Download Name: Date: Subject: Evidence for Evolution Objectives Objective 1

Name:
Date:
Subject:
Evidence for Evolution
Objectives
Objective 1: ASWBAT describe what the fossil record is and how it provides evidence for
the theory of evolution.
Objective 2: ASWBAT describe what comparative embryology is and how it provides
evidence for the theory of evolution.
Objective 3: ASWBAT describe what vestigial structures are and how they provide
evidence for the theory of evolution.
Objective 4: ASWBAT describe what comparative anatomy is and how it provides evidence
for the theory of evolution.
Objective 5: ASWBAT describe what selective breeding is and how it provides evidence for
the theory of evolution.
On a scale of 1 – 3 how well can you meet this objective now.
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2 – I know it a little bit
3 – I know it very well)
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Key Vocabulary Words
On a scale of 1 – 3 rate how well you know the vocabulary words below.
(1 – Not at all 2 – I know it a little bit 3– I know it very well)
Comparative Anatomy
Embryology
Selective Breeding
Fossil Record
Vestigial Structures
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Evidence for Evolution
At the heart of the theory of evolution is the basic idea that life has existed for billions of
years and has changed over time. All theories however, need evidence to support them.
Evolution is supported by lots of evidence that has been gathered by scientists over the
past several hundred years.
The evidence does one of two things.
1. Show that living things have changed.
2. Suggests that they have a common ancestor.
Fossil Record
Gathering fossils dates to at least to the beginning of recorded history. The fossils
themselves are referred to as the fossil record. The fossil record consists of all of the
information scientist have learned from fossils. It was one of the early sources of data
underlying the study of evolution and continues to be relevant to the history of life on
Earth. Scientists examine the fossil record to understand the process of evolution and the
way particular species have evolved. By using radioactive dating techniques, scientists are
able to estimate how old a fossil is and piece them to together to get an incomplete view of
how life has changed over the history of earth. Fossils also show us that many organisms
that have existed in the past looked very different to what we see on Earth today.
Examples of Fossils
Fossil Evidence for the Evolution of Horses
1. What is the fossil record?
Answer:
2. How does the fossil record provide evidence for the theory of evolution?
Answer:
Comparative Embryology
Comparative embryology is the study of the similarities and differences in the embryos
of different species. Similarities in embryos are evidence of common ancestry. All
vertebrate embryos, for example, have gill slits and tails, as shown in the diagram below.
All of the animals in the figure, except for fish, lose their gill slits by adulthood. Some of
them also lose their tail. In humans, the tail is reduced to the tailbone. Thus, similarities
that organisms share as embryos may be gone by adulthood. This is why it is valuable to
compare organisms in the embryonic stage.
Video Link: What can embryos tell us about evolution?
https://www.youtube.com/watch?v=uAZmLYWEPGk
The Development of 6 Different Embryos
1. What is comparative embryology?
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2. Describe two similarities you can see in the embryos above.
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3. How does comparative embryology provide evidence for the theory of evolution?
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Vestigial Structures
A vestigial structure is an anatomical feature that no longer seems to have a purpose in
the current form of an organism of the given species. Often, these vestigial structures were
organs that performed some important function in the organism at one point in the past.
However, as the population changed due to natural selection, those structures became less
and less necessary until they were rendered pretty much useless. While most of these
types of structures would probably disappear over many generations, some seem to keep
being passed down to offspring even though they have no known function. These
structures prove that the organism has changed and evolved over time by providing
evidence that they once used these now useless structures.
Examples of Vestigial Structures
Pelvic Bones in Whales
Human Tailbone
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Manatee Toenails
1. What is a vestigial structure?
Answer:
2. Describe one example of a vestigial structure.
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3. How do vestigial structures provide evidence for the theory of evolution?
Answer:
Comparative Anatomy
Comparative anatomy is the study of the similarities and differences in the structures of
different species. It studies how the structures (limbs, organs, etc.) in different organism
are different and alike. These structures may or may not have the same function in the
organisms being compared. In the 4 mammals below, they all have the same basic pattern
of bones in their forelimbs. This is evidence that they inherited this pattern from a
common ancestor.
Forelimbs of 4 Mammals
1. What is comparative anatomy?
Answer:
2. How does comparative anatomy provide evidence for the theory of evolution?
Answer:
Selective Breeding
Farmers and breeders have been using the idea of selection to cause major changes in the
features of their plants and animals for centuries. Farmers and breeders allowed only the
plants and animals with desirable traits to reproduce, causing the evolution of the animals
and plants that they breed. This process is called selective breeding or artificial selection
because people (instead of nature) select which organisms get to reproduce. Selective
breeding provides evidence for evolution by proving that organisms can change
drastically over time. By only allowing the organisms with the most useful traits to breed
and pass on those traits, farms and animal breeders have changed the original organisms
so much that most plants and animals that we use today look almost nothing like what
they did when they were first discovered in the wild.
Selective Breeding of Common Foods From Wild Mustard Plants
Selective Breeding of Dogs From Wolves
Video Link: Selective Breeding of Dogs http://www.hhmi.org/biointeractive/dogbreeding
Video Link: Super Cow – Selective Breeding https://www.youtube.com/watch?v=IDNQeVhQTc
1. What is selective breeding?
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2. How does selective breeding provide evidence for evolution?
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Video: Evidence for Evolution
Quiz
Directions: Answer the following questions to see if you met the objectives.
1. What is the fossil record?
Answer:
2. How does the fossil record provide evidence for the theory of evolution?
Answer:
3. What is comparative embryology?
Answer:
4. How does comparative embryology provide evidence for the theory of evolution?
Answer:
5. What is a vestigial structure?
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6. Describe one example of a vestigial structure.
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7. How do vestigial structures provide evidence for the theory of evolution?
Answer:
8. What is comparative anatomy?
Answer:
9. How does comparative anatomy provide evidence for the theory of evolution?
Answer:
10. What is selective breeding?
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11. How does selective breeding provide evidence for evolution?
Answer: