Topic Nine - Reproductive Strategies

Question 1

What is asexual reproduction?

Answer 1

Asexual reproduction is the ability of an organism to produce new offspring without the involvement of a mate.

Question 2

What is unique about the genetic makeup of offspring in asexual reproduction?

Answer 2

Offspring produced through asexual reproduction are genetically identical to the parent, essentially creating clones.

Question 3

How many organisms contribute genetic material in asexual reproduction?

Answer 3

in asexual reproduction, only one organism contributes genetic material.

Question 4

Name and describe one method of asexual reproduction used by prokaryotes.

Answer 4

Prokaryotes primarily use binary fission, which involves the replication of the circular DNA molecule, attachment of DNA molecules to the plasma membrane, cell elongation, and division into two cells.

Question 5

Provide an example of an organism that reproduces through budding.

Answer 5

Hydra and yeast are examples of organisms that reproduce through budding, where a new organism develops from a growth on the parent.

Question 6

What is fragmentation, and which organisms commonly reproduce using this method?

Answer 6

Fragmentation is when an organism breaks into smaller parts, with each fragment developing into a mature organism. This method is common in filamentous cyanobacteria, molds, plants, and animals like sponges and sea stars.

Question 7

How do eukaryotes like Amoeba and Paramecium undergo asexual reproduction?

Answer 7

Eukaryotes like Amoeba and Paramecium reproduce asexually through simple cell division, which involves the process of mitosis.

Question 8

What is the significance of mitosis in eukaryotes?

Answer 8

Mitosis is essential for replacing old or damaged cells and for the growth of multicellular organisms from a single-cell stage to adulthood.

Question 9

What is vegetative propagation, and in which organisms does it occur?

Answer 9

Vegetative propagation is a form of asexual reproduction in plants. It is made possible due to the presence of undifferentiated cells in meristematic tissue and includes methods like runners, cuttings, rhizomes, tubers, bulbs, corms, and plantlets.

Question 10

What is parthenogenesis, and why is it referred to as a ‘virgin birth’?

Answer 10

Parthenogenesis is a form of asexual reproduction where offspring are produced from unfertilized eggs. It’s called a ‘virgin birth’ because it occurs without fertilization by sperm.

Question 11

In which organisms is parthenogenesis common?

Answer 11

Parthenogenesis is common in many invertebrate animals.

Question 12

What is obligate parthenogenesis?

Answer 12

Obligate parthenogenesis refers to populations of organisms that are all-female and exclusively reproduce through parthenogenesis, without the involvement of males.

Question 13

What are some biological advantages of asexual reproduction?

Answer 13

Biological advantages include rapid reproduction, efficient use of energy, and the ability to colonize new environments without the need to find a mate.

Question 14

Are there any biological disadvantages to asexual reproduction?

Answer 14

Yes, some disadvantages include limited genetic diversity, which can make populations vulnerable to diseases and environmental changes, and a lack of adaptability compared to sexually reproducing organisms.

Question 15

What are the advantages of asexual reproduction?

Answer 15

Asexual reproduction allows organisms to reproduce quickly.
It doesn’t require energy expenditure to find a mate.
Organisms are well-suited to their environment.
Rapid colonization of cleared areas is possible.
It does not rely on other organisms for reproduction.

Question 16

Why is asexual reproduction well-suited for rapidly colonizing cleared areas?

Answer 16

Asexual reproduction allows for the rapid production of offspring, which can quickly fill available spaces without the need for finding a mate or waiting for sexual reproduction.

Question 17

What is one of the major disadvantages of asexual reproduction?

Answer 17

One major disadvantage is the lack of genetic variation among offspring.

Question 18

How can a sudden change in environmental conditions affect a population relying on asexual reproduction?

Answer 18

If conditions change, the lack of genetic diversity in an asexually reproducing population can make the entire population vulnerable to extinction.

Question 19

What are the biological advantages of sexual reproduction with respect to genetic diversity in offspring?

Answer 19

Sexual reproduction introduces genetic diversity through the combination of genetic material from two parents.
Offspring inherit half of their genetic information from each parent, resulting in unique genetic combinations.

Question 20

How is sexual reproduction defined?

Answer 20

Sexual reproduction involves the fusion of gametes (eggs and sperms) produced by two separate parents. This process introduces genetic diversity into the offspring.

Question 21

Where are eggs and sperms produced in sexually reproducing organisms?

Answer 21

Eggs are produced in the ovaries by females, while sperms are produced in the testes by males.

Question 22

What is the process by which gametes are produced?

Answer 22

Gametes are produced via meiosis, a specialized form of cell division that halves the number of chromosomes.

Question 23

What is external fertilization?

Answer 23

External fertilization occurs when animals release their gametes into the external environment, and fertilization takes place outside the body of females.

Question 24

Which types of organisms typically engage in external fertilization?

Answer 24

External fertilization is common in aquatic invertebrates, bony fish, and amphibians.

Question 25

How does internal fertilization differ from external fertilization?

Answer 25

Internal fertilization involves males delivering sperm directly into the reproductive tract of females, and fertilization occurs inside the female's body.

Question 26

Which terrestrial animals use internal fertilization?

Answer 26

All terrestrial animals, except amphibians, use internal fertilization.

Question 27

How is genetic diversity achieved in sexual reproduction?

Answer 27

Genetic diversity results from the independent assortment of non-homologous chromosomes and crossing over between homologous chromosomes during meiosis.

Question 28

What proportion of genetic information is inherited from each parent in sexual reproduction?

Answer 28

Offspring receive half of their genetic information from each parent, contributing to genetic diversity.

Question 29

What are some key differences between asexual and sexual reproduction?

Answer 29

Key differences include the source of genetic variation (none in asexual, two parents in sexual), the speed of reproduction (faster in asexual), and the adaptability to changing environments (greater in sexual).

Question 30

Can you list some biological advantages of sexual reproduction?

Answer 30

Biological advantages include genetic diversity, adaptability to changing environments, and increased resistance to diseases and parasites

Question 31

What are some biological disadvantages of sexual reproduction?

Answer 31

Biological disadvantages include the energy cost of finding a mate, the risk of sexually transmitted infections, and the potential for producing fewer offspring compared to asexual reproduction.

Question 32

What is plant tissue culture, and how is it used in cloning?

Answer 32

Plant tissue culture is the process of growing clones of a plant from a small amount of tissue from one plant. It is used in cloning to produce genetically identical plants.

Question 33

What are the advantages of plant tissue culture?

Answer 33

Slow-growing plants can be produced in large numbers. Plants can be cultured year-round in controlled conditions. Virus-free tissue can be used to produce plants that do not carry the virus. Cultured plants can be transported internationally.

Question 34

What is embryo splitting, and how is it carried out?

Answer 34

Embryo splitting is a cloning technique where the cells of an early embryo are artificially separated into two cell masses, resulting in identical offspring. It is typically done through in vitro fertilization (IVF).

Question 35

Why are parents chosen for embryo splitting, and what is the goal?

Answer 35

Parents are chosen for desirable inherited characteristics, and the goal is to produce genetically identical offspring with these desired traits.

Question 36

What is Somatic Cell Nuclear Transfer (SCNT), and how does it work?

Answer 36

SCNT is a cloning technique where the nucleus from a somatic cell of an adult animal (donor nucleus) is transferred into an enucleated egg cell. The egg is then cultured until it begins embryonic development, and the resulting embryo is transferred into a surrogate animal's uterus.

Question 37

What is cloning, and how does it relate to SCNT?

Answer 37

Cloning is the process of creating genetically identical organisms. SCNT is one of the methods used for cloning, specifically in mammals, by transferring the nucleus from a somatic cell into an enucleated egg cell.

Question 38

What are the downsides or limitations of Somatic Cell Nuclear Transfer (SCNT)?

Answer 38

The success rate in initiating development of the egg cell after transferring the donor nucleus is low. For example, the kitten CC was only 1 of 87 embryos implanted into surrogate mothers, and Snuppy the puppy was the only survivor from 123 embryos implanted. Dolly the sheep was the only live birth from 277 cloned embryos, highlighting the low success rate.