Download Embryology slideshow

Photos ©Life Magazine1994
and Adam Software 1995
Rendered images © Feeling
Tone Studios 1998
Embryos tend to look very
much alike early in
development. Later, as
more genes unique to the
species start to become
expressed, they start to
look different. The
embryos of related species
look alike for longer
periods of time. This is
because they have similar
genes that are expressed at
similar times.
On the following slide you
will see a pig and a human
embryo at approximately
the same point in
development. Note the
similarities
Now look at a chicken
embryo at about the same
stage.
Notice that it
does, in some
ways, resemble
the Human and
pig embryo but
is easily
distinguishable
Now compare some older
fetuses. Which is Human?
B
A
C
C is correct.
What do you think picture A is?
• lemur
• pig
• dog
• Star Wars character
What do you think picture B is?
• lemur
• pig
• dog
• Star Wars character
A
B
C is correct.
What do you think picture A is?
• lemur
• pig
• dog
• Star Wars character
What do you think picture B is?
• lemur
• pig
• dog
• Star Wars character
A
B
Now compare feet/hands
early in development.
And Later
Another comparison
One month Human embryo
Two month fetus
Three month fetus
Four month fetus
Six month fetus
A long time ago some scientists thought they saw a small
person in a sperm cell.
It would have been easier that way.