U n i t 1Summary

essential question

How is the reproduction of cells

essential to the survival of

organisms?

TOPIC 1 .2:What are different ways that living things reproduce asexually?

•Bacteria reproduce by binary fission.

•All eukaryotic cells reproduce by the cell cycle.

•Yeasts reproduce by budding.

•Moulds reproduce using spores.

•Plants have many ways to reproduce asexually.

Key termsbinary fission cell cycle budding

spore vegetative propagation clone

TOPIC 1 .1 :Why is the reproduction of cells important?

•Reproduction ensures that life exists beyond its present generation.

•Reproduction transfers genetic information from parents to offspring.

Key termsasexual reproduction

sexual reproduction

DNA

chromosome

74 MhE • UnIT 1

Sample Material

TOPIC 1 .3 :how do living things sexually reproduce?

•Male and female reproductive cells combine to produce a zygote.

•Reproductive cells are formed by a cell-dividing process called meiosis.

•Development of the human zygote occurs in stages.

•Sexual reproduction takes many different forms.

Key termsgamete fertilization

haploid diploid

TOPIC 1 .4 :how does reproduction contribute to the variety of life on Earth?

•Asexual reproduction results in many genetically identical offspring in a short amount of time.

•Sexual reproduction results in genetically varied offspring.

Key termgenetic variation

UnIT 1 sUmmary • MhE 75

Sample Material

What Do You Know? Connecting to Concepts

Review

U n i t 1

Visualizing Ideas 1. Describe how the photo below

represents reproduction. In your description, include the following information:

• the type of reproduction that is represented, with reasons that support your statement

• what you know about the offspring based on this type of reproduction

2. Copy and complete the following concept map about reproduction.

o�spring results through

which is the joining of

which includes

Reproduction

can becan be

Using Key Terms 3. Develop a set of flash cards that could

be used to help you study asexual and sexual reproduction. Your flash cards should include the key terms listed below and any diagrams that illustrate each process.

• artificial • binary fission propagation

• biodiversity • budding

• cell cycle • egg

• eukaryote • fertilization

• gamete • genetic variation

• meiosis • mitosis

• prokaryote • sperm

• spore formation • zygote

Communicating Concepts 4. Make a sketch of a plant cell that shows

where the cell’s genetic information is found.

5. In what ways would your sketch in question 4 be different if you were making a sketch of an animal cell? In what ways would it be similar?

6. Explain how the following terms are related: DNA, chromosome, genetic material.

7. a) What is the name of the molecule that stores genetic information?

b) Why is it important that this molecule is duplicated during interphase of the cell cycle?

8. How does the DNA sequence of a parent bacterial cell compare to the DNA sequence of a daughter cell? Explain your answer.

9. Explain how genetic variation is important to the survival of a species.

76 MhE • Unit 1

Sample Material

10. In a little less than a month, your body replaces all the cells of your skin. Is this an example of mitosis in action? Explain.

11. Both mitosis and meiosis are required for humans to reproduce and develop.

a) What role does meiosis play? Why is it better suited for that role than mitosis?

b) What role does mitosis play? Why is it better suited for that role than meiosis?

12. Why is sexual reproduction an advantage for an organism? Describe two disadvantages that are also part of sexual reproduction.

13. Plants can reproduce asexually.

a) Describe one example of how a plant asexually reproduces.

b) Why is it considered asexual reproduction? What does it tell you about the genetic material of the new plant?

c) How do people such as farmers and gardeners use a plant’s ability to asexually reproduce? Use an example you have learned about in this unit, or one from your own experience.

14. Copy and complete the following table.

Question Mitosis Meiosis

How many cells are produced for every cell that begins?

How do parent and daughter cells compare to each other?

How do daughter cells compare to each other?

number of divisions of the nucleus?

Function

15. In three or four sentences, describe the major events that happen in the cell cycle.

a) Does every type of cell go through the cell cycle? Support your answer using examples.

b) Is the cell cycle exactly the same for every cell in a person’s body? Use examples to support your answer.

16. The cells that make up the body of a duck contain 80 chromosomes. How many chromosomes are in each of the following cells? Explain your answer for each. Use the terms “haploid” and “diploid” in your answers.

a) egg cell b) sperm cell c) zygote

What Can You Do? Connecting to Competencies

Developing Skills 17. Describe how you would design a model

to represent the process of binary fission. Your model can take any form you wish. For example, you could design it digitally or with materials found in the kitchen.

18. How are haploid cells different from diploid cells? What processes produce haploid and diploid cells?

19. You are working as a counsellor in a summer camp. Some of the buildings are old and the roofs leak. You notice dark, fuzzy-looking material that you think is mould growing in one of the buildings.

Develop an explanation for where the dark fuzzy growth might have come from, how it is growing, and why it may cause health problems. Make sure your explanation could be understood by people without a science background.

Unit 1 review • MhE 77

Sample Material

Unit 1 Review (continued)

20. Bacteria have both positive and negative influences in the food industry.

a) What are some of these negative and positive influences?

b) Develop a hypothesis about the effect of temperature on the reproduction of bacteria.

c) Describe how you could carry out an investigation to test your hypothesis.

d) How could the results of your investigation be applied to a real-world example of the use or control of bacterial reproduction?

