Bio 204 Lab 15 Questions
1. Name eight apomorphies for Mammalia.: -endothermy
-four-chambered heart with left aortic arch
-hair
-heterodont dentition
-mammary glands
-middle ear (3 bones)
-muscular, thoracic diaphragm
-single bone in lower jaw (dentary)
2. Distinguish between endothermy and ectothermy.: endothermy: *body heat is generated
internally* by the metabolism of food
ectothermy: body heat being obtained from the environment
3. What is the function of a heterodont dentition in mammals?: *Allows more precise
chewing* which is a step towards digestion in vertebrates with high metabolic rates
4. Why isn't egg laying an apomorphy for monotremes?: Not unique because it's a shared
feature that is inherited from a common amniote ancestor with other vertebrates such as turtles, lizards, snakes, and
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, birds
5. Name four tooth types found in mammals.: -bunodont type
-carnasial type
-lophodont type
-selenodont type
6. Name two apomorphies for Marsupialia.: - Choriovitelline placenta
- Marsupium
7. Name two apomorphies for Eutheria.: - Corpus callosum
- Chorioallantonic placenta
8. What morphological differences are there between the jaw point in mammals
and non-mammalian tetrapods?: new jaw articulation
9. What are the names of the three middle ear bones in mammals?: malleus, stapes,
incus
10. From which ancestral bones, involved in jaw articulation of all non-mam-
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1. Name eight apomorphies for Mammalia.: -endothermy
-four-chambered heart with left aortic arch
-hair
-heterodont dentition
-mammary glands
-middle ear (3 bones)
-muscular, thoracic diaphragm
-single bone in lower jaw (dentary)
2. Distinguish between endothermy and ectothermy.: endothermy: *body heat is generated
internally* by the metabolism of food
ectothermy: body heat being obtained from the environment
3. What is the function of a heterodont dentition in mammals?: *Allows more precise
chewing* which is a step towards digestion in vertebrates with high metabolic rates
4. Why isn't egg laying an apomorphy for monotremes?: Not unique because it's a shared
feature that is inherited from a common amniote ancestor with other vertebrates such as turtles, lizards, snakes, and
1/4
, birds
5. Name four tooth types found in mammals.: -bunodont type
-carnasial type
-lophodont type
-selenodont type
6. Name two apomorphies for Marsupialia.: - Choriovitelline placenta
- Marsupium
7. Name two apomorphies for Eutheria.: - Corpus callosum
- Chorioallantonic placenta
8. What morphological differences are there between the jaw point in mammals
and non-mammalian tetrapods?: new jaw articulation
9. What are the names of the three middle ear bones in mammals?: malleus, stapes,
incus
10. From which ancestral bones, involved in jaw articulation of all non-mam-
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