Your inner Fish

Pax 2 gene

Starts a chain reaction of gene activity that leads to the formation and development of the inner ear

Experiments on chick embryos in the 1960s & 50s and their significance

The discovery of the organizer gene sonic hedgehog in the ZPA or the zone of polarizing activity. Sonic hedgehog is responsible for the formation of our digits: our fingers and toes

What part of the human ear is unique to mammals

The malleus and incus from the inner ear

Conodonts

They were first thought to be small Shelly organisms with a series of spikes projecting out of them; they are really just the teeth of an ancient jawless fish.

Shubin's statement about scales, feathers, and breasts

We would never have scales, feathers or breasts if we did not have teeth in the first place because the developmental tool that make teeth have been repurposed to make the other important skin structures.

What are choanoflagellates?

a group of free-living unicellular and colonial flagellate eukaryotes considered to be the closest living relatives of the animals.

Endoderm

innermost germ layer; develops into the linings of the digestive tract and much of the respiratory system

Mesoderm

middle germ layer; develops into muscles, and much of the circulatory, reproductive, and excretory systems

Amphioxus

small marine animals - invertebrates- doesn't lose notochord

Collagen

structural protein found in the skin and connective tissue; most common protein found in the human body

ontogeny recapitulates phylogeny

the development of an organism (ontogeny) expresses all the intermediate forms of its ancestors throughout evolution (phylogeny)

Ectoderm

the outer layer of the embryo; will become hair, outer layer of skin, and the nervous system outermost germ layer; produces sense organs, nerves, and outer layer of skin

trigeminal nerve

Cranial nerve responsible for chewing and face sensations

The blastocyst stage

First time two distinctive tissues are present; a hollow sphere of trophoblast cells, inside of which is a small cluster of cells called inner cell mass

What environmental conditions favors evolution

High levels of oxygen in the atmosphere

Pax 6 and eyeless gene

Involved in the development of all known animal eyes and light sensing organs; Gene that causes lack of eye

Could tiktaalik survive in an arctic climate?

No, because