BIO 370 Exam 2 Questions Answered Correctly Latest Update 2025-2026
Describe the traits and life histories of the extant Lepidosaurian clades - Answers Sphenodonts
(aka Tautara/Rhyncocephalia)
Only found on islands off of New Zealand
Have not changed in 220 million years
Diapsid skull (different from ancestral version, but plesiomorphy)
Two rows of teeth on upper jaw, one row of teeth on lower jaw : jaws close and then slide
forward to generate shearing
Parietal eye on top of head for sensing changes in light
Mostly nocturnal
Live in burrows (often near seabird colonies)
Carnivores that eat mostly invertebrates
Can take up to 1 year to hatch, 20 years to mature, can live to 100
Reproduce every few years, temp dependent sex determination
Describe how the continents have moved across the surface of the earth over geologic time -
Answers The plates move from magma activity. In early paleozoic, Cambrian there were two
main plates: Gondwana (modern Africa, Australia, Antarctica, South Asia) and Laurentia with
Baltica and Siberia. Toward the end of the Silurian they came together in the southern pole.
Then they drifted and came together around 335 mya to form Pangea with large areas near the
equator. This existed for around 160 years and began breaking up during the Jurassic. Today's
plates include the Eurasian, Indo-Australian, North and South American, African, Pacific, Cocos,
Nazca (all ocean plates).
Explain the role of changing climates and environments on vertebrate evolution - Answers The
earth has mostly been hotter than it is today. During Silurian, there were mosses, fungi and
small arthropods and worms on land. Land vertebrates evolved during the late Devonian when
sea levels fell, there was ocean anoxia and an extinction event. By late Devonian there were fern
forests on land and arthropods though no flying insects; these were carnivores or detrivores.
This was when the tetrapod outgroups such as osteolepiformes and ichthyostegids arose. In
the carboniferous oxygen levels rose and we get both further diversification of plants, with
weathering-resistant plant tissue and evolution of winged insects and huge insects. The
lissamphibian outgroups, the temnospondyls and lepospondyls, arose at this time. Amniote
initial radiation happened in the Permian.
Causes of temperature change: - Answers 10 million year cycle of solar radiation change;
,Milankovich cycles:
100,000 year cycle of eccentricity of orbit,
40,000 year cycle of tilt (obliquity of ecliptic),
20-odd thousand year cycle of precession
short-term CO2 variation affects temperature (methane and water vapor are also greenhouse
gases, but varies less).
Other changes - Answers Oxygen concentration changes in both air and ocean. Anoxia an issue
in Devonian, P-T, and Triassic-Jurassic extinctions. During periods of higher oxygen
concentration, animals invaded land twice (arthropods and then vertebrates) and insects and
later mammals grew larger.
List the causes of the three big Paleozoic mass extinctions - Answers Late Ordovican-Silurian
extinction
Late Devonian extinction
Permian-Triassic extinction
Late Ordovican-Silurian extinction - Answers Continents moved to south pole
Drop in CO2 levels
Glaciation/global cooling -> drop in sea level
Late Devonian extinction - Answers ocean volcanism
Ocean anoxia
Drop in sea level
Large vascular plants (dumping nutrients into sea, causing anoxia)
Permian-Triassic extinction - Answers Mass volcanism -> short term, rapid cooling
Release of methane -> long term, rapid warming
Formation of Pangaea -> loss of continental shelf habitat
Ocean anoxia
Hydrogen sulfide release -> toxic, uses up oxygen
Sea level fluctuations
, Possible meteor impact
Describe the challenges and opportunities of living in the terrestrial environment - Answers
Gravity
Viscosity
oxygen
water
temperture
energy
Gravity - Answers Body mass support sand resistance to blood flow
Support for respiratory structures lacking
Viscosity - Answers Reduced drag, but no fluid to support locomotion
Different light Filtering/volatility/electrotransmission properties
Oxygen - Answers Less intake of environmental medium necessary for respiration
Water - Answers water loss is a major issue and conservation is essential
Temperature - Answers great variation requires a solution
Energy - Answers locomotion more costly
lower prey density prey and prey capture modalities
Explain the morphological, physiological, and behavioral adaptations to living on land - Answers
Skeletal Adaptations
Feeding Adaptations
Reproductive Strategies
Respiration adaptations
Circulatory adaptations
Temperature regulation
Skin adaptations
Sight/Sound adaptations
Describe the traits and life histories of the extant Lepidosaurian clades - Answers Sphenodonts
(aka Tautara/Rhyncocephalia)
Only found on islands off of New Zealand
Have not changed in 220 million years
Diapsid skull (different from ancestral version, but plesiomorphy)
Two rows of teeth on upper jaw, one row of teeth on lower jaw : jaws close and then slide
forward to generate shearing
Parietal eye on top of head for sensing changes in light
Mostly nocturnal
Live in burrows (often near seabird colonies)
Carnivores that eat mostly invertebrates
Can take up to 1 year to hatch, 20 years to mature, can live to 100
Reproduce every few years, temp dependent sex determination
Describe how the continents have moved across the surface of the earth over geologic time -
Answers The plates move from magma activity. In early paleozoic, Cambrian there were two
main plates: Gondwana (modern Africa, Australia, Antarctica, South Asia) and Laurentia with
Baltica and Siberia. Toward the end of the Silurian they came together in the southern pole.
