GSEB Class 7 Science Solutions Chapter 12 Reproduction in Plants

Question 1. Fill in the blanks:
(a) Production of new individuals from the vegetative part of the parent is called _________.
(b) A flower may have either male or female reproductive parts. Such a flower is called ___________.
(c) The transfer of pollen grains from the anther to the stigma of the same or of another flower of the same kind is known as ___________.
(d) The fusion of male and female gametes is termed as ___________.
(e) Seed dispersal takes place by means of and __________.
Answer:
(a) vegetative reproduction
(b) unisexual flower
(c) pollination
(d) fertilization
(e) wind, water, birds
In simple words: New plants growing from parts like stems or leaves is called vegetative reproduction. A flower with only male or female parts is called unisexual. Pollination is when pollen moves to the stigma. When male and female cells join, it's called fertilization. Seeds spread with the help of wind, water, and birds.

Exam Tip: Remember the basic definitions for each reproduction process and how nature helps spread seeds and pollen.

Question 2. Describe the different methods of asexual reproduction. Give examples.
Answer: Different methods of asexual reproduction are:
(a) Binary Fission: This action happens in single-celled organisms. The parent cell stretches and then splits into two identical daughter cells. Each daughter cell then grows into a separate adult.
(b) Endospore Formation: In this approach, a spore wall develops around a bacterial cell to make an endospore. This endospore then sprouts to create an active bacterium when conditions are good.
(c) Fragmentation: During this process, the body of the organism breaks into two pieces. Each piece then grows into a new filament, forming two organisms from just one original.
(d) Spore Formation: Spores are tiny, spherical, single-celled structures that have a thick wall for protection. These spores are kept inside a tough outer covering, which we call a sporangium. When conditions are favorable, the hard cover breaks, and the spores spread to start new growth.
(e) Budding: In yeast, new organisms are made by small bud formations that grow from the parent organism. After growing to full size, these buds detach and become new independent individuals.
(f) Vegetative propagation: When non-reproductive parts of a plant, such as stems, leaves, and roots, produce new plants, this is known as vegetative propagation.
In simple words: Asexual reproduction has different ways: Binary fission is when one cell splits into two. Endospore formation is when bacteria form tough spores to survive. Fragmentation is when an organism breaks into pieces, and each piece grows into a new one. Spore formation uses small, protected spores that spread and grow. Budding is when small growths on an organism break off and grow into new ones. Vegetative propagation is when plants grow new plants from their leaves, stems, or roots.

Exam Tip: Clearly define each method of asexual reproduction and provide a relevant example for each to score well.

Question 3. Explain what you understand by sexual reproduction
Answer: Sexual reproduction involves two parents taking part in the process of creating offspring. It is primarily found in higher plants where the male and female gametes combine to make a zygote. These zygotes grow into new individuals that are not identical to either parent. Offspring get traits from both parents. In sexual reproduction, both parent organisms continue to live after the reproduction process.
In simple words: Sexual reproduction means two parents create new life. Their special cells, called gametes, join together to make a baby plant. The new plant will have some features from both parents, but it won't be exactly like either one. Both parent plants usually survive this process.

Exam Tip: Highlight the involvement of two parents and the fusion of gametes as key characteristics of sexual reproduction.

Question 4. State the main difference between asexual and sexual reproduction.
Answer:
Asexual reproduction:
(a) Only one parent plant is involved.
(b) Occurs in unisexual plants.
(c) Occurs in lower plants.
(d) Reproductive organs are not present.
(e) In most methods, the original parent disappears.
(f) Processes like gamete formation or fertilization are not seen.
(g) Characteristics of only one parent are inherited.
(h) No need for seeds.
Sexual reproduction:
(a) Both male and female parents are involved.
(b) Occurs in bisexual plants.
(c) Occurs in higher plants.
(d) Fully developed reproductive parts are present.
(e) Original parents remain alive after the process of reproduction.
(f) Fertilization of gametes gives rise to zygote.
(g) Characteristics of both parents are inherited.
(h) Seeds are used to get new plants from a flower.
In simple words: Asexual reproduction needs only one parent, often happens in simpler plants, doesn't use special reproductive organs, and the parent often vanishes. Offspring get traits from just one parent, and seeds are not needed. Sexual reproduction needs two parents, happens in more complex plants, uses proper reproductive parts, and parents live on. Gametes join to make a zygote, and offspring get traits from both parents, usually involving seeds.

