will be brown.

Factors That Affect Natural Selection

Overproduction of the offspring Variation within species

Factors That Affect Natural Selection

Variations are inherited

Factors That Affect Natural Selection

Isolation

EVIDENCE OF EVOLUTION

Evidence of Evolution Fossils

Evidence of Evolution

Fossils

Saber Tooth Tiger

Evidence of Evolution Embriology

Evidence of Evolution Homologous Structures

Evidence of Evolution Analogous Structures

Evidence of Evolution Vestigial Structures

Evidence of Evolution Vestigial Structures

Evidence of Evolution Vestigial Structures

Important questions to answer

What is natural selection? Which are the conditions needed for

natural selection to occur? Describe each one and give an example.

Which are the main pieces of evidence that might prove evolution? Describe each one.

Why is each piece of evidence said to be it?