Then they drifted and came together around 335 mya to form Pangea with large areas near the
equator. This existed for around 160 years and began breaking up during the Jurassic. Today's
plates include the Eurasian, Indo-Australian, North and South American, African, Pacific, Cocos,
Nazca (all ocean plates).
Explain the role of changing climates and environments on vertebrate evolution - Answers The
earth has mostly been hotter than it is today. During Silurian, there were mosses, fungi and
small arthropods and worms on land. Land vertebrates evolved during the late Devonian when
sea levels fell, there was ocean anoxia and an extinction event. By late Devonian there were fern
forests on land and arthropods though no flying insects; these were carnivores or detrivores.
This was when the tetrapod outgroups such as osteolepiformes and ichthyostegids arose. In
the carboniferous oxygen levels rose and we get both further diversification of plants, with
weathering-resistant plant tissue and evolution of winged insects and huge insects. The
lissamphibian outgroups, the temnospondyls and lepospondyls, arose at this time. Amniote
initial radiation happened in the Permian.
Causes of temperature change: - Answers 10 million year cycle of solar radiation change;
,Milankovich cycles:
100,000 year cycle of eccentricity of orbit,
40,000 year cycle of tilt (obliquity of ecliptic),
20-odd thousand year cycle of precession
short-term CO2 variation affects temperature (methane and water vapor are also greenhouse
gases, but varies less).
Other changes - Answers Oxygen concentration changes in both air and ocean. Anoxia an issue
in Devonian, P-T, and Triassic-Jurassic extinctions. During periods of higher oxygen
concentration, animals invaded land twice (arthropods and then vertebrates) and insects and
later mammals grew larger.
List the causes of the three big Paleozoic mass extinctions - Answers Late Ordovican-Silurian
extinction
Late Devonian extinction
Permian-Triassic extinction
Late Ordovican-Silurian extinction - Answers Continents moved to south pole
Drop in CO2 levels
Glaciation/global cooling -> drop in sea level
Late Devonian extinction - Answers ocean volcanism
Ocean anoxia
Drop in sea level
Large vascular plants (dumping nutrients into sea, causing anoxia)
Permian-Triassic extinction - Answers Mass volcanism -> short term, rapid cooling
Release of methane -> long term, rapid warming
Formation of Pangaea -> loss of continental shelf habitat
Ocean anoxia
Hydrogen sulfide release -> toxic, uses up oxygen
Sea level fluctuations
, Possible meteor impact
Describe the challenges and opportunities of living in the terrestrial environment - Answers
Gravity
Viscosity
oxygen
water
temperture
energy
Gravity - Answers Body mass support sand resistance to blood flow
Support for respiratory structures lacking
Viscosity - Answers Reduced drag, but no fluid to support locomotion
Different light Filtering/volatility/electrotransmission properties
Oxygen - Answers Less intake of environmental medium necessary for respiration
Water - Answers water loss is a major issue and conservation is essential
Temperature - Answers great variation requires a solution
Energy - Answers locomotion more costly
lower prey density prey and prey capture modalities
Explain the morphological, physiological, and behavioral adaptations to living on land - Answers
Skeletal Adaptations
Feeding Adaptations
Reproductive Strategies
Respiration adaptations
Circulatory adaptations
Temperature regulation
Skin adaptations
Sight/Sound adaptations
