Class Notes (885,372)
CA (530,043)
Western (51,412)
Biology (6,961)
1001A (1,758)
Tom Haffie (1,174)
Lecture 18

Biology Lecture 18.docx

2 Pages
102 Views

Department
Biology
Course Code
Biology 1001A
Professor
Tom Haffie

This preview shows 80% of the first page. Sign up to view the full 2 pages of the document.

Loved by over 2.2 million students

Over 90% improved by at least one letter grade.

Leah — University of Toronto

OneClass has been such a huge help in my studies at UofT especially since I am a transfer student. OneClass is the study buddy I never had before and definitely gives me the extra push to get from a B to an A!

Leah — University of Toronto
Saarim — University of Michigan

Balancing social life With academics can be difficult, that is why I'm so glad that OneClass is out there where I can find the top notes for all of my classes. Now I can be the all-star student I want to be.

Saarim — University of Michigan
Jenna — University of Wisconsin

As a college student living on a college budget, I love how easy it is to earn gift cards just by submitting my notes.

Jenna — University of Wisconsin
Anne — University of California

OneClass has allowed me to catch up with my most difficult course! #lifesaver

Anne — University of California
Description
Biology Lecture 18 Macroevolution When we say how closely related or how distantly related are two species what we really mean is how far back in evolutionary time did they last share a common ancestor Patterns in macroevolution o Most of what we know of macroevolution comes from the fossil record How old is that fossil o Law of Superposition when dealing with sedimentary rock formation rocks deposited in layers newer rocks get deposited on top of older layers o Therefore fossils embedded in the top layer of a particular rock formation are going to be more recent and fossils in the bottom layers are going to be relatively more ancient o However this tells us nothing about the absolute ages of the different rock layersHow old is that fossil o The half lives are a period of time required for half of the remaining parent atoms to decay or decompose to the daughter atoms or isotopes o Therefore when rocks are newly formed they are 100parent isotopes and after one half life has elapsed we will be left with a 11 ratio of parents to daughter isotopes and after another halflife we will be left with 25 parent and 75 daughter isotopes o This allows us to count how many half lives have elapsed and multiply by the length of the half live which gives us an estimat
More Less
Unlock Document
Subscribers Only

Only 80% of the first page are available for preview. Some parts have been intentionally blurred.

Unlock Document
Subscribers Only
You're Reading a Preview

Unlock to view full version

Unlock Document
Subscribers Only

Log In


OR

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


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