The Life Cycle Biology Worksheet (Page 2 of 4) in pdf

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Life cycles:

Because there are two divisions in meiosis, a zygote undergoing meiosis always yields four daughter

cells.

If the parents are genotypically distinct (i.e., not clones), it is highly likely that none of the daughter

cells is genetically identical to either parent, and that any two daughter cells are identical (this is why,

from an evolutionary point of view, sexual reproduction is "better" than asexual [clonal]

reproduction).

We have now linked two fundamental stages of a life cycle involving sexual reproduction:

SYNGAMY

GAMETES

ZYGOTE

MEIOSIS

This is the most simple life cycle in which sexual reproduction occurs. A species characterized solely

by these two phases would be a unicellular algae.

Many plants are, however, multicellular, that is their body is composed of numerous cells. Such

multicellular organism forms through the proliferation of cells. Imagine that the cells resulting from

meiosis did not function as gametes, but instead remained vegetative. How would you develop a

multicellular organism from these cells. If these cells merely aggregated, the result may seem like a

multicellular organim, but would actually be a colonial organism composed of unicellular individuals.

A multicellular organism is obtained by the cells undergoing cell division.

Would meiosis be the mode of cell division? ______. Justify your answer:

______________

__________________________________________________________________________

The proliferation of cells relies on the duplication of the parental cell. What is needed for the

daughter cells to be genetically identical to the parental cell, i.e., for them to have the exact same

number of chromosomes as in the parent?

________________________________________

__________________________________________________________________________

How is this mode of cell division called? __________________________________________

For a cell to undergo mitosis, does it have to be a diploid cell? ___. Justify: _______________

__________________________________________________________________________

The Life Cycle Biology Worksheet Page 2