What is the Cambrian explosion quizlet?
What is the Cambrian explosion quizlet?
What was the Cambrian Explosion? It was the sudden appearance (over a 10my period) of many different organisms, which occurred approx 540-548 mya. So it can be away from sources of oxygen, preventing microorganisms from decomposing the organism.
What events occurred at the beginning of the Cambrian period approximately 542 million years ago?
The Cambrian explosion, or less commonly Cambrian radiation, was the relatively short evolutionary event, beginning around 542 million years ago in the Cambrian Period, during which most major animal phyla appeared, as indicated by the fossil record.
Which of the following pairs of modern chordate groups are most closely related?
lancelets and coelacanths are more closely related than are chimaeras and coelacanths.
What is the function of somites?
Somites give rise to the cells that form the vertebrae and ribs, the dermis of the dorsal skin, the skeletal muscles of the back, and the skeletal muscles of the body wall and limbs.
What is Sclerotome?
Medical Definition of sclerotome : the ventral and mesial portion of a somite that proliferates mesenchyme which migrates about the notochord to form the axial skeleton and ribs.
What is the difference between somites and Somitomeres?
In the developing vertebrate embryo, the somitomeres (or somatomeres) are cells that are derived from the loose masses of paraxial mesoderm that are found alongside the developing neural tube….Somitomere.
| Somitomeres | |
|---|---|
| Details | |
| Gives rise to | somites |
| Identifiers | |
| Latin | somitomera |
What is occipital Somite?
Somites are cellular masses originating from paraxial mesoderm on both sides of neural tube during embryogenesis. They incorporate into the occipital area of embryonic skull, give rise to the tongue muscles and also condense to contribute to the basi-occipital and exo-occipital cartilages.
What stage does Somitogenesis occur in the chick embryo?
The term somitogenesis is used to describe the process of segmentation of the paraxial mesoderm within the trilaminar embryo body to form pairs of somites, or balls of mesoderm. In humans, the first somite pair appears at day 20 and adds caudally at 1 somite pair/90 minutes until on average 44 pairs eventually form.
What is the first period of embryogenesis?
The process of prenatal development occurs in three main stages. The first two weeks after conception are known as the germinal stage, the third through the eighth week is known as the embryonic period, and the time from the ninth week until birth is known as the fetal period.