u7 l3 sexual & asexual reproduction
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ScienceFusion PowerNotes Grade 8 Sexual & Asexual ReproductionTRANSCRIPT
Unit 7 Lesson 3 Sexual and Asexual Reproduction
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Unit 7 Lesson 3 Sexual and Asexual Reproduction
Indiana Standards
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• 8.3.1 Explain that reproduction is essential for the continuation of every species and is the mechanism by which all organisms transmit genetic information.
• 8.3.2 Compare and contrast the transmission of genetic information in sexual and asexual reproduction.
• 8.3.3 Explain that genetic information is transmitted from parents to offspring mostly by chromosomes.
One Becomes Two
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What is asexual reproduction?
• Reproduction involves various kinds of cell division.
• Most single-celled organisms and some multicellular organisms reproduce asexually.
• In asexual reproduction, one organism produces one or more new organisms that are identical to itself.
Unit 7 Lesson 3 Sexual and Asexual Reproduction
What is asexual reproduction?
• The organism that produces the new organism or organisms is called a parent.
• Each new organism is called an offspring.
• The offspring produced by asexual reproduction are genetically identical to their parents.
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Unit 7 Lesson 3 Sexual and Asexual Reproduction
How do organisms reproduce asexually?• Organisms reproduce asexually in many ways.
• Prokaryotes, including bacteria, reproduce asexually by cell division.
• Some eukaryotes, including many multicellular organisms, reproduce asexually by more complex processes—types of cell division called mitosis.
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Unit 7 Lesson 3 Sexual and Asexual Reproduction
How do organisms reproduce asexually?• Binary fission is the form of asexual reproduction
in prokaryotes.
• Budding occurs when a bud grows on a full-sized organism.
• Budding is the result of mitosis.
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Unit 7 Lesson 3 Sexual and Asexual Reproduction
How do organisms reproduce asexually?• A spore is a specialized cell that can survive harsh
conditions.
• Spores are light and can be carried by the wind.
• Some plants can reproduce asexually by vegetative reproduction
• Vegetative reproduction happens through mitosis.
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Unit 7 Lesson 3 Sexual and Asexual Reproduction
Two Make One
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What is sexual reproduction?
• Most multicellular organisms can reproduce sexually.
• In sexual reproduction, two parents each contribute a sex cell to the new organism.
• Half the genes in the offspring come from each parent.
Unit 7 Lesson 3 Sexual and Asexual Reproduction
What is sexual reproduction?
• Males produce sex cells called sperm cells.
• Females produce sex cells called eggs.
• Sex cells are produced by meiosis.
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Unit 7 Lesson 3 Sexual and Asexual Reproduction
What is sexual reproduction?
• Sex cells have half of the set of genetic material found in body cells.
• A sperm and an egg join together in a process called fertilization.
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Unit 7 Lesson 3 Sexual and Asexual Reproduction
What is sexual reproduction?
• When an egg is fertilized by a sperm cell, a new cell, called a zygote, is formed. It has a full set of genetic material.
• The zygote develops into a new organism. It grows through mitosis.
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Unit 7 Lesson 3 Sexual and Asexual Reproduction
Unit 7 Lesson 3 Sexual and Asexual Reproduction
Odd Reproduction
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• Multicellular organisms can reproduce asexually.
• Some do this by parthenogenesis, in which the female produces young without fertilization.
• Other organisms reproduce asexually by regeneration.
• Other organisms reproduce asexually by fragmentation, in which segments fall off and become new organisms.
Added Advantage
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What are the advantages of each type of reproduction?• Asexual reproduction has its advantages.
• It allows an organism to reproduce very quickly, and ensures that any favorable traits the parent has are passed on to the offspring.
• Reproduction can occur without a partner, and all offspring can reproduce.
Unit 7 Lesson 3 Sexual and Asexual Reproduction
What are the advantages of each type of reproduction?• Sexual reproduction has its advantages.
• It increases genetic variation. Offspring have different traits, which improves the chance that at least some will survive.
• Some organisms can use both types of reproduction. This allows them to spread quickly, and adapt to changes in the environment as well.
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Unit 7 Lesson 3 Sexual and Asexual Reproduction