Class Notes (836,294)
Canada (509,749)
Biology (6,817)
Biology 1001A (1,727)
Tom Haffie (1,170)
Lecture 18

Lecture 18.docx

3 Pages
Unlock Document

Biology 1001A
Tom Haffie

Chapter 20.2, 20.4, 20.6 (Lecture 18) 20.2- Changes in Earth • Plate tectonics can be responsible for phenomena such as continental drift and have strong influences on the distribution and evolution of organisms • Changes in Earth’s crust can also cause calamitous events, such as earthquakes, which also have implications for living organisms Patterns in macroevolution • The fossil record • Mode and tempo evolution • Evolutionary trends: changes in body size 20.4- The Fossil Record • Most fossils are found in sedimentary rocks • Conditions of low oxygen or high acidity are ideal for fossilization. • Hard structures such as skeletons and teeth do not readily decompose and are more often fossilized than softer structures. o Some fossils are casts or moulds; in others, the original materials are replaced by dissolved minerals • The availability of fossils is highly skewed toward certain areas, certain organisms, or parts of organisms • Scientists can assign relative and absolute dates to geological strata and the fossils they contain o Sequence of fossils in the lowest (oldest) to the highest (newest) strata reveals their relative ages o Radiometric dating is based on the decay rates of unstable isotopes and permits absolute dating (half-lives) • Fossil Record is incomplete and biased o Most species have never formed fossils o Biases in fossil record  Temporal- more likely to find new fossils than old fossils due to erosion, etc.  Taxonomic- not everything is likely to fossilize  Habitat- Some environments are better for fossil formation i.e. ocean good environment 20.6- Interpreting Evolutionary Lineages • The evolution and adaptive radiation of horses demonstrate that many species arise
More Less

Related notes for Biology 1001A

Log In


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.