Reproduction Review

Reproduction Test Review with answers here!


  

Gametes are reproductive cells or sex cells.
The male gamete is sperm, the female gamete is ova or eggs.
Haploid cells are sperm and ova and have 23 chromosomes.
Haploid cells reproduce using MEIOSOS and result in unique cells than may one day become humans. Meiosis takes one diploid cell and rpoduces 4 haploid cells.

Diploid cells are body cells like blood cells and skin cells and have 23 pairs of chromosomes or 46.
Diploid cells reproduce using MITOSIS and result in 2 exact replicas or identical cells.

Asexual vs Sexual, Mitosis and Meiosis

2 NOTES

Key Concepts

Vocabulary

Key Concepts

After this lesson, students should understand the Key Concepts and be able to answer these questions. Have students write each question in their Science Journals. Revisit each question as you cover its relevant content.

Vocabulary

Deriving a Definition

1. Write the terms sexual reproduction and asexual reproduction on the board.

2. Ask: What is the definition of sexual reproduction?

Sexual reproduction is a type of reproduction in which the genetic materials from two different cells, in the form of an egg and a sperm, combine to produce an offspring with a unique genetic code.

3. Tell students that the prefix a- means “without” or “not.” Then guide students as they suggest characteristics of asexual reproduction.

4. Have students use these characteristics to write a definition of asexual reproduction in their own words in their Science Journals.

5. Tell students that the lesson’s other vocabulary words are examples of different kinds of asexual reproduction. Have students write these words in their Science Journals, followed by the definition.

Asexual or Sexual
Mitosis and Meiosis

Complete the the table below using the slides below.

Today's Powerpoint

Disagree. Asexual reproduction occurs in unicellular and multicellular organisms.

2 NOTES

Plants on Plants ?

Leveling Key

Plants on Plants?

About the Photo The photo shows a type of asexual reproduction called vegetative reproduction. The light blue structure with a zigzag edge is part of a leaf from a kalanchoe plant. The darker blue structures growing along the edge of the leaf are tiny plantlets. Each plantlet can grow into a new kalanchoe plant.

Guiding Questions

How did the tiny plants in the photo get there?

Students might propose different answers. Explain that the plants grew on the leaf through a process called vegetative reproduction.

Only one parent is involved in vegetative reproduction. Is the kalanchoe plant an example of sexual or asexual reproduction?

Have students read the definition of asexual reproduction. Because there is only one parent, vegetative reproduction is an example of asexual reproduction.

What are some other examples of plants growing from plant parts?

Students might mention examples such as potatoes growing from a piece of potato and a violet leaf growing into a new plant.

Leveling Key

Approaching Level   On Level   Beyond Level   English-Language Learners

Plants on Plants?

Dr. Brad Mogen/Visuals Unlimited

Look closely at the edges of this plant’s leaves. Tiny plants are growing there. This type of plant can reproduce without meiosis and fertilization.

Only one parent produced offspring during this process.

2 NOTES

What is asexual reproduction ?

Teacher Demo

What is asexual reproduction?

14.B

After students read the first three paragraphs, use the following scaffolded questions to start a discussion to connect their experience in the Launch Lab to the lesson.

Guiding Questions

Where did the DNA come from that is in a small yeast cell attached to a larger yeast cell?

The smaller cell received its DNA from the larger cell through the asexual process of budding.

Key Concept Check Describe asexual reproduction in your own words.

Students’ descriptions may vary. Sample description: In asexual reproduction, only one parent is needed and meiosis and fertilization do not take place.

If an offspring is genetically identical to its parent, what type of reproduction took place? Explain how you know.

Accept reasonable explanations. Asexual reproduction took place. If it were produced by sexual reproduction, the offspring would have half its DNA from each parent and would not be identical to either one of them.

Teacher Demo

Modeling Asexual Reproduction Shape a stick of modeling clay into a ball. Have students observe the ball. Then divide the modeling clay and form four or more balls of more or less equal size.

1. Ask students to discuss ways that the smaller balls are similar to and different from one another and the parent ball.

2. Then have students compare the balls to the process of asexual reproduction.

What is asexual reproduction?

14.B

 

In asexual reproduction, one parent organism produces offspring without meiosis and fertilization. Because the offspring inherit all their DNA from one parent, they are genetically identical to each other and to their parent.