Exam Tip: For comparison questions, create two distinct lists or columns, making sure each point for one type of reproduction has a contrasting point for the other.

Question 5. Sketch the reproductive parts of a flower.
Answer: The reproductive parts of a flower include the male part, known as the stamen, and the female part, known as the pistil. The stamen consists of the anther and filament. The pistil includes the stigma, style, and ovary, which contains ovules.
(a) Stamen (Male reproductive part)
- Anther
- Filament
(b) Pistil (Female reproductive part)
- Stigma
- Style
- Ovule
- Ovary
In simple words: Draw a flower and label its boy and girl parts. The boy part is called the stamen, which has a little bag (anther) and a stick (filament). The girl part is called the pistil, which has a sticky top (stigma), a tube (style), and a round base (ovary) with tiny seeds inside.

Exam Tip: Practice drawing and labeling the stamen (anther and filament) and pistil (stigma, style, and ovary) accurately. Focus on their relative positions and shapes.

Question 6. Explain the difference between self-pollination and cross-pollination.
Answer:
Self-Pollination:
(a) Pollen grains are moved to the stigma of the same flower.
(b) Happens in bisexual plants that have an anther and stigma becoming mature at the same time.
(c) It takes place in plants like wheat, peas, etc.
Cross-Pollination:
(a) Pollen grains are carried to the stigma of a different flower.
(b) Happens in bisexual flowers where the anther and stigma mature at different times.
(c) It takes place in plants like lady-finger, tomato, brinjal, etc.
In simple words: Self-pollination is when a flower's own pollen lands on its stigma. This happens in flowers with both male and female parts that become ready at the same time, like wheat. Cross-pollination is when pollen from one flower goes to another flower's stigma. This occurs when male and female parts mature at different times, like in lady-finger plants.

Exam Tip: Clearly distinguish between pollen transfer within the same flower (self) and between different flowers (cross), noting the plant types and timing for each.

Question 7. How does the process of fertilization take place in flowers?
Answer: When a pollen grain lands on the stigma of a flower of the same species, it begins to grow a pollen tube from the stigma. This tube continues to grow inside the style until it reaches the ovule. Male cells are then released into the ovule for fertilization with the female egg cell, which forms the zygote. After this fertilization process, the ovary develops into a fruit, and the ovules become seeds.
In simple words: When pollen lands on a flower's sticky part (stigma), it grows a tube down to the ovule. Male cells travel through this tube to meet the female egg cell, creating a zygote. After this joining (fertilization), the flower's bottom part (ovary) turns into a fruit, and the tiny seeds inside grow into actual seeds.

Exam Tip: Detail the path of the pollen tube from the stigma through the style to the ovule, and clearly state the formation of the zygote and subsequent fruit and seed development.

Question 8. Describe the various ways by which seeds are dispersed.
Answer: Following are the ways by which the seeds are dispersed:

• Some light seeds, such as those of madar, which are hairy, dry, and small, are carried away by the wind to different locations.
• Spiny seeds and fruits, like those of Xanthium and Urena, stick to the clothes of people passing by and animals. These seeds are carried by these agents to various places.
• In some plants that have heavy seeds, like the coconut, water helps them move around as dispersing agents.
• Some seeds are spread when their fruits burst open, as seen with balsam and castor plants.

Exam Tip: Categorize seed dispersal methods by agent (wind, water, animals, bursting fruits) and provide at least one clear example for each.

Question 9. Match items in Column I with those in Column II:

Exam Tip: Carefully read both columns and recall the specific reproductive methods or plant features associated with each organism.

Question 10. Tick (e) the correct answer:
(a) The reproductive part of a plant is the
(i) leaf
(ii) stem
(iii) root
(iv) flower
Answer: (iv) flower
In simple words: The flower is the specific part of a plant responsible for making new seeds and fruits, helping the plant reproduce.

