Download The Saylor Foundation 1 Answer Key to Unit 3 Quiz 1. The five

Answer Key to Unit 3 Quiz
1. The five stages in the evolution of vertebrate endoskeleton are the hydroskeleton, the
hydrostatic skeleton, the sclerotome skeleton, the neural skeleton (notochord), and the
neuro-muscular skeleton (vertebrate skeleton).
2. The following are two main changes that mark the transition from non-chordate to
chordate characters in animal evolution.
A. The nervous system, which is situated on the ventral aspect of the body, now comes
to be developed on the surface of the dorsal aspect of the body, and a rigid notochord is
formed from the enteron, which serves to support it.
B. The hydrostatic skeleton, which occupies the closed coelomic spaces, disappears
and is replaced by the sclerotome skeleton.
3. Fill in the blanks. Nervous tissue is composed of two main cell types: neurons and
glial cells. Neurons transmit nerve messages.
4. The three types of neurons found are sensory, motor, and interneurons.
5. The main difference in the nervous system of a chordate and non-chordate is that
most non-chordates lack proper nervous system but possess a nerve net. Also,
chordates possess specialized nervous system consisting of a brain and spinal cord.
6. Otoliths sense linear accelerations. Humans possess utricule and saccule in the
inner ear which function as otoliths.
7. Ocelli or simple eyes are found in invertebrates. They are basically devoid of lens or
conea as is present in a complex vertebrate eye.
8. The main differences between open and closed circulatory systems follow.
Open circulatory systems (evolved in crustaceans, insects, mollusks, and other
invertebrates) pump blood into a hemocoel with the blood diffusing back to the
circulatory system between cells.
Closed circulatory systems have the blood closed at all times within vessels of different
size and wall thickness. In this type of system, blood is pumped by a heart through
vessels found in vertebrates mainly.
9. The main types of immunity are innate immunity, which we are born with, and
adaptive immunity, which the body acquires as a result of exposure to a certain
pathogen.
The Saylor Foundation 1
10. The following match the type of reproduction to its counterpart.
A. Amoeba: Binary fission
B. Hydra: Budding
C. Lizards: Parthenogenesis
D. Mammals: Sexual
11. Spermatogenesis is the development of spermatocytes in males. Oogenesis is the
development of egg/oocyte in females.
The Saylor Foundation 2