 

35 NOTES

Types of Asexual Reproduction

Fission

Visual Literacy : Figure 1

Mitotic Cell Division

Budding

Visual Literacy : Figure 3

Animal Regeneration

Visual Literacy : Figure 4

Vegetative Reproduction

Cloning

Visual Literacy : Figure 6

Animal Cloning

Visual Literacy : Figure 7

Advantages of Asexual Reproduction

Visual Literacy : Figure 8

Disadvantages of Asexual Reproduction

Differentiated Instruction

Differentiated Instruction

Differentiated Instruction

Teacher Demo

Reading Strategy

Fun Fact

Differentiated Instruction

Differentiated Instruction

Differentiated Instruction

Teacher Demo

Real - World Science

Fun Fact

Differentiated Instruction

Differentiated Instruction

Differentiated Instruction

Real - World Science

Fun Fact

Reading Strategy

Fun Fact

Types of Asexual Reproduction

After students read the first paragraph, connect all types of reproduction by asking the questions below.

Guiding Questions

What is reproduction?

Sexual and asexual reproduction are processes in which organisms make more of their own kind.

Why is it important for organisms in a species to reproduce?

If organisms in a species did not reproduce, the species would die out.

Fission

Review differences between prokaryotic and eukaryotic organisms so that students understand how those differences might affect reproduction. Use the questions below to assess students’ understanding.

Guiding Questions

What is different about the DNA in a prokaryotic cell and a eukaryotic cell?

DNA in a eukaryotic cell is contained in a nuclear envelope, and DNA in a prokaryotic cell is not.

Reading Check What advantage might asexual reproduction by fission have over sexual reproduction?

Reproduction by fission can produce multiple offspring in a short amount of time.

Visual Literacy: Figure 1

14.B

Have students compare the photomicrograph of the dividing E. coli with the diagram in Figure 1. Use the questions below to help students interpret the diagram and photomicrograph.

Ask: What do the red arrows in the diagram show?

They show that each drawing is a step in a process.

Ask: In the photo of the E. coli, what color is the DNA?

dark red

Ask: Visual Check What happens to the original cell’s chromosome during fission?

It is copied. Each copy is distributed to an offspring.

Mitotic Cell Division

Students may have difficulty understanding that mitotic cell division is different from fission. Tell students that fission occurs in prokaryotic cells, which have no nucleus. Mitotic cell division occurs in eukaryotic cells, which have a nucleus. Have students read the paragraph about mitotic cell division. Then use the following questions to check understanding.

Guiding Questions

What must take place after mitosis to produce offspring?

Cytokinesis (cell division) must divide the cytoplasm to produce two organisms from one.

Why can’t prokaryotes reproduce by mitosis?

Answers should reflect an understanding that mitosis is division of the nucleus. Prokaryotes have no nucleus.

How is mitotic cell division different from fission?

Answers should reflect an understanding that in fission, the DNA is copied, and the cell elongates and splits. In mitotic cell division, the nucleus divides in a complex process of mitosis, and then the cytoplasm divides.

Budding

Both mitotic cell division and budding form a new organism by mitosis and cell division. In mitotic cell division, a unicellular parent cell becomes two identical offspring. The parent cell no longer exists. In budding, a new organism grows on the body of its unicellular or multicellular parent. The parent remains and one offspring is produced. Use the following questions to check understanding.

Guiding Questions

Why is budding a form of asexual reproduction?

A new organism forms without fertilization.

What two processes does a eukaryotic organism use to form a bud?

Mitosis and cell division are the two processes used to form a bud.

If an organism could reproduce by mitotic cell division and budding, which method would make more offspring after a certain time?

Sample answer: Mitotic cell division produces two offspring from one parent. Budding produces one offspring, so mitotic cell division would make more offspring.

Visual Literacy: Figure 3

14.B

When looking at Figure 3 photographs, students’ attention may be focused on the tentacles at the top of the organisms in the photos. Students may not notice the bud forming on the right side of the hydra’s body. Use the following questions to help students understand the photos.

Ask: Where is the bud starting to form in the photo at the left?

Along the right side of the hydra’s body.

Ask: How has the bud changed between the two photos?

The bud has changed from a bump to a small hydra.

Ask: Why is the bud genetically identical to the parent?

