The modern biota evolved during the Cenozoic era.docx

1 Page
Unlock Document

University of Calgary
Biomedical Engineering
BMEN 515
William Huddleston

The modern biota evolved during the Cenozoic era  By early Cenozoic ear (65 mya), the positions of the continents resembled those of today.  Cenozoic was characterized by extensive radiation of mammals.  Flowering plants diversified extensively and came to dominate world forests, except in cool regions.  Mutations of two genes in one group of plants allowed them to use atmospheric nitrogen directly by forming symbioses w/ a few species of nitrogen-fixing bacteria; dramatically increased the amount of nitrogen available for terrestrial plant growth.  THE TERTIARY (65-1.8 MYA) o Australia began its northward drift. o Early in this era, it was hot and humid; the ranges of many plants shifted latitudinally. o In the middle of this era, Earth’s climate became considerably drier and cooler. o Many lineages of flowering plants evolved herbaceous forms; grasslands spread over much of Earth. o Snakes and lizards underwent extensive radiations (birds and mammals too). o Three waves of mammals dispersed from Asia to North America across the land bridge. o Rodents, marsupials, primates, and hoofed mammals appeared in N. America for the first time.  THE QUATERNARY (1.8 MYA to PRESENT) o Is subdivided into two epochs, the Pleistocene and the Holocene. o The Pleistocene was a time of drastic cooling and climate fluctuations; 4 major and 20 minor “ice ages” cause the spreading of massive glaciers across the continentsranges of the animals and plants shifted toward the equator. o Relatively few species became extinct during these climate fluctuations. o Pleistocene was
More Less

Related notes for BMEN 515

Log In


Don't have an account?

Join OneClass

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

Sign up

Join to view


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.