ERTH 2401 - Midterm 1 With
Complete Solution
Dinosauria - ANSWER Triceratops horridus, Passer domesticus (sparrow;
a representative derived bird), and all members of the
clade descended from their most recent common ancestor.
Dinosaurs - ANSWER - are tetrapods
- are terrestrial
- have scales or feathers
- Femur head turned into socket
- Legs fully under body giving it a narrow gait
-have a bipedal, narrow stance with the femur head inserted into the
acetabulum of the sacrum.
- walk on their toes
Late Proterozoic - ANSWER - 1000 Ma: 1st eukaryotes
- 750 Ma: first animal traces (protozoa)
- 600 Ma: Oxygen accumulates forming Ozone layer
- 550 Ma: 1st fossil evidence for jellies, sponges, corals
Early Cambrian (541 - 509 Ma) - ANSWER - modern phyla of animals begin to
appear in the fossilrecord.
,- diversification of living things in the oceans: chordates, arthropods (e.g.
trilobites, crustaceans),echinoderms, molluscs,
Phylum Chordata - ANSWER Possesses a notochord, a dorsal nerve cord,
pharyngeal slits, and a post-anal tail. Bilateral symmetry.
ex: Pikaia graciens.
Middle Cambrian (509 - 497 Ma) - ANSWER ~508 Ma - Burgess Shale fauna
preserved. One of the earliest fossil beds containing soft-bodied animal
imprints
Late Ordovician - ANSWER - life continued to diversify and
Cambrian forms went extinct. First chondrichthyan-like scales.
Silurian (444 - 419 Ma) - ANSWER -430 Ma - First cartilaginous fishes in the
fossil record. Sharks diversify rapidly after this.
-420 Ma - First appearance of jawed & bony fish. More complex vascular
plants, spider-like arachnids and land scorpions appear on the land.
Early Devonian (419 - 393 Ma) - ANSWER - Oceans dominated by Placodermi;
sharks diversify; agnathans decline; first ammonites.
- Plants evolve leaves and roots; lycopod forests cover the land; terrestrial
arthropods diverse and common.
- Sea Level is high and vast coral reef systems develop
Late Devonian (383 - 359 Ma) - ANSWER - Tetrapods can support their
bodies and invade the land.
- Late Devonian extinction starts ~ 375 Ma killing all placoderms and 99% of
, trilobites.
Carboniferous (359-323 Ma) - ANSWER - Continents collided to form
Pangaea.
- Labyrinthodontia and Lepospondyli amphibians dominant land vertebrates,
some >2m.
- Arthropods very common.
- Vast forests
Late Carboniferous (Pennsylvanian)(323 - 299 Ma) - ANSWER - some
invertebrates achieve giant size
- Amniote egg evolves allowing reptiles to rapidly evolve and
exploit the dry land.
- 320 Ma - Synapsids separate from sauropsids (reptiles).
Permian (299 - 251 Ma) - ANSWER -Carboniferous rainforest collapse
creates vast deserts.
- Lycopods replaced by the more advanced seed ferns.
- Early conifers, ginkos & cycads radiate.
-Ancestral amniote groups of the mammals, turtles, & archosaurs arise.
Permian-Triassic Extinction - ANSWER -Largest mass extinction in Earth's
history.
-Up to 95% of marine species & 70% land organisms go extinct.
-Ecosystems took 30 million years to recover in the Triassic.
Complete Solution
Dinosauria - ANSWER Triceratops horridus, Passer domesticus (sparrow;
a representative derived bird), and all members of the
clade descended from their most recent common ancestor.
Dinosaurs - ANSWER - are tetrapods
- are terrestrial
- have scales or feathers
- Femur head turned into socket
- Legs fully under body giving it a narrow gait
-have a bipedal, narrow stance with the femur head inserted into the
acetabulum of the sacrum.
- walk on their toes
Late Proterozoic - ANSWER - 1000 Ma: 1st eukaryotes
- 750 Ma: first animal traces (protozoa)
- 600 Ma: Oxygen accumulates forming Ozone layer
- 550 Ma: 1st fossil evidence for jellies, sponges, corals
Early Cambrian (541 - 509 Ma) - ANSWER - modern phyla of animals begin to
appear in the fossilrecord.
,- diversification of living things in the oceans: chordates, arthropods (e.g.
trilobites, crustaceans),echinoderms, molluscs,
Phylum Chordata - ANSWER Possesses a notochord, a dorsal nerve cord,
pharyngeal slits, and a post-anal tail. Bilateral symmetry.
ex: Pikaia graciens.
Middle Cambrian (509 - 497 Ma) - ANSWER ~508 Ma - Burgess Shale fauna
preserved. One of the earliest fossil beds containing soft-bodied animal
imprints
Late Ordovician - ANSWER - life continued to diversify and
Cambrian forms went extinct. First chondrichthyan-like scales.
Silurian (444 - 419 Ma) - ANSWER -430 Ma - First cartilaginous fishes in the
fossil record. Sharks diversify rapidly after this.
-420 Ma - First appearance of jawed & bony fish. More complex vascular
plants, spider-like arachnids and land scorpions appear on the land.
Early Devonian (419 - 393 Ma) - ANSWER - Oceans dominated by Placodermi;
sharks diversify; agnathans decline; first ammonites.
- Plants evolve leaves and roots; lycopod forests cover the land; terrestrial
arthropods diverse and common.
- Sea Level is high and vast coral reef systems develop
Late Devonian (383 - 359 Ma) - ANSWER - Tetrapods can support their
bodies and invade the land.
- Late Devonian extinction starts ~ 375 Ma killing all placoderms and 99% of
, trilobites.
Carboniferous (359-323 Ma) - ANSWER - Continents collided to form
Pangaea.
- Labyrinthodontia and Lepospondyli amphibians dominant land vertebrates,
some >2m.
- Arthropods very common.
- Vast forests
Late Carboniferous (Pennsylvanian)(323 - 299 Ma) - ANSWER - some
invertebrates achieve giant size
- Amniote egg evolves allowing reptiles to rapidly evolve and
exploit the dry land.
- 320 Ma - Synapsids separate from sauropsids (reptiles).
Permian (299 - 251 Ma) - ANSWER -Carboniferous rainforest collapse
creates vast deserts.
- Lycopods replaced by the more advanced seed ferns.
- Early conifers, ginkos & cycads radiate.
-Ancestral amniote groups of the mammals, turtles, & archosaurs arise.
Permian-Triassic Extinction - ANSWER -Largest mass extinction in Earth's
history.
-Up to 95% of marine species & 70% land organisms go extinct.
-Ecosystems took 30 million years to recover in the Triassic.