Answers should reflect an understanding that the bud grew out of the parent as an extension of the body through mitosis and cell division.

Animal Regeneration

14.B

In animal regeneration, a new organism grows from a part or piece that has been removed from the parent’s body. Have students read about animal regeneration. Then use the following questions to check understanding.

Guiding Questions

How does a new organism grow in regeneration?

Answers should reflect an understanding that a part or piece of the parent organism grows into a new organism.

Reading Check What is true of all cases of asexual reproduction?

The offspring is genetically identical to other offspring and to the parent.

Why is regeneration in which an organism grows or repairs a part of its own body not considered reproduction?

Growing or repairing a part of its body does not result in a new organism.

Visual Literacy: Figure 4

14.B

Have students compare the pictures of regeneration in Figure 4 with the dividing E. coli in Figure 1. Use the questions below to help students interpret the diagram and photomicrograph.

Ask: What do the red arrows in Figure 4 show?

The arrows show the location of the head end and the tail end of the planarian after it is cut in two and regeneration has taken place.

Ask: What happens to the head end of the planarian?

The head end grows a new tail.

Ask: What happens to the tail end of the planarian?

The tail end grows a new head.

Vegetative Reproduction

Have students read about vegetative reproduction and look at Figure 5. Then ask the following questions to check understanding.

Guiding Questions

How is the process of vegetative reproduction similar to animal regeneration?

In both types of asexual reproduction, a new organism grows from a part of a parent organism.

Visual Check Which plants in Figure 5 are the parent plants?

The large strawberry plants at the top of the photo are the parent plants.

Cloning

14.B

As students read about cloning, make sure they understand that cloning has been used to produce many of the fruits and vegetables that people eat. Then check their understanding with the following questions.

Guiding Questions

What part of a multicellular organism is used for cloning?

A cell or a cluster of cells from a multicellular organism is used for cloning. Students also might mention cells from the meristem in plants.

How is cloning similar to other types of asexual reproduction?

Sample answer: Cloning is similar to other types of asexual reproduction in that it uses cells from a multicellular parent and produces identical offspring.

What are the advantages of using cloning instead of vegetative reproduction for growing plants?

Plants can be produced from disease-free tissue in a parent with desirable traits that has become diseased.

Visual Literacy: Figure 6

14.B

Use Figure 6 to help students visualize the process of plant cloning. Make sure students understand that each cell removed from the carrot has the same chromosomes and produces an identical plant.

Ask: Why do the arrows form a circle?

The arrows show the sequence in plant cloning, which is a life cycle that starts with a mature carrot plant that is used to reproduce many new plants, which will grow into mature carrot plants.

Ask: What happens to cells taken from the carrot?

The cells are given nutrients. They divide and grow into new plants.

Ask: What processes do the cells use to grow?

mitosis and cell division

Animal Cloning

14.B

As students read the paragraphs about animal cloning, have them make connections to other types of asexual reproduction.

Guiding Questions

What is a potential use of animal cloning?

Possible answer: Cloning might help save some animals from extinction.

Key Concept Check Compare and contrast the different types of asexual reproduction.

fission: cell division in prokaryotes; mitotic cell division: cell division in unicellular eukaryotes; budding: an offspring grows on the body of the parent; regeneration: an animal grows from a piece of its parent; vegetative reproduction: a plant grows from a part of a parent plant; cloning: identical individuals grow from a cell or from a cluster of cells taken from a multicellular organism

Do Dolly and Sheep Z have the same DNA? Explain your answer.

No. The embryo that became Dolly contains DNA from another sheep. This DNA replaced the DNA in Sheep Z’s egg.

Visual Literacy: Figure 7

14.B

Use the diagram portion of Figure 7 to help students understand the process used in animal cloning. Make sure students understand that the cell removed from Sheep X contains chromosomes that are identical to other cells in Sheep X. All the chromosomes from Sheep Z are removed from its egg.

Ask: Why is the cell removed from Sheep X not an egg cell?

If it were an egg cell, it would only have half the chromosomes it needs to become an embryo.

Ask: Why was the DNA removed from Sheep Z’s egg cell?

If it had been left in the egg cell, the cell would have had too many chromosomes when it was fused with the cell from Sheep X.

Advantages of Asexual Reproduction

As students read about the advantages of asexual reproduction, have them connect the diagram of crabgrass with the photo.

