chap 17 notes

chap 17 notes - Chapter 17 Cleavage, a series of rapid cell...

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

View Full Document Right Arrow Icon
Chapter 17 Cleavage, a series of rapid cell divisions without growth, provides cellular building blocks for development Learning Objective 6 * Contrast early development, including cleavage in the echinoderm (or in amphioxus), the amphibian, and the bird, paying particular attention to the importance of the amount and distribution of yolk Invertebrates and Simple Chordates * Have isolecithal eggs (small amounts of yolk evenly distributed through cytoplasm) * undergo holoblastic cleavage * i.e. division of entire egg * radial or spiral cleavage * radial – eg Deuterostomes (sea stars and chordates); two cells split into four equal cells, four into eight etc each at right angles to the other; Cleavage in Sea Stars (radial and holoblastic) (Fig 50-3) Cleavage in Amphioxus (Fig 50-4) Spiral Cleavage * Spiral cleavage – Proteosomes * e.g. annelids and mollusks * After first two divisions – plane of cytokinesis is diagonal to polar axis * Results in a spiral arrangement of cells *
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 01/24/2012 for the course 832 335 taught by Professor Abruzzi during the Spring '10 term at Rutgers.

Page1 / 2

chap 17 notes - Chapter 17 Cleavage, a series of rapid cell...

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