Charles Darwin and his Theory of
Evolution
Part One: Charles Darwin, Adaptation

 Be able to define evolution.
 Be able to identify a physical difference between two given animals, and formulate a reason why these adaptations are useful for their individual environments.
 Be able to list and give a short definition of 4 of the 5 evidences of evolution.

 https://www.youtube.com/watch?v=lX7veVXwRi8

 Neither the planet nor the species that inhabited it had changed since the beginning of time.

Charles Darwin: (1809-1882)
Father of Evolution
Scientist credited with the Theory of Evolution & Natural Selection

 When he was 22, Darwin was invited to join the HMS
Beagle.
 He spent 5 years travelling round the world as a naturalist.
 A naturalist makes observations about the natural world.
 Darwin kept a scientific journal of his findings.

 The finches on each island in the Galapagos had different types of beaks.
 They differed in shape, length, strength, etc.
 Question: Why would different finches have different types of beaks?

 Darwin also observed that tortoises on each island in the
Galapagos had different sizes of shells, and some tortoises had longer necks than others.
 Question: Any ideas about the reason tortoises from different areas would have different shell and neck characteristics?

 Question: What does the world “adapt” mean?

 Question: What does the world “adapt” mean?
 Answer: make something suitable for a new purpose; modify, become adjusted to new conditions
 Biological definition: an alteration or adjustment in structure or habits, often hereditary, by which a species or individual improves its condition in relationship to its environment

 Darwin hypothesized that organisms had a common ancestor, but had adapted to their particular environments and changed over time.
 Evolution: change in the inherited characteristics of populations over generations.
 Darwin published his research in 1859 in his book “Origin of Species”

Evidence for Evolution:
Common Ancestry
 Common Ancestry: If species evolved from a common ancestor, then they should share common anatomical traits
 Hawaiian Honeycreeper: family of birds in Hawaii that have similar skeletons and muscles, indicating they are closely related.
 Over time, their common ancestor evolved into several species, each with a specialized bill for eating certain foods. Just like Darwin’s finches on the
Galapagos!

Evidence for Evolution:
Homologous Structures
 If animals evolved from a common ancestor, then they should share common structures – and they do!
 These are called homologous structures
 Homologous structures are parts of the body that are similar in structure to other species' comparative parts.

Evidence for Evolution:
Embryo Development
 What do you notice? List 2 observations.
 An embryo is an unborn (or unhatched) animal or human young in its earliest phases.
 This shows that the animals are similar and that they develop similarly, implying that they are related, have common ancestors and that they started out the same, gradually evolving different traits, but that the basic plan for a creature's beginning remains the same.

Evidence for Evolution:
Vestigial Organs
 Some organisms have structures or organs that no longer have a useful function.
 These structures or organs may have been useful to the ancestors of a species, but over time have evolved into what we term vestigial organs.
 Kiwi (flightless bird), Whales
(hind leg bones), Humans
(tailbone, appendix)

Evidence for Evolution:
Fossils
 Fossils provide a look into the past.
 Scientists can trace how a species has evolved by studying fossils.