Download Evolution worksheet File

Evolution
Evolution is the gradual development of different species from a common ancestor. The theory of evolution states that life on Earth has changed
over time.
History: Jean Baptiste Lamarck (1744-1829) was the first to try and explain how species could change and evolve. His explanation for how
speciation occurs (how new species are formed) was incorrect.
He believed that:
 an organ improved or became weaker when it was used repeatedly or weakened through lack of use
 The change that was developed was a result of its environment (now, this is called an acquired characteristic)
× The change to the organ is passed on through reproduction to the next generation
Explain why Lamarck’s theory is wrong
Charles Darwin (1809-1882) came up with the currently believed theory to explain how species change and evolve.
He believed that:
 Current species have evolved from a common ancestor
 That the evolution of new species (speciation) occurs through a process called natural selection.
There are four stages of the natural selection cycle:
o Variation occurs in all offspring
o Many offspring are produced (more than can possibly survive)
o There is competition between offspring
o Only the fittest individuals survive
Since then, scientists have discovered DNA and genetics. Darwin’s theory can now be understood with genetics, called neo-Darwinism.
That is, evolution occurs through the process of natural selection where the variation that appears in all populations is because of genetic variation
between individuals.
Evidence for evolution
1. Anatomical studies
2. Distribution of plants and animals
3. Biochemistry
4. Fossils
5. Genetic evidence (hint: diversity of life, classification of living creatures)
1. Anatomical studies : Homologous structures
Go to Moodle and download the textbook excerpt called “Evolution”. Read page 149,
“Evidence for evolution” about fossils.
Look at Figure 3.7.4 and how the common ancestor of the horse, the Hyracotherium
(Eohippus), had feet with toes.
Now, look at Fig.3.3.11 (to the right)
Describe the similarities between each organisms arm.
Describe the differences between each organisms arm.
Explain why this is considered evidence for evolution.
2. Distribution of plants and animals : Follow the link about a tree species called Glossopteris and watch the video/read the webpage
http://nhm.ac.uk/nature-online/earth/fossils/glossopteris/index.html
Glossopteris is a fossil found around the world in the Southern Hemisphere. Many of the plants found in the Southern Hemisphere have the
common ancestor of the Glossopteris tree (they have similar characteristics to it) . Explain how this fossil can help explain evolution (hint:
continental drift and climate change)
3. Biochemistry: “The Beginning of life”
What molecules are all living things built of? (hint: organic molecules)
4. Fossils: Research about the bird-like dinosaur, called an Archaeopteryx
http://evolution.berkeley.edu/evolibrary/article/lines_03
and
http://www.nyit.edu/medicine//research/cetacean_family_tree_aetiocetus_weltoni
What is a “transitional form”?
List the features that Aetiocetus has that are similar to whales today. Compare these to the fossil record for land mammals?
Explain why a TRANSITIONAL FORM is considered evidence for evolution
5. Genetic evidence : the diversity of life and the classification of living creatures
Go back to the textbook you downloaded from Moodle, called “Evolution”. Read page 149, “Evidence for evolution” about DNA
Describe how DNA is used to identify whether two species have a recent common ancestor.
Go to the following link http://www.bbc.com/earth/bespoke/story/20150311-the-15-tweaks-that-made-us-human/index.html
What do you think are the 5 most interesting “weird” characteristics humans have evolved? (list them)
Why is DNA considered evidence for evolution?