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Unit 7: Cellular Reproduction

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1 Unit 7: Cellular Reproduction
PART 1: Sexual vs. Asexual Reproduction Lessons 7.1 & 7.2

2 Unit 7 Table of Contents PART 1: Lesson 7.1 Asexual Reproduction
Lesson 7.2 Sexual Reproduction PART 2: Lesson 7.3 Chromosomes Lesson 7.4 The Cell Cycle Lesson 7.5 Mitosis Lesson 7.6 Cancer Lesson 7.7 Meiosis

3 Lesson 7.1 Asexual Reproduction Learning Objectives
I can define asexual reproduction and give examples. I can describe the differences between sexual and asexual reproduction

4 2 Types of Reproduction Asexual Reproduction Sexual Reproduction
involves only 1 parent offspring genetically identical to parent involves regular body cells its quick Sexual Reproduction involves 2 parents offspring genetic mix of both parents involves specialized sex cells its slow

5 Asexual Reproduction Asexual reproduction involves: One parent
No sex cells Offspring produced by cell division Offspring identical to parent (same DNA) Several types in prokaryotes, plants and animals

6 Types of Asexual Reproduction
Binary fission Budding Vegetative reproduction Cloning

7 1. Asexual Reproduction: Binary Fission
One parent cell splits into two genetically identical cells Prokaryotes only Examples: bacteria, Ecoli, pond critters

8 2. Asexual Reproduction: Budding
a new organism grows by cell division on the body of its parent the bud, or offspring is identical to the parent when it is large enough, the bud may break off and live on its own Examples: Yeast, Hydra, cactus

9 3. Vegetative Reproduction

10 4. Asexual Reproduction: Cloning
DNA from one organism is used to create a second organism that is an identical copy of the original. The copied material, which has the same genetic makeup as the original, is referred to as a clone. All forms of asexual reproduction create clones. Humans have successfully cloned various animals, starting with Dolly the sheep, but ethical laws have stopped scientists from attempting to clone humans. (But there are plenty of movies about it!)

11

12 Wishful Thinking!!!

13 Examples: Asexual Reproduction

14 Lesson 7.2 Sexual Reproduction Learning Objectives
I can define sexual reproduction and give examples. I can describe the differences between sexual and asexual reproduction

15 Sexual Reproduction Sexual reproduction involves: 2 parents
Sex cells: sperm and egg Sperm and egg join = fertilization Offspring look different from parent (mixed DNA) Sexual reproduction produces a greater chance of variation within a species than asexual reproduction would. This variation improves the chances that a species will adapt to its environment and survive.

16 Types of Sexual Reproduction
Conjugation Pollination External Fertilization Internal Fertilization

17 1. Sexual Reproduction: Conjugation
Bacterial conjugation: the transfer of genetic material between bacterial cells by direct cell-to-cell contact or by a bridge-like connection between two cells.

18 2. Sexual Reproduction: Pollination
Pollination occurs in plants. Pollen is taken from the male parts of one plant and delivered to the female parts of another plant, usually by an insect. The pollen then travels inside the flower and fertilizes an egg. The egg will grow into a seed which can become a new plant. Pollination also allows for genetic variation because the traits from two plants are mixed.

19 Pollination: Sexual Reproduction in Plants
Female Parts Male Parts (Pistil) pollen (male) + ovule (female) → single-celled zygote → multi-celled embryo (contained in a seed) → new individual

20 3. Sexual Reproduction: External Fertilization
The females lay the eggs in the water and the male squirts the sperm in the same area, usually in water. The sperm then swims towards the egg cell. External fertilization usually occur in fish and amphibians.

21 4. Sexual Reproduction: Internal Fertilization
Fertilization occurs inside the female. Internal fertilization occurs in mammals, insects, birds, reptiles. Mammals (humans, gorillas, lions, elephants, rats, zebras, and dolphins have live births) Insects, birds, reptiles lay eggs

22 Examples: Sexual Reproduction

23 Which is Better? It depends!
Asexual Reproduction advantages does not require special cells or a lot of energy can produce offspring quickly in a stable environment creates large, thriving population disadvantages limited ability to adapt face massive die-off if environment changes Sexual Reproduction advantages lots of variation within a species able to live in a variety of environmental settings able to adapt to changes in the environment disadvantages needs time & energy produce small populations

24 Types of Reproduction: Sexual vs. Asexual
Take a look at the table below. It summarizes the important differences between sexual and asexual reproduction. Sexual Reproduction Asexual Reproduction Number of Parents 2 parents 1 parent Genetic Variation Lots of genetic variation (a mix of traits from 2 parents) No genetic variation (the same traits from only 1 parent)

25 Which Type of Reproduction Is This?
Activity: Which Type of Reproduction Is This?

26 What type of reproduction is this??? Explain…

27 What type of reproduction is this??? Explain…

28 What type of reproduction is this??? Explain…

29 What type of reproduction is this??? Explain…

30 What type of reproduction is this??? Explain…

31 What type of reproduction is this??? Explain…

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33 What type of reproduction is this??? Explain…

34 What type of reproduction is this??? Explain…

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36 What type of reproduction is this??? Explain…

37 What type of reproduction is this??? Explain…

38 What type of reproduction is this??? Explain…


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