B14 Evolution and Variation

Question 1

What is environmental variation?

Answer 1

Environmental variation refers to the differences in traits among individuals of the same species due to environmental factors rather than genetic differences. These factors can include:

Nutrition: Differences in food availability and quality.
Climate: Variations in temperature, rainfall, and sunlight.
Exposure to pollutants: Presence of toxins or pollutants in the environment.
Social interactions: Competition or cooperation with other individuals.

Question 2

How can environmental conditions affect genetically identical plants?

Answer 2

Different conditions like light and mineral ions can result in plants that do not look identical, with deprived plants being smaller and weaker.

Question 3

How can scientists investigate the effects of the environment on variety?

Answer 3

By using genetically identical plants or animals and placing them in different environmental conditions.

Question 4

What is genetic potential?

Answer 4

Genetic potential refers to the maximum capabilities an organism can develop under optimal environmental conditions, based on its genetic makeup.

Question 5

Variation may be?

Answer 5

Genetic or environmental

Question 6

What does darwin’s theory of eveolution state?

Answer 6

Darwin’s theory of evolution by natural selection basically states that life evolves through a process of descent with modification. Organisms with traits that better enable them to adapt to their environment tend to survive and reproduce in greater numbers, passing on these advantageous traits to future generations. This leads to gradual changes in populations over long periods. It states that all species of living things have evolved from simple life forms that first developed over 3 billion years ago.

Question 7

How do mutations contribute to evolution?

Answer 7

Variation: Mutations increase the genetic variation within a population. This variation is essential for natural selection to act upon.
Natural Selection: Some mutations can be beneficial, some harmful, and some neutral. Beneficial mutations can increase an organism’s chances of survival and reproduction. These organisms are more likely to pass on their genes, leading to an increase in the frequency of the beneficial allele in the population over time. This is natural selection.
Adaptation: Over generations, the accumulation of beneficial mutations can lead to adaptation, where populations become better suited to their environment.

Question 8

What is a mutation?

Answer 8

A mutation is a change in the DNA sequence that can lead to new phenotypes.

Question 9

What is speciation?

Answer 9

Speciation is the formation of new and distinct species in the course of evolution.

Question 10

What is the role of environmental change in evolution?

Answer 10

Environmental changes can create conditions where new phenotypes are advantageous, leading to rapid changes in a species.

Question 11

What is natural selection?

Answer 11

Natural selection is the process by which organisms better adapted to their environment tend to survive and produce more offspring.

Question 12

What is an example of speciation?

Answer 12

The divergence of Darwin’s finches in the Galápagos Islands, leading to different species adapted to various ecological niches.

Question 13

What is selective breeding?

Answer 13

Selective breeding, also known as artificial selection, is the process where humans intentionally breed plants or animals for particular traits. Breeders select individuals with desirable characteristics and use them to produce the next generation, gradually enhancing those traits over time.

Question 14

What are problems with selective breeding?

Answer 14

Reduced genetic diversity: This makes the population more vulnerable to diseases and environmental changes.
Inbreeding: Can increase the risk of genetic disorders due to the expression of recessive genes.
Health problems: Selecting for specific traits can unintentionally cause other health issues. For example, breeding dogs for certain physical characteristics can lead to breathing difficulties or joint problems.

Question 15

What are the principles of genetic engineering?

Answer 15

Isolate Target DNA
Extract the gene of interest (e.g., human insulin gene).

Cut DNA & Vector
Use restriction enzymes (e.g., EcoRI) to cut both the target DNA and a vector (e.g., plasmid).

Ligate DNA
Use DNA ligase to glue the target gene into the vector(plasmids/viruses).

Transform Host
Insert the recombinant vector into a host organism

Host organism now has desired phenotype

Question 16

What is genetic engineering?

Answer 16

Genetic engineering involves changing the genetic material of an organism by isolating and inserting specific genes into its genome.

Question 17

What are GM crops?

Answer 17

Genetically modified crops are plants that have had their genes altered through genetic engineering to exhibit desired traits.

Question 18

What are some benefits of GM crops?

Answer 18

Increased yields, resistance to pests and herbicides, improved nutritional value, and ability to withstand environmental stresses like flooding.

Question 19

What is the role of genetic engineering in human health?

Answer 19

Genetic engineering can help develop treatments for genetic disorders and improve the nutritional content of food crops.

Question 20

What are the ethical considerations of genetic engineering?

Answer 20

Ethical considerations include the potential for unintended environmental impacts, food safety concerns, and the moral implications of modifying organisms.

Question 21

What is tissue culture in plant cloning?