Thinking Critically and Creatively 21. The offspring below has a male and a

female parent. Do all living things have two biological parents? Explain.

22. Explain why sexual reproduction is an advantage for species that live in a changing environment.

23. Science has manipulated reproductive processes for different organisms. Do you think manipulating these reproductive processes has resulted in positive or negative outcomes? Use your understanding of science to support your opinions.

Understanding Big Ideas Making New Connections

Applying Your Understanding 24. In eukaryotic cells, every time DNA is

copied a section of DNA at the end of each chromosome is lost. These sections are called telomeres.

a) At what point in the life cycle of a cell is the DNA copied?

b) How would the size of telomeres in cells that go through many cell divisions compare with telomeres in cells that rarely divide? Discuss the cell cycle as part of your answer.

25. Flowering plants that grow from seeds can contain both male and female reproductive structures within the flower, as shown in the diagram on the next page.

a) Where are the male and female gametes in a flower?

b) How are gametes in humans and flowers similar?

c) For fertilization, pollen must first land on the stigma of a plant of the same species. Some plants can pollinate themselves. For most plants, pollen from another plant is used. Why do you think pollen is often seen collecting on objects outside at certain times of the year?

d) What type of reproduction is described in this question? Explain your answer.

e) Compare this form of plant reproduction with what you know about human reproduction. How are they the same? How are they different?

78 MhE • Unit 1

Sample Material

anther where pollen is produced and stored

pollencases that containmale gametes

male reproductive structures

female reproductive structures

stigmasticky “lip” of the carpel that captures pollen grains

ovulessacs that contain female gametes

Thinking Critically and Creatively 26. Many fruit crops rely on bees to pollinate

the flowers on the trees. Bees are attracted to the flowers, which provide a nutrient called nectar. As they move from flower to flower searching for nectar, the bees carry pollen from one flower to another. Many people are now concerned about the decline in bee populations.

a) How do you think human actions could affect the bee populations?

b) Reflect on the following quote: “Every third bite of food you take, thank a bee or other pollinator.”

Why do you think the decline in bee populations is a problem?

27. Different mammals, such as cattle, sheep, dogs, and cats, have been cloned. This means a new offspring was developed using one parent’s body cell and its genetic information.

a) Based on your understanding of the term clone, why is this process called cloning?

b) What does this tell you about the offspring’s genetic information?

c) Is cloning considered asexual or sexual reproduction? Explain your answer.

Connecting to Self and Society 28. The liver is capable of regenerating. Even

if only 25% of the liver remains, it is capable of restoring itself back to full size.

a) Do you think mitosis or meiosis is involved in this process? Explain your choice.

b) Is this process considered reproduction? Why or why not?

c) Many scientists are working on ways to generate new organs and tissues in the laboratory. Do you consider this a valid research project? Support your opinion with scientifically informed reasons.

29. Refer to “First Peoples Perspectives in Science” on page xxii near the start of the textbook.

a) Review and reflect on the four themes of interconnectedness, transformation, renewal, and connections with place.

b) In a journal or in small groups, share ideas about how the concepts you have been learning about in this unit relate to these four themes.

Unit 1 review • MhE 79

Sample Material

Unit AssessmentUN

DERSTAND

K N O WD O

Dutch artist Vincent van Gogh (1853–1890) is almost as famous for the mysterious loss of his ear as he is for his paintings. Fast-forward over 100 years to Diemut Strebe, an artist interested in the interplay of art and science. Strebe worked with scientists to recreate van Gogh’s missing ear using cells donated by one of his modern relatives. The “living” ear is currently on display in a machine that mimics the conditions of the human body. This

sensational story is just one application of cloning. Cloning is the process of making an identical copy of a biological entity—a strand of DNA, a cell, an organ such as van Gogh’s ear, or even an entire organism.

How do we depend on reproductive cloning technologies?

Work as part of a group to do the following.

STEP 1 Reflect on the three options, their photos, and the question asked for each option.

STEP 2 Brainstorm three more options and questions of your own about a situation that involves cloning and reproduction.

STEP 3 Decide on one of the six option questions to investigate.

STEP 4 Plan and conduct a scientific inquiry to explore your question.

STEP 5 Organize and analyze the data and information that you find and collect.

STEP 6 Communicate the results of your inquiry in a suitable manner.

OptiOn A

Food ProductionAre you eating food that comes from cloned plants or animals?

80 MHE • Unit 1

Sample Material

Assessment CriteriaDid I and my group...

• Develop one or more questions that provided opportunities for rich investigation? QP

• Develop effective methods to collect and record reliable data and information? PC

• Apply different ways of knowing to analyze, reflect on, and draw meaningful conclusions that are consistent with evidence? PA

• Consider and demonstrate an awareness of assumptions, bias, and social, ethical, and environmental implications over the whole process of our inquiry? E

• Propose alternative courses of thought and/or action that contribute to care for self, others, community, and world? AI

• Construct evidence-based arguments using language, conventions, and representations appropriate for a specific purpose and audience? C

OptiOn B

Saving SpeciesShould we use cloning to help endangered species or bring extinct ones back to life?

Vancouver Island marmot

OptiOn C

Transplant TechnologiesWhat are the costs and benefits of creating human organs from donor cells?

Unit Assessment • MHE 81

Sample Material