Ask: Key Concept Check How is asexual reproduction beneficial?

Asexual reproduction enables organisms to reproduce without finding a mate. It also enables some organisms to rapidly produce a large number of offspring.

Visual Literacy: Figure 8

Have students study the underground portion of the plant shown.

Ask: Why is it difficult to keep crabgrass out of a flower bed or vegetable garden?

Rhizomes allow crabgrass to spread quickly into the area and are difficult to keep out. Removing all of them is difficult without also harming the flowers or vegetables.

Disadvantages of Asexual Reproduction

14.B

After students read about the disadvantages of asexual reproduction, use the following questions to check understanding.

Guiding Questions

Why is genetic variation important?

Genetic variation can give a population of organisms a better chance of survival if the environment changes or if a disease works its way through the population.

How is asexual reproduction a disadvantage?

Offspring are identical to their parent, so the population would have no genetic variation. A harmful mutation would be passed on to all offspring.

Under what circumstances do you think the disadvantages of asexual reproduction are more important than the advantages? Explain your answer.

Students might propose that the disadvantages are more important when the environment changes because none of the organisms may be able to survive a disease or reproduce.

Differentiated Instruction

Budding Babies Have students work in pairs to draw a cartoon showing two hydras each starting to form a bud. Students should include caption bubbles in their cartoon to indicate a conversation between the hydras that is humorous but still scientifically accurate.

Differentiated Instruction

Why can’t we regenerate? Have students research the types of animals that can reproduce through regeneration, such as sea stars, sea urchins, sea cucumbers, sponges, and planarians. Once students know more about the nature of these animals, ask them to write a paragraph explaining why they think humans cannot reproduce through regeneration.

Differentiated Instruction

Compare Drawings Have student groups draw pictures of organisms that are reproducing by fission, mitotic cell division, and budding. Then have students label their drawings and write captions that name and describe the type of asexual reproduction. Encourage students to include ways the three types of reproduction are different.

Teacher Demo

Too Many Bacteria To demonstrate how quickly bacteria can reproduce by fission, draw a cell on the board. Tell students that, under the right conditions, the cell divides every 30 minutes. Draw two cells below the original cell, then four cells below the two cells, and so on. Write 30 minutes next to the two cells. Write 60 minutes next to the four cells. Work with students to demonstrate how many bacteria will be in food at 3 P.M. if one cell entered the food at noon.

Reading Strategy

Matching Have students work in pairs. Give each pair six index cards. Have one student write one of the three types of asexual reproduction on each of three cards. Have the second student reread the text and write a description of the reproduction process on the other three cards. Have students shuffle the cards and then choose one. The student who did not write the card should match it with its counterpart.

Fun Fact

Yeast and Bread When yeast cells are mixed with flour, sugar, and water, they begin to reproduce. Yeast obtain energy by fermenting sugar, a process which produces carbon dioxide and alcohol. The carbon dioxide gas causes the bread dough to rise. The alcohol evaporates during baking.

Differentiated Instruction

Comparing Regeneration and Vegetative Reproduction Have pairs of students create a graphic organizer that compares animal regeneration and vegetative reproduction. Then have students share their graphic organizer with other pairs.

Differentiated Instruction

Is it reproduction? Have student groups create humorous stories about sea stars. One sea star loses an arm with a part of the central disk. The other sea star loses an arm without a part of the central disk. The story should explain the difference between animal regeneration and the regeneration of missing body parts. Encourage students to draw pictures to accompany their story.

Differentiated Instruction

14.B

Before and After Have students draw a picture of an animal before and after regeneration of new organisms and a picture of a plant before and after vegetative reproduction. Then have students label their drawings with the type of asexual reproduction represented. Encourage students to use oral language to explain each type of asexual reproduction in their drawings.

Teacher Demo

14.B

Growing More Plants A couple of weeks before class, remove one leaf and its leaf stem (or petiole) from an African violet where it connects to the plant. Suspend the cut end of the leaf stem in water without getting the leaf wet.

1. Ask: What happened to the leaf stem?

It has grown roots.

2. Ask: What will happen if you plant the leaf stem in soil?

It will grow into a plant with many leaves.

3. Ask: How many new plants can be grown from the parent plant?

Each leaf stem can grow into a new plant.

