Review of Past Chapters
Approximately how old were the rocks in which the Tiktaalik was found?
Approximately 375 million years old.
Who is Neil Shubin?
The author of "Your Inner Fish"
Name the three middle ear bones.
Malleus, Incus, Stapes
After their discovery in the 1840s, the fossils were shipped to which scientist for identification and analysis?
Richard Owen
What makes box jellyfish different from other jellyfish?
Box jellyfish have eyes.
What does Pax 6 control the development of?
Pax 6 controls development in everything that has eyes.
60 years old.
Name the flap of the external ear that is only found in mammals.
Did Reichert reach his conclusion before or after Darwin established his notion of a family tree for life?
Before, by several decades.
What do fish use their neuromast organs for?
When neuromasts bend, the fish is given information about how the flow of water is changing.
What are the earliest known creatures that have fins with a skeleton inside?
Columbia, Harvard, and UC Berkley.
How does the book describe what the external ear looks like for amphibians and reptiles?
the top of a drum
Building off of Reichert, what did Ernst Gaupp discover?
Gaupp observed that the single bone in the reptilian middle ear is the same as the stapes of mammals; both are second-arch derivatives.
What is the large jaw bone in sharks that corresponds to the stapes in mmammals?
Hyomandibula
What genetic similarities do teeth, mammary glands, and feathers all share?
The biological processes that make these different organs are versions of the same thing.
What does Neil Shubin's work rely most heavily upon?
Fossils
Describe how the role of the "swishing gel" contributes to the perception of sound within the cochlea.
The swishing gel bends nerves, which sends a signal to the brain, which then interprets it as sound.
What link did W.K. Gregory see between Gaupp's embryos and the African fossils?
He observed that the most reptilian of the mammal-like reptiles had only a single bone in its middle ear; like other reptiles, it had a jaw composed of many bones.
What is nystagmus?
Nystagmus occurs when an individual is intoxicated and the alcohol causes their eyes to twitch when attempting to track an object. This is due to alcohol being in the cochlea, which convinces the brain that the individual is spinning.
What anatomical feature do we share with Amphioxus worms?
We share gill arches.
Which discovery is Neil Shubin most known for?
Tiktaalik roseae
Describe all of the components of the internal ear for mammals with as much detail as possible.
Cochlea, Semicircular canals, vestibular nerve, auditory nerve, Eustachian tube.
What were Karl Reichert's initial observations and what was his conclusion?
His initial observations were that two of the ear bones in the mammals corresponded to pieces of the jaw in the reptiles. The conclusion was that the same gill arch that formed part of the jaw of a reptile formed ear bones in mammals.
Regarding the fossils discovered in the 1840s, which features were similar to mammals?
Their teeth were similar to mammals.