Exam Tip: Remember that while some plants reproduce vegetatively from leaves, stems, or roots, the primary reproductive organ involved in sexual reproduction for most flowering plants is the flower.

Question 10.
(b) The process of fusion of the male and the female gametes are called
(i) fertilisation
(ii) pollination
(iii) reproduction
(iv) seed formation
Answer: (i) fertilisation
In simple words: When the male and female reproductive cells (gametes) join together, this important process is called fertilization.

Exam Tip: Distinguish between pollination (transfer of pollen) and fertilization (fusion of gametes), as they are distinct but related processes.

Question 10.
(c) Mature ovary forms the
(i) seed
(ii) stamen
(iii) pistil
(iv) fruit
Answer: (iv) fruit
In simple words: After a flower is fertilized, its ovary grows and changes into a fruit. The tiny ovules inside the ovary become seeds.

Exam Tip: Connect the development of the ovary to fruit formation and ovules to seeds after successful fertilization.

Question 10.
(d) A spore-producing plant is
(i) rose
(ii) bread mould
(iii) potato
(iv) ginger
Answer: (ii) bread mould
In simple words: Bread mould is a type of fungus that creates tiny spores to reproduce and spread.

Exam Tip: Recall common examples of organisms that reproduce through spores, such as fungi and ferns.

Question 10.
(e) Bryophyllum can reproduce by its
(i) stem
(ii) leaves
(iii) roots
(iv) flower
Answer: (ii) leaves
In simple words: Bryophyllum is a unique plant that can grow new plants from the edges of its leaves.

Exam Tip: Remember Bryophyllum as a classic example of vegetative propagation through leaves, where plantlets grow from leaf margins.

Question 1. Make your own cactus garden by collecting pieces cut from different kinds of cacti. Grow the variety in one single flat container or in separate pots.
Answer: Students should make the cactus garden themselves, following the instructions given.
In simple words: This is a hands-on task for students to create their own cactus garden using cut pieces of different cacti.

Exam Tip: For practical activities, understand the scientific principles behind them (e.g., vegetative propagation in cacti).

Question 2. Visit a fruit market and collect as many local fruits as possible. If many fruits are not available, you can collect tomatoes and cucumbers (these are fruits, though we use them as vegetables). Make drawings of the different fruits. Split the fruits and examine the seeds within. Look for any special characteristics in the fruits and their seeds. You can visit a library also to learn about this.
Answer: Students should collect the fruits and study the characteristics of fruits and seeds themselves as per the activity.
In simple words: Students need to gather different fruits (including tomatoes and cucumbers), draw them, cut them open to see the seeds, and note anything special about the fruits or seeds. They can also use a library to learn more.

Exam Tip: When doing observation tasks, pay close attention to details like seed arrangement, fruit structure, and any features that aid dispersal.

Question 3. Think of ten different fruit-bearing plants. Remember that many vegetables are also fruits of the plants. Discuss with your teacher, parents, farmers, fruit growers and agricultural experts (if available nearby) and find out the manner of their dispersal. Present your data in the form of a table as shown below:
Answer:

Exam Tip: When preparing tables for data, ensure all columns are clearly labeled and the information provided is accurate and concise for each entry.

Question 4. Suppose there is one member of a particular kind of organism in a culture dish, which doubles itself in one hour through asexual reproduction. Work out the number of members of that kind of organism which will be present in the culture dish after ten hours. Such a colony of individuals arising from one parent is called a “clone”.
Answer: The number of organisms becomes twice the initial count in one hour through asexual reproduction. The number of organisms in:
1 hour = 1 x 2 = 2
2 hours = 2 x 2 = 4
3 hours = 4 x 2 = 8
4 hours = 8 x 2 = 16
5 hours = 16 x 2 = 32
6 hours = 32 x 2 = 64
7 hours = 64 x 2 = 128
8 hours = 128 x 2 = 256
9 hours = 256 x 2 = 512
10 hours = 512 x 2 = 1024
In simple words: If an organism doubles every hour, start with one, then multiply by two for each hour that passes. After ten hours, you'll have 1024 organisms. This group of identical organisms from one parent is called a clone.

Exam Tip: For problems involving exponential growth, clearly show each step of the calculation, demonstrating the doubling effect for each time interval.