4. Make sure students understand by having them explain in their own words that this is an example of vegetative reproduction and all the new plants that grow will be genetically identical to the parent plant.

Real-World Science

Pulling Dandelions Some people don’t want to harm the environment by using herbicides, so they pull dandelions to remove them. However, if even a tiny piece of root is left in the ground, it can grow into a new dandelion plant.

Fun Fact

A Grove of Identical Trees Some species of trees, such as the aspen, have root systems that produce shoots that become new aspen trees. A grove of aspen trees in Utah contains approximately 47,000 genetically identical trees.

Differentiated Instruction

Cloning Words Have pairs of students reread the text about plant and animal cloning and make a list of all the science words used. Then have students use their own words to write a definition of each word and organize the words in a graphic organizer.

Differentiated Instruction

Cloning Directions Have students work in groups to write a set of directions for cloning a plant and a set of directions for cloning an animal.

Differentiated Instruction

My Journal Have students write a short journal entry describing what they learned about cloning that they didn’t know before reading this lesson.

Real-World Science

Bananas Banana plants are not grown from seeds. New banana plants are grown by vegetative reproduction, but mutations and disease have caused problems for farmers. Now farmers can buy banana tissue cultures that can produce many healthy plants.

Fun Fact

The Same but Different? The first cloned cat did not look exactly like its parent. Although animal clones contain identical DNA, clones of animals can look slightly different and have different behaviors from the parent. The differences are due to the deactivation of some genes during development.

Reading Strategy

Outline Have pairs of students create a graphic organizer to help them identify and remember the advantages and disadvantages of asexual reproduction. Encourage students to share their graphic organizers and make revisions if necessary.

Fun Fact

Asexual Seeds? Some plants, such as dandelions, can produce seeds without fertilization. This is a type of asexual reproduction called apomixis. This gives dandelions the advantages of asexual reproduction. At the same time, it has the advantage of its seeds being dispersed by wind, which is usually an advantage of sexual reproduction.

Types of Asexual Reproduction

14.B

There are many different types of organisms that reproduce by asexual reproduction, including fungi, bacteria, protists, plants, and animals.

Fission

Recall that prokaryotes have a simpler cell structure than eukaryotes. A prokaryote’s DNA is not contained in a nucleus. For this reason, mitosis does not occur and cell division in a prokaryote is a simpler process than in a eukaryote.

Cell division in prokaryotes that forms two genetically identical cells is known as fission.
 

Fission begins when a prokaryote’s DNA molecule is copied. Each copy attaches to the cell membrane. Then the cell begins to grow longer, pulling the two copies of DNA apart. At the same time, the cell membrane begins to pinch inward along the middle of the cell. Finally the cell splits and forms two new identical offspring. The original cell no longer exists.

As shown in Figure 1, E. coli, a common bacterium, divides through fission. Some bacteria can divide every 20 minutes. At that rate, 512 bacteria can be produced from one original bacterium in about three hours.

 

Reproduction by fission can produce multiple offspring in a short amount of time.

(r) CNRI/Photo Researchers

Figure 1 Bacteria can divide very rapidly through fission.

 

It is copied. Each copy is distributed to an offspring.

Mitosis Cell Division

Many unicellular eukaryotes reproduce by mitotic cell division. In this type of asexual reproduction, an organism forms two offspring through mitosis and cell division. In Figure 2, an amoeba’s nucleus has divided by mitosis. Next, the cytoplasm and its contents divide through cytokinesis and two new amoebas form.

Budding

In budding, a new organism grows by mitosis and cell division on the body of its parent. The bud, or offspring, is genetically identical to its parent. When the bud becomes large enough, it can break from the parent and live on its own. In some cases, an offspring remains attached to its parent and starts to form a colony.
Figure 3 shows a hydra in the process of budding. The hydra is an example of a multicellular organism that can reproduce asexually. Unicellular eukaryotes, such as yeast, can also reproduce through budding, as you saw in the Launch Lab.

(l and r) Biophoto Associates/Photo Researchers

Figure 3 The hydra bud has the same genetic makeup as its parent.

 Aninal Regeneration

Another type of asexual reproduction, regeneration, occurs when an offspring grows from a piece of its parent. The ability to regenerate a new organism varies greatly among animals.

Producing New Organisms Some sea stars have five arms. If separated from the parent sea star, each arm has the potential to grow into a new organism. To regenerate a new sea star, the arm must contain a part of the central disk of the parent. If conditions are right, one five-armed sea star can produce as many as five new organisms.

Sea urchins, sea cucumbers, sponges, and planarians, such as the one shown in Figure 4, can also reproduce through regeneration. Notice that each piece of the original planarian becomes a new organism. As with all types of asexual reproduction, the offspring is genetically identical to the parent.

 

The offspring is genetically identical to other offspring and to the parent.

Figure 4 A planarian can reproduce through regeneration.

Producing New Parts When you hear the term regeneration, you might think about a salamander regrowing a lost tail or leg. Regeneration of damaged or lost body parts is common in many animals. Newts, tadpoles, crabs, hydra, and zebra fish are all able to regenerate body parts. Even humans are able to regenerate some damaged body parts, such as the skin and the liver. This type of regeneration, however, is not considered asexual reproduction. It does not produce a new organism.

Vegetative Reproduction

Plants can also reproduce asexually in a process similar to regeneration. Vegetative reproduction is a form of asexual reproduction in which offspring grow from a part of a parent plant.

For example, the strawberry plants shown in Figure 5 send out long horizontal stems called stolons. Wherever a stolon touches the ground, it can produce roots. Once the stolons have grown roots, a new plant can grow—even if the stolons have broken off the parent plant. Each new plant grown from a stolon is genetically identical to the parent plant.
 

Vegetative reproduction usually involves structures such as the roots, the stems, and the leaves of plants. In addition to strawberries, many other plants can reproduce by this method, including raspberries, potatoes, and geraniums.

Wally Eberhart/Visuals Unlimited

The large strawberry plants at the top of the photo are the parent plants.

Cloning

Fission, budding, and regeneration are all types of asexual reproduction that can produce genetically identical offspring in nature. In the past, the term cloning described any process that produced genetically identical offspring. Today, however, the word usually refers to a technique developed by scientists and performed in laboratories.

Cloning is a type of asexual reproduction performed in a laboratory that produces identical individuals from a cell or from a cluster of cells taken from a multicellular organism. Farmers and scientists often use cloning to make copies of organisms or cells that have desirable traits, such as large flowers.
 

 

Figure 6 New carrot plants can be produced from cells of a carrot root using tissue culture techniques.
 

Animal Cloning In addition to cloning plants, scientists have been able to clone many animals. Because all of a clone’s chromosomes come from one parent (the donor of the nucleus), the clone is a genetic copy of its parent. The first mammal cloned was a sheep named Dolly. Figure 7 illustrates how this was done.
 

Scientists are currently working to save some endangered species from extinction by cloning. Although cloning is an exciting advancement in science, some people are concerned about the high cost and the ethics of this technique. Ethical issues include the possibility of human cloning. You might be asked to consider issues like this during your lifetime.

 

fission: cell division in prokaryotes; mitotic cell division: cell division in unicellular eukaryotes; budding: an offspring grows on the body of the parent; regeneration: an animal grows from a piece of its parent; vegetative reproduction: a plant grows from a part of a parent plant; cloning: identical individuals grow from a cell or from a cluster of cells taken from a multicellular organism

(l) Roslin Institute

Figure 7 Scientists used two different sheep to produce the cloned sheep known as Dolly.

Advantages of Asexual Reproduction

What are the advantages to organisms of reproducing asexually? Asexual reproduction enables organisms to reproduce without a mate. Recall that searching for a mate takes time and energy. Asexual reproduction also enables some organisms to rapidly produce a large number of offspring. For example, the crabgrass shown in Figure 8 reproduces asexually by underground stems called stolons. This enables one plant to spread and colonize an area in a short period of time.

\

Asexual reproduction enables organisms to reproduce without finding a mate. It also enables some organisms to rapidly produce a large number of offspring.

(l) Mark Steinmetz

Figure 8 Crabgrass can spread quickly because it reproduces asexually.

Disadvantages of Asexual Reproduction

Although asexual reproduction usually enables organisms to reproduce quickly, it does have some disadvantages.

Asexual reproduction produces offspring that are genetically identical to their parent. This results in little genetic variation within a population.

Why is genetic variation important? Recall that genetic variation can give organisms a better chance of surviving if the environment changes. Adaptation is possible.
 

Another disadvantage of asexual reproduction involves genetic changes, called mutations, that can occur. If an organism has a harmful mutation in its cells, the mutation will be passed to asexually reproduced offspring. This could affect the offspring’s ability to survive.

 

You probably know that plants can grow from seeds. But you might be surprised to learn that other parts of plants can grow and produce a new plant.
 

(tl) sciencephotos / Alamy, (tr) DEA/G.CIGOLINI/Getty Images, (b) Jerome Wexler / Photo Researchers, Inc.

 

Answers will vary, but students should describe one type of vegetative reproduction.

Lesson Review

Visual Summary

In asexual reproduction, offspring are produced with mitosis.

Dr. Brad Mogen/Visuals Unlimited

Cloning is one type of asexual reproduction.

Roslin Institute

Asexual reproduction enables organisms to reproduce quickly.

Mark Steinmetz

Lesson Assessmen14.B

Use Vocabulary

1. In ________ ________, only one parent organism produces offspring.

asexual reproduction

2. Define the term cloning in your own words.

Sample answer: Cloning is the use of an organism’s genetic information in a laboratory to create offspring genetically identical to a multicellular parent.

3. Use the term regeneration in a sentence.

Sample answer: The small pieces of the planarian grew into new organisms through regeneration.

Understand Key Concepts

4. State two reasons why asexual reproduction is beneficial.

Organisms do not need a mate, and organisms can produce many offspring.

5. Which is an example of asexual reproduction by regeneration?

      A.cloning sheep

      B.lizard regrowing a tail

      C.sea star arm producing a new organism

       D.strawberry plant producing stolons

6. Construct a chart that includes an example of each type of asexual reproduction.

Answers may vary.

7. Tissue culture is an example of which type of reproduction?

     A.budding

     B.cloning

      C.fission

      D.regeneration

8. Which type of asexual reproduction is shown in the figure below?

     A.budding

     B.cloning

     C.fission

     D.regeneration

9. A bacterium can reproduce by which method?

     A.budding

     B.cloning

     C.fission

     D.regeneration

Interpret Graphics
 

10. Examine the diagram below and write a short paragraph describing the process of tissue culture.

Sample answer: Cells are taken from a carrot and grown in a suspension. The cells divide and grow until they become young plants. The young plants can be planted in soil and eventually develop into mature plants.

11. Organize Copy and fill in the graphic organizer below to list the different types of asexual reproduction that occur in multicellular organisms.

Any order: cloning, regeneration, budding, and vegetative reproduction

 

Answers will vary. Example: Vegetative reproduction is advantageous for the crabgrass because the crabgrass can reproduce asexually, so it can reproduce and colonize an area quickly. The stolons are able to take root even if they have been separated from the parent plant, so the survival of the new plant does not depend on the survival of the parent plant.

 

Bill Coster/Getty Images

No, all living things do not have two parents. Some organisms reproduce by asexual reproduction, and only one parent is needed for this process.

Copyright © 2011-2012 The McGraw-Hill Companies. All Rights Reserved.
Texas Essential Knowledge and Skills Copyright © 2011. Texas Education Agency. All Rights Reserved.

Sexual Reproduction
Results in increasing genetic diversity of the offspring

Characterized by two processes:

meiosis, halving of the number of

chromosomes

fertilization, combination of two

gametes and the restoration of the

original number of chromosomes

During meiosis, chromosomes usually

cross over = genetic recombination.

Primary method of reproduction for

 

the vast majority of visible

organisms, including almost

all animals and plants.

 

 

Spider Mating Dance 


Mitosis describes the process by which the nucleus of a

cell divides to create two new nuclei, each containing an

identical copy of DNA.


Almost all of the DNA duplication in your body is carried out through mitosis.

Body cells like blood cells and skin cells aare created by mitosis.


Great Video about Mitosis and Meiosis

Click Here to learn more about Mitosis and Meiosis



Meiosis, as described above, is the process by which

certain sex cells are created. If you're male, your body uses meiosis to

create sperm cells; if you're female, it uses meiosis to create egg cells.

Others cells in your body contain 46 chromosomes: 23 from your father and 23 from your mother. Diploid Cells!

Your egg (or sperm) cells contain only half that number (Haploid Cells) —a total of 23 chromosomes. When an egg and sperm unite to make a fertilized egg, the chromosomes add up to equal 46.