Download Forms of Asexual Reproduction

Mr. Storie
10S Science
Reproduction – Asexual methods
Forms of Asexual Reproduction
In all the forms of asexual reproduction, there is just one parent. The unicellular organisms of the Protista
kingdom, such as the amoeba, reproduce asexually by standard mitosis. Members of the Monera kingdom,
such as bacteria, are single-celled organisms that do not contain a true nucleus. Bacteria reproduce asexually
by a process called binary fission.
Yeast cells are unicellular fungi that reproduce asexually by budding. In the budding of yeast, the parent
cell pushes out part of its wall forming a bulge or bud. Then the nucleus divides by mitosis. One of the two
new nuclei moves into the bud and the other one stays inside the parent cell. After a new wall forms between
the two nuclei, the daughter cell may remain attached to the parent, or it may break away and produce a new
yeast culture.
In binary fission, the parent cell divides equally into two daughter cells. In budding the parent cell divides
unequally. The daughter cell is smaller than the parent cell. But after budding is complete, the daughter
cell may grow to the size of the parent.
Organisms of the kingdom Fungi, such as the mould Penicillium and mushrooms, also reproduce by
sporulation. The formation of spores or sporulation is another form of asexual reproduction. In sporulation,
the parent organism produces a large number of spores. Each spore is a cell that was formed by mitosis and
contains the same number and kinds of chromosomes as the parent cell.
Moulds grow in thin web-like strands called hyphae. The hyphae grow over the surface of the food (bread)
and eat the food for energy. Sporangia form on the tips of the hyphae that have grown across the surface. In
each sporangium, hundreds of spores develop by mitosis.
Vegetative propagation is a kind of asexual reproduction that can take place in any of the growing parts of
plants. These parts may be roots, leaves, or stems, including the kinds of underground stems called tubers
and bulbs. A potato is an example of a tuber, and an onion is an example of a bulb.
The root of a carrot or turnip (the part we eat) placed in water will grow into a new plant. Strawberry plants
propagate themselves by stem-like structures called runners. A runner takes root and produces a new plant.
Many house plants, such as geraniums may be grown from stem cuttings placed in water. Bulbs of onions
and tulips grow into complete new plants. The tubers of potatoes and yams sprout new plants from their
eyes.
In the kingdom Animalia, animals are divided into two main groups – vertebrates and invertebrates.
Invertebrates, such as sponges, jellyfish, worms, shellfish and insects, make up about 97% of all animal
species. Most invertebrates can reproduce by asexually means. Some animals are able to replace or
regenerate a lost part. Lizards, starfish and planeria, can regenerate whole limbs. Lobsters can regenerate a
lost claw. One arm of a starfish can re-grow a whole new body. Examples like these are sometimes called
fragmentation, and are another example of asexual reproduction.
Mr. Storie
Reproduction – Asexual methods
10S Science
DIAGRAM STUDIES
A. On the line below each diagram, write the type of asexual reproduction that is shown. Choose from
the following: sporulation budding regeneration binary fission
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2.
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4.
B. One the line below each diagram, write the type of vegetative propagation that is shown. Choose
from the following: tuber bulb leaf runner stem
5.
6.
7.
8.
Mr. Storie
10S Science
Reproduction – Asexual methods
QUESTIONS
A. Decide whether each statement is true or false. Write T or F on the line before each statement. If the
statement is false, correct the underlined word or phrase.
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1. In vegetative propagation, the new plant has the same chromosomes as the parent plant.
2. A form of asexual reproduction in bread mold is binary fission.
3. Regeneration is a form of asexual reproduction in the starfish.
4. A lobster can grow a new claw by sporulation.
5. In budding, the nuclei of the parent cell and daughter cell are different.
6. The spores of a potato can sprout into a new plant.
7. A strawberry plant can reproduce by runners.
8. An amoeba has no true nucleus and reproduces by binary fission.
B. In each blank write the word that will make the sentence true. Use the words below:
Mitosis cutting bulbs root tubers equally unequally fungi
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2.
3.
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5.
6.
7.
8.
A group of organisms that can reproduce by spores are the ____________________.
In carrots, the organ of vegetative propagation is the ________.
The _________ of tulips and onions can grow into new plants.
In budding, the parent cell divides ___________________.
Geraniums may be reproduced from stem _______________.
In binary fission, the parent cell divides _________________.
Yams are a kind of underground stem called _______________.
A amoeba cell nucleus divides by ______________.
C. Write simple diagrams to show the steps of Mitosis.