Charles Darwin observed various plants and animals during his voyage on the HMS Beagle. On the Galapagos Islands, he noticed that marine iguanas had adaptations for swimming while land iguanas had adaptations for climbing trees. He also saw that different species of finches had beaks adapted to their specific food sources. This led Darwin to conclude that natural selection results in organisms becoming perfectly adapted to their environments over generations, and to develop his theory of evolution.

1. Charles Darwin, Evolution,
&
Natural Selection: An Introduction
HMS Beagle

2. Charles Darwin
- Charles Darwin was a British naturalist (someone who studies nature)
who worked on a sailing ship named, the Beagle
- Darwin observed nature and took notes on everything he saw
HMS Beagle

3. Galapagos Islands
- One of the Beagle’s stops was the Galapagos Islands off the coast of South America
- Here Darwin observed many new plants and animals

4. Marine vs. Land Iguanas
- Two new animals Darwin saw were marine and land iguanas
- Darwin noticed the marine iguanas - Darwin also noticed the land
had long claws and flat noses to help iguanas had short claws which allow
them grip slippery rocks and eat them to climb trees and eat leaves
seaweed
Land Iguana
Marine Iguana

5. Yummy seaweed…

6. Darwin’s Finches
- Darwin also observed birds called finches
- Darwin noticed that some finches had beaks for grabbing insects,
some had beaks for crushing seeds, and others had beaks used for poking
around in tree bark.

7. Iguanas & Finches
- After observing the iguanas, finches, and many other organisms, Darwin
made a very important conclusion…
- Darwin concluded that each animal was perfectly adapted to their own
particular environment
Marine Iguana = adapted for eating seaweed underwater
Land Iguana = adapted for eating leaves in trees
Finches = beaks adapted to their food source

8. Adaptation, Natural Selection,
Adaptation
& Evolution
- When animals change in ways that help them to survive it is called an adaptation
(ex. long claws, short claws, & special beaks)
- Darwin then combined the idea of adaptation with a newer idea called
natural selection
Natural Selection
- When nature “selects” the animals that are BEST adapted to their environment
for survival
(ex. nature “selects” the marine iguanas for the ocean because of their
long claws – you don’t find short-clawed iguanas in the ocean)
- Darwin then created his famous theory of evolution where he explained
how evolution happens
Theory of Evolution
- Evolution, or change over time, occurs through the process of natural selection