Question

6-23 Sat Jan 19 1. While rotifers are a model organism for our purposes, what about rotifer anatomy indicates that they could not have been a predator species that may have led to the first origin of multicellularity? As a hint, think about the anatomical characteristics of animals in the Kingdom Animalia (the Kingdom that rotifers belong too). (2 Marks - Maximum 100 Words) Record your answer below. Use as much space as you require, however keep the word limit in mind Once the word limit for a question is reached, nothing written past that point will be marked. 2. In Will Ratcliff's multicellular yeast strain called S. cerevisiae, how did they select for multicellular yeast? Second, how did they select for larger multicellular yeast (2 Marks Maximum 100 Words) Record your answer below: Use as much space as you require, however keep the word limit in mind Once the word limit for a question is reached, nothing written past that point will be marked 3. Rotifers have two unique organs: the wheel organ and the trophi. Read the section of your textbook (by Campbell) on Rotifers and explain the function of these organs. (2 Marks- Maximum 100 Words) Record your answer below Use as much space as you require, however Keep the word limit in mind Once the word limit for a question is reached, nothing written past that point will be marked

Answer 1

1: Rotifers are protostomes and have pseudocoelom. They are not a monophyletic group and are supposed to have evolved through a process of development of simple body organization from the complex one. It is supposed to have more than one group of animals with a true coelom as ancestors. Presence of cuticle in rotifers makes them related to arthopods. Rotifers have constant number of cells in their body and exhibit growth by increase in cell size only. Cell division is stopped after embryonic development.