What is the Evidence for Evolution?
Biologists teach us that all living things on Earth are related but is there any solid evidence to back this claim? Let’s watch the Stated
Clearly video What is the Evidence for Evolution? (https://www.youtube.com/watch?v=lIEoO5KdPvg) and you can decide for yourself.
Watch the video and fill in the blanks as you go:
The theory of biological evolution make 2 claims about living creatures:
1. All living things are ________________ – they evolved from a ________________ ancestor.
2. Evolution is powered by _______________ processes.
Observable facts about evolution have been grouped into Independent Lines of _________________.
There are _____ million species alive today so we will focus one branch of the evolutionary tree: cetaceans. This branch includes
____________, dolphins and porpoises. Biologists tell us they evolved from an ancient 4 legged __________ _______________. Let’s
look at the facts:
1. Comparative Anatomy (the study of differences and similarities
2. Embryology (study of how creatures develop before
between living things)
birth/hatching)
Whales live in the water and look like ‘giant _______’ but like
land mammals they have the following features:
When a dolphin and human embryo are compared,
two things are interesting:
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placentas and give ________ birth
feed milk to their young
are __________-blooded
two fully developed __________ (no gills)
blowholes (like nasal passages in mammals)
_________
arm, wrist, _____________ and finger bones
unused ‘leg’ bones
1. Both embryos have arm and leg buds but only
the _______________ actually grows legs.
2. In dolphins, the early fetus has ____________
grooves on the front of the face. As the dolphin
grows, the nostrils migrate to the top of the
head and fuse together, becoming the dolphin’s
_________________.
3. Fossil Record
Basilosaurid whales (about 34-_____ million years ago)
Key points:
 They are an intermediate species between land and sea mammals
 They have small fully developed ______, legs, ankle, feet and toe bones.
 Legs too small for walking but may have been used for ____________ or
scratching away parasites.
Maiacetus Inuus (about ______ million years ago)
Key points:
 its hip bones seemed sturdy enough to walk on land but it is considered to be a
whale because:
o their skeletons have all been found with other _______ _______________.
o its short legs with long flattened toes suggest they were strong swimmers
with __________________ hands and feet.
o their skull has features of Basilosaurids and modern whales
o it appears to be a “__________________ whale”
DNA Comparisons
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DNA molecules contain chemical __________ that act like recipes for living things
Can determine who is most closely related to whom
The closest DNA match to the whale is the ___________
Whales and hippos may have evolved from a common ancestor around _____ million
years ago
 A closer look shows whales and hippos share some strange features:
o weird ankles
o give birth and nurse young ___________ ___________
o multi-chambered _______________
o both missing a coat of fur
o internal ________________
The video presents four independent lines of evidence that tell the same story: that
whales evolved from ____________________________________________.