Bio; Lecture 17; Animal Evolution

Bio; Lecture 17; Animal Evolution - Principles of Biology 2...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Principles of Biology 2 BIO U103 2/21/07 Multicellularity o The animal kingdom evolved from a Colonial flagellated protest o This ancestor most likely lived over 700 million years ago in Precambrian era o Choanoflagellates Probably gave rise to the porifera phylum They both share choanocyte cells Diverged into parazoa (no tissue) and eumetazoa (true tissue) o Monophyletic If all animal lineages were traced back to their origin, there would be only one common ancestor—making them monophyletic o Advantages and disadvantages of multicellularity Multicellularity produces macroscopic organisms Animals got bigger and bigger over time The eukaryotic cell is 10 times larger than the first prokaryotes There is a threshold Below this size threshold, organisms must be unicellular Above, they must be multicellular Advantages of having a relatively large size . Larger volume buffers organisms against environmental
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 05/26/2008 for the course BIO 103 taught by Professor Potts-santone during the Spring '07 term at Northeastern.

Page1 / 3

Bio; Lecture 17; Animal Evolution - Principles of Biology 2...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online