Class Notes (834,865)
Canada (508,771)
Biology (2,930)
BIO2129 (133)
Lecture

lec 14.docx

3 Pages
95 Views
Unlock Document

Department
Biology
Course
BIO2129
Professor
Jon Houseman
Semester
Fall

Description
The Permian (297-251 mya) o During the Permian period, the continents united to form the supercontinent Pangaea o Massive volcanic eruptions: ash blocked sunlight and cooled the climate => largest glaciers in Earth’s history. o By the end, reptiles greatly outnumbered amphibians. o The lineage leading to mammals diverged from one line of reptiles. Bony fishes radiated in the oceans. o Mass extinction at end: 96% species lost (volcanoes, meteorite & ocean turnover implicated) o At the end of the Permian, a large meteorite crashed into northwestern Australia. o Volcanic eruptions poured lava into the oceans, which depl2ted O in deep oceans. Oceanic turnover then carried the depleted water to the surface where it released2toxic2CO and H S. o O2concentrations dropped to about 12 percent—most animals would have been unable to survive at elevations above 500 m. o About 96% of all species on Earth became extinct. Mesozoic Era (251–65 mya) o At the start of the Mesozoic era (248 mya), the few surviving organisms found themselves in a relatively empty world. o Pangaea slowly separated, glaciers melted, and shallow inland seas formed. o Life proliferated and diversified. o Earth’s biota diversified and became distinct on each continent (previously more homogeneous).  Earth’s biota became increasingly provincialized: that is distinct terrestrial biotas evolved on each continent o By end of the era, the continents were close to their present positions and many organisms looked similar to those living today o Divided into The Triassic, The Jurassic, and The Cretaceous The Triassic (251-200 mya) o Pangaea began to break apart o Vertebrate & invert. lineages became more diverse. o Conifers and seed ferns became the dominant trees. o Frogs and turtles appeared. o Rise of reptiles, which gave rise to dinosaurs, crocodilians, and birds. o Mass extinction at end: 65% of the species lost. o A mass extinction at the end linked to a meteorite impact in present-day Quebec. The Jurassic (200-145 mya) o Two large continents: Laurasia (Laurentia (= NA) + Eurasia) & Gondwana (after region in India, contained India + all southern continents). o Ray-finned fishes began the great radiation that culminated in their dominance of the oceans. o Salamanders and lizards first appeared. o Flying reptiles! (pterosaurs) o Dinos: bipedal predators and quadrupedal herbivores. o Mammals first appeared. o Plant evolution continued with the emergence of the flowering plants that dominate Earth’s vegetation today The Cretaceous (145-65 mya) o Gondwana breaking apart, and a continuous ocean circled the tropics. Sea levels were high & Earth was warm and humid. o Flowering plants (angiosperms) evolved from gymnosperms. Many groups of mammals had evolved, but most were small. First snakes! o Mass extinction at end of Cretaceous; it was probably caused by a large meteorite colliding with Earth. o All vertebrates larger than about 25 kg in body weight, including all of the dinosaurs, apparently became extinct as a result of this impact. Cenozoic (65 mya) o By the early Cenozoic era (65 mya), the continents were close to their present-day positions; however, Australia was still a
More Less

Related notes for BIO2129

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit