Chapter Menu Lesson 1:Sexual Reproduction and MeiosisSexual Reproduction and Meiosis Lesson 2:Plant ReproductionPlant Reproduction Lesson 3:Animal ReproductionAnimal

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Lesson 1: Sexual Reproduction and Meiosis

Lesson 2: Plant Reproduction

Lesson 3: Animal Reproduction

Lesson 4: Asexual Reproduction

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sexual reproduction

egg

sperm

fertilization

zygote

3.1 Sexual Reproduction and Meiosis

meiosis

diploid

haploid

What is sexual reproduction?

• Reproduction in organisms produces new offspring.

• Sexual reproduction is the production of an offspring that results when the genetic materials from two different cells combine.


What is sexual reproduction? (cont.)

• Half the genetic material in sexual reproduction is contained in:

– an egg cell

– a sperm cell

• In a process called fertilization, the sperm and egg cells fuse together forming a zygote.


Meiosis and Fertilization

Advantages of Sexual Reproduction

• Genetic variation

– Variety of genetic traits in a population of the same species

– Can help a species survive changes in environmental conditions


Advantages of Sexual Reproduction (cont.)

• Selective breeding

– Male and female organisms with certain preferred traits are selected to be the parents of offspring with those preferred traits

– Produces groups of organisms with similar traits

– Reduces genetic variation


Disadvantages of Sexual Reproduction• Getting egg and sperm together for fertilization can

be difficult

• Time is needed for organisms to grow and develop before they can reproduce


Why is meiosis important?• Meiosis is cell division that produces sperm or eggs

from certain reproductive cells in an organism.

– Meiosis ensures that a species’ offspring inherit the correct chromosome number.

– Without meiosis, the chromosome number would double with each generation.


Maintaining Diploid Cells• A diploid cell in an organism contains pairs of homologous chromosomes

that equal the chromosome number of that organism’s species.

– A diploid human cell has 23 pairs of homologous chromosomes.

– Homologous chromosomes are similar, but not identical.


Creating Haploid Cells• A haploid cell contains one chromosome from each

homologous pair.


Creating Haploid Cells (cont.)


Phases of Meiosis I


Prophase I—Nuclear membrane breaks apart and chromosomes condense.

Metaphase I—Sister chromatids line up along the center of the cell. Cytoskeleton fibers attach to sister chromatids.

Phases of Meiosis I (cont.)


Telophase I—Nuclear membrane forms around each set of sister chromatids and the cytoplasm divides, forming two daughter cells.

Anaphase I—Sister chromatids move to opposite ends of the cell.

Phases of Meiosis II


Metaphase II—Chromosomes line up along the center of the cell.

Prophase II—Nuclear membrane breaks apart.

Phases of Meiosis II (cont.)


Anaphase II—Sister chromatids of each chromosome begin to separate and move to opposite ends of the cells.

Telophase II—A nuclear membrane forms around each set of chromatids, and the cytoplasm divides.

Comparison of Meiosis and Mitosis


Lesson 1 Review

What is the new cell that forms from fertilization called?

A sperm

B egg

C haploid

D zygote


A B C D

0% 0%0%0%

1. A

2. B

3. C

4. D

Lesson 1 Review

How many chromosomes from each homologous pair does a haploid cell contain?

A one

B two

C three

D four


A B C D

0% 0%0%0%

1. A

2. B

3. C

4. D

Lesson 1 Review

How many daughter cells are produced in meiosis?

A one

B two

C three

D four


A B C D

0% 0%0%0%

1. A

2. B

3. C

4. D

End of Lesson 1

spore

pollen grain

ovule

seed

angiosperm

stamen

anther

3.2 Plant Reproduction

filament

pistil

stigma

style

ovary

pollen tube

fruit

What is alternation of generations?

– One generation has primarily diploid cells, the other generation has only haploid cells.

– Organisms that alternate between diploid and haploid generations have an alternation of generations.

• Some organisms, including plants, have two life stages called generations.


What is alternation of generations? (cont.)


How do seedless plants reproduce?• Seedless plants, such as mosses and ferns, grow from

haploid spores, not seeds.

– Haploid spores that grow by mitosis and cell division into haploid plants.

– Fertilization results in a diploid zygote that grows by mitosis and cell division into the diploid generation.

– The diploid generation produces haploid spores by meiosis, and the cycle repeats.


How do seed plants reproduce?• Most of the land plants that cover Earth grew from

seeds—called seed plants.

– There are flowerless seed plants and flowering seed plants.

– The haploid generation is within diploid tissue.

– Separate diploid male and diploid female reproductive structures produce haploid sperm and haploid eggs.


The Role of Pollen Grains• A pollen grain forms from tissue in a male

reproductive structure of a seed plant.

• Pollination occurs when pollen grains land on a female reproductive structure of a plant of the same species.


The Role of Ovules and Seeds• The female reproductive structure of a seed plant

contains one or more ovules.

• After fertilization, a seed develops from the ovule.


Flowerless Seed Plant Reproduction• In flowerless seed plants—gymnosperms— the seeds

are not surrounded by a fruit.

– Cones are the male and female reproductive structures of conifers.

– Male cones produce pollen grains.

– Female cones produce eggs.

– Seeds form as part of the female cone.


Flowering Seed Plant Reproduction• Flowering seed plants—angiosperms—include most

of the plants you see.


Seed Plants

• Fruits and vegetables come from flowering seed plants.

Reproduction and the Flower• A typical flower has male and female reproductive

organs surrounded by petals.

• The stamen is the male reproductive organ.

• Pollen grains form at the tip of the stamen, in the anther.

• The filament is a long stalk that supports the anther and connects it to the base of the flower.


Reproduction and the Flower (cont.)

• The female reproductive organ of a flower is the pistil.

• Pollen can land at the tip of the pistil on the stigma, which is at the top of a long tube called the style.

• At the base of the style is an ovary containing one or more ovules which eventually will contain a haploid egg.


Reproduction and the Flower (cont.)


An Angiosperm’s Cycle 3.2 Plant Reproduction

Fruit and Seed Dispersal• Fruits and seed are important sources of food for

people and animals.

• Fruits and seeds can be dispersed by:

– Air currents

– Animals

– Water

– Gravity


What is the life cycle of a simple plant?

Lesson 2 Review

In alternation of generations, the haploid structures of the diploid generation produces daughter cells called what?

A zygotes

B spores

C pollen

D seeds


A B C D

0% 0%0%0%

1. A

2. B

3. C

4. D

Lesson 2 Review

What is an immature diploid plant that develops from the zygote of a seed plant called?

A embryo

B seed

C fruit

D stigma


A B C D

0% 0%0%0%

1. A

2. B

3. C

4. D

Lesson 2 Review

What is another name for a flowering seed plant?

A zygote

B conifer

C gymnosperm

D angiosperm


A B C D

0% 0%0%0%

1. A

2. B

3. C

4. D

End of Lesson 2

gonad

testes

ovary

metamorphosis

3.3 Animal Reproduction

– Ovaries are female gonads that produce egg cells.

Animal Reproductive Organs• Gonads are specialized organs that produce sperm or

eggs.

– Testes are male gonads that contain a network of coiled tubes in which sperm cells form.


Internal Fertilization• Internal fertilization happens inside the body of an

organism.

– Internal fertilization ensures that an embryo is protected and nourished until it leaves the female’s body.


• Examples

– Earthworms, spiders, insects, reptiles, birds, and mammals

External Fertilization• External fertilization occurs in the environment, outside

of an animal’s body.

– Most animals that reproduce using external fertilization do not care for the eggs or young.


• Examples

– Jellyfishes, clams, sea urchins, sea stars, many fish species, and amphibians

External Embryo Development• Animals whose embryos develop outside the mother are usually protected inside

an egg.


Metamorphosis• A developmental process in which the form of the body

changes as an animal grows from egg to adult


Internal Development• The embryos of some animals, including most

mammals, develop inside the mother.

– A tissue or organ transfers nourishment from the mother to the embryo.

– Other embryos—some snakes, insects, and fishes—develop in an egg with a yolk inside the mother.


Gestation• Gestation is the length of time between fertilization and

the birth of an animal.

• Gestation varies by species and usually relates to the size of the animal at birth—smaller animals have shorter gestation.


Lesson 3 Review

Where are sperm formed in male animals?

A eggs

B ovaries

C testis

D glands


A B C D

0% 0%0%0%

1. A

2. B

3. C

4. D

Lesson 3 Review

How is the embryo in an egg nourished?

A the outer covering

B an organ transfers nourishment from the mother

C fluid produced in glands near the testes

D the yolk


A B C D

0% 0%0%0%

1. A

2. B

3. C

4. D

Lesson 3 Review

What is the developmental process in which the form of the body changes as an animal grows from egg to adult?

A metamorphosis

B gestation

C fertilization

D internal development


A B C D

0% 0%0%0%

1. A

2. B

3. C

4. D

End of Lesson 3

asexual reproduction

fission

budding

regeneration

cloning

3.4 Asexual Reproduction

Asexual Reproduction• The production of offspring by one parent without a

sperm and an egg joining

• Results in offspring that are genetically identical to the parent organism


Advantages of Asexual Reproduction• No time or energy expended finding

a mate.

• Less time to produce offspring

• Parent and offspring are genetically identical—equally well-adapted to the same environmental conditions.


Disadvantages of Asexual Reproduction

• Lack of genetic variation.

• Harmful mutations in the cells of an organism will be passed to offspring


Types of Asexual Reproduction• Prokaryotes reproduce asexually by cell division

that does not involve mitosis.

• Eukaryotes reproduce asexually by mitosis and cell division.


Fission• Bacteria reproduce by a process called fission which

produces two genetically identical cells very rapidly.


Mitotic Cell Division• Some single-celled eukaryotes reproduce by mitotic cell

division—mitosis followed by cell division.

– Produces two identical cells.

– Each cell is an organism.


Budding• Asexual reproduction in which a new organism

forms on the parent organism

• The new organism—a bud—forms by mitosis and cell division, and eventually separates from the parent

• Example

– Some single-cell (yeast) and multicellular eukaryotes (hydra)


Plant Cuttings• If you cut a green stem from a houseplant and put it in

water, roots and leaves can grow, producing a new plant.

• Some plants propagate themselves asexually.

• Examples

– Strawberry plants and kalanchoe plants


Animal Regeneration• Some animals have cells that can change into

other cell types.

• Regeneration is asexual reproduction that produces new animals from pieces of an animal’s body.

• Regeneration is sometimes used to describe growth that replaces a missing part of an animal.


What is cloning?• Cloning refers to a method of asexual reproduction

developed by scientists and performed in laboratories.

• Cloning produces identical individuals from a cell or cells taken from a multicellular organism.


Plant Cloning


Animal Cloning• The first animal to be successfully cloned was a sheep

named Dolly, in 1996


Lesson 4 Review

What type of asexual reproduction involves reproduction by cell division only?

A fission

B budding

C regeneration

D cloning


A B C D

0% 0%0%0%

1. A

2. B

3. C

4. D

Lesson 4 Review

What type of asexual reproduction involves a new organism forming on the parent organism?

A mitotic cell division

B cloning

C regeneration

D budding


A B C D

0% 0%0%0%

1. A

2. B

3. C

4. D

Lesson 4 Review

What type of asexual reproduction involves producing a new animal from pieces of an animal’s body?

A plant cuttings

B cloning

C regeneration

D budding


A B C D

0% 0%0%0%

1. A

2. B

3. C

4. D

End of Lesson 4

Chapter Resources Menu

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Chapter Assessment

California Standards Practice

Concepts in Motion

Image Bank

Science Online

Virtual Lab

BrainPOP

What is the name for the process of a sperm cell and an egg cell fusing together?

A sexual reproduction

B fertilization

C meiosis

D pollination

Chapter Assessment 1

A B C D

0% 0%0%0%

1. A

2. B

3. C

4. D

What is one advantage of sexual reproduction?

A produces many offspring

B offspring are genetically identical

C offspring have more genetic variation

D can produce offspring quickly


A B C D

0% 0%0%0%

1. A

2. B

3. C

4. D

Where are pollen grains formed?

A anther

B ovule

C testes

D pollen tube


A B C D

0% 0%0%0%

1. A

2. B

3. C

4. D

What are animal reproductive organs called?

A zygotes

B gonads

C embryos

D buds


A B C D

0% 0%0%0%

1. A

2. B

3. C

4. D

What is not an advantage of asexual reproduction?

A organism does not have to spend time and energy finding a mate

B can produce a number of offspring faster than with sexual reproduction

C offspring have more genetic variation

D parent and offspring are equally well adapted to the same environmental conditions


A B C D

0% 0%0%0%

1. A

2. B

3. C

4. D

What type of organism can reproduce asexually by regeneration?

A human

B sea star

C bacterium

D yeast

CA Standards Practice 1

SCI 2.a

A B C D

0% 0%0%0%

1. A

2. B

3. C

4. D

What flower structure becomes fruit surrounding the seed?

A stamen

B pollen tube

C ovary

D pistel


SCI 2.a

A B C D

0% 0%0%0%

1. A

2. B

3. C

4. D

What term describes the development of a ladybug larva to an adult ladybug?

A alternation of generations

B asexual reproduction

C metamorphosis

D mitotic cell division


SCI 2.a

A B C D

0% 0%0%0%

1. A

2. B

3. C

4. D

What type of seed plant does not produce flowers?

A seedless plants

B gymnosperms

C angiosperms

D strawberry plants


SCI 2.a

A B C D

0% 0%0%0%

1. A

2. B

3. C

4. D

How many times does division of the nucleus and cytokinesis happen in meiosis?

A one

B two

C three

D four


SCI 2.a

A B C D

0% 0%0%0%

1. A

2. B

3. C

4. D

Concepts in Motion 1

Meiosis and Fertilization

Concepts in Motion 2

Image Bank

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Chapter Menu Lesson 1:Sexual Reproduction and MeiosisSexual Reproduction and Meiosis Lesson 2:Plant ReproductionPlant Reproduction Lesson 3:Animal ReproductionAnimal