Post on 13-Jan-2016
Warm Up1. A particular species of shark normally reproduces sexually. In
captivity, it was found that a female could also reproduceasexually. One negative result from asexual reproduction is
(1) increased mutations(2) increased number of males produced (3) decreased number of eggs used (4) decreased variation within the species
2. When an organism is growing it needs to create new body cells from existing cells. A body cell can divide to create an identical copy of itself for this purpose. This process of cell division is called
(1) fertilization (2) mitosis (3) replication (4) gene splicing
3. Sexually reproducing organisms require gametes to pass on and combine their genetic information. Identify the male and female gamete in humans.
Male gamete __________________Female gamete________________
Announcements
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Why is it that organisms that reproduce sexually have so much
variety?
Why is it that organisms that reproduce sexually have so much
variety?Meiosis!
46
46 46
92
46
46 46
92
23 23 23 23
2 Forms of Cell Division
46
46 46
92
Mitosis
_____________
46
46 46
92
46
46 46
92
23 23 23 23
Meiosis
________
Mitosis
Mitosis- form of cell division that results in 2 daughter cells that are identical to the parent cell
Meiosis-_________________________________________________________________________________
Site of Meiosis___________________________
Genetic Information in Human Cells
Body Cells- 46 Gamete Cells- 23
How does meiosis lead to variationvariation in offspring?
How does meiosis lead to variationvariation in offspring?
Gene Sorting and Recombination!
Are each of these sperm genetically identical?
4
8
4 4
2 2 2 2
Are each of these sperm genetically identical?
4
8
4 4
2 2 2 2
No! This is calledGene Sorting
How does meiosis lead to variation in offspring?
Recombination- a process where parts of chromosomes are swapped during meiosis to increase variation
How does meiosis lead to variation in offspring?
Recombination- a process where parts of chromosomes are swapped during meiosis to increase variation
Stop and JotIdentify one process that occurs during
meiosis which increases variation. Explain how it increases variation.
Partner Practice
1. Meiosis occurs within structure(1) A (2) B (3) C (4) D
2. The body cells of a kangaroo contain 12 chromosomes. How many chromosomes would be present in a kangaroo cell produced by mitosis?(1) 3 (2) 6 (3) 12 (4) 24
3. The body cells of a kangaroo contain 12 chromosomes. How many chromosomes would be present in a kangaroo cell produced by meiosis?(1) 3 (2) 6 (3) 12 (4) 24
4. True or False?– A. Mitosis creates cells that have half of the normal
number of chromosomes _________– B. Meiosis is the process of cell division that is used
to create body cells _________– C. Daughter cells produced by meiosis are genetically
identical to their parent cells _________– D. The process of mitosis leads to increased genetic
variation among cells_________