5-1-6 Embryology Flashcards
The “body plan” of an animal is revealed as the embryo develops.
What are the common features of the “body plan” of all vertebrates during embryo development?
- A notochord
- A pair of pharyngeal pouches.
The notochord develops into the spine.
The pharyngeal pouches develop into gills in fish and amphibians. They develop into middle ear cavity, auditory tube, tonsils, and glands in humans.
The similarity suggests that fish are the ancestors of other vertebrates.
What are vestigial structures?
Remains of a body structure that served a purpose in some ancestor but that no longer function in the recent organism.
Examples of vestigial structures
reduced wings in ostriches, which do not fly
tailbone in humans, who do not have tails
Biochemistry similarities
All living organisms use the same basic biochemical molecules, including DNA and ATP. They have the same genetic code (with the exception of mitochondria), similar enzymes, and similar sequence patterns in the introns of their DNA.
The similarity suggest common ancestry for all living organisms.
What observation suggest that all living organisms share a common ancestor?
They use the same basic biochemical molecules including DNA and ATP. They have the same genetic code (with the exception of mitochondria), similar enzymes, and similar sequence patterns in the introns of their DNA.
What observation suggest that fish is the ancestor of other vertebrates?
All vertebrates have common features during embryonic development. The notocord develops into spine and the pharyngeal pouches develop into gills in fish and middle ear cavity, auditory tube, tonsils, and glands in humans.
In what way can vestigial structures used to identify an evolutionary ancestor?
Body structures that no longer function may indicate an ancestor that used those structures. For example, wing-like structures in an animal that does not fly may suggest a bird ancestor.