Answer 21

Tissue culture is a modern cloning method that uses plant hormones to grow thousands of new plants from a small piece of plant tissue. Plantlets are produced by stimulating callus cells with a different mixture of hormones and conditions to form tiny new plants.

It allows the production of thousands of identical plants with desired characteristics and helps preserve rare plant species.

Question 22

What is a callus?

Answer 22

A callus is a mass of identical plant cells formed from a small group of cells treated with plant hormones.

Question 23

What is embryo cloning in cattle?

Answer 23

Embryo cloning involves splitting early-stage embryos into multiple identical embryos, which are then transplanted into surrogate mothers.

It allows a high-quality cow to produce many more calves than through natural reproduction, improving breeding efficiency.

Question 24

What is adult cell cloning?

Answer 24

Adult cell cloning involves creating a new animal by inserting the nucleus of an adult cell into an empty egg cell and stimulating it to develop.

Question 25

What are the steps in adult cell cloning?

Answer 25

The nucleus is removed from an unfertilised egg cell. At the same time, the nucleus is taken from an adult body cell, for example, a skin cell of another individual of the same species. The nucleus from the adult cell is inserted in the empty egg cell. The new egg cell is given a tiny electric shock, which stimulates it to start dividing to form embryo cells. These contain the same genetic information as the original adult. When the embryo has developed into a ball of cells, it is inserted into the womb of an adult female to continue its development.

Question 26

What is the difference between embryo cloning and adult cell cloning?

Answer 26

Embryo cloning involves splitting early embryos, while adult cell cloning uses the nucleus of an adult cell to create a new organism.

Question 27

What are the ethical considerations of cloning?

Answer 27

Ethical considerations include animal welfare, the potential for misuse, and the implications of creating genetically identical organisms.

Question 28

What can tissue culture do?

Answer 28

Tissue culture can produce thousands of plants from a small tissue sample, ensuring genetic uniformity and scalability.

Question 29

Advantages of genetic engineering in Agriculture:

Answer 29

improved growth rates of plants and animals increased food value of crops, as genetically modified (GM) crops usually have much bigger yields than ordinary crops crops can be designed to grow well in dry, hot, or cold parts of the world crops can be engineered to produce plants that make their own pesticide or are resistant to the herbicides used to control weeds.

Question 30

How does mutation cause speciation?

Answer 30

Mutations introduce genetic variation within a population. If different populations accumulate different mutations and experience different selection pressures, they can diverge genetically over time. Eventually, these genetic differences can lead to reproductive isolation, meaning the populations can no longer interbreed and produce viable, fertile offspring. This reproductive isolation marks the formation of new species.

Question 31

What is golden rice?

Answer 31

Scientists have added a gene to wild rice that makes it produce beta carotene. This changes the colour of the wild rice to a golden colour. Beta carotene is needed by humans in order to make vitamin A - which is essential for good vision. The advantage of golden rice is that it can be used in areas where vitamin A deficiency is common, so it can help prevent blindness. In many countries golden rice is not being grown commercially over fears associated with genetically modified crops.

Question 32

Benefits of adult cell cloning?

Answer 32

Benefits: Therapeutic Cloning: SCNT can create patient-specific embryonic stem cells. These cells can then be differentiated into various cell types e.g.,nerve cells , heart cells to replace damaged tissues or organs without the risk of immune rejection. Reproductive Cloning: Cloning could allow infertile couples or individuals to have children who are genetically related to them. It could also enable the preservation of endangered species or the "revival" of extinct ones. Research: Cloned animals can serve as valuable models for studying human diseases and testing new therapies. They can also be used to produce pharmaceuticals and other valuable products. Agriculture: Cloning can be used to create genetically superior livestock with desirable traits, such as increased milk production or disease resistance.

Question 33

Risks of adult cell cloning?

Answer 33

Low Success Rate: SCNT is a technically challenging procedure with a low success rate. Many cloned embryos fail to develop properly, leading to miscarriages or birth defects. Health Problems in Cloned Animals: Cloned animals often exhibit health problems, such as premature aging, immune deficiencies, and organ abnormalities. These problems may be due to incomplete reprogramming of the donor cell nucleus. Ethical Concerns: Reproductive cloning raises ethical concerns about the potential for exploitation of women, the commodification of human life, and the psychological impact on cloned individuals. Technical Difficulties: The process of nuclear transfer and subsequent embryo development is complex and not fully understood. This can lead to unpredictable outcomes and potential risks to both the cloned organism and the surrogate mother. Genetic Diversity: Widespread cloning could reduce genetic diversity within populations, making them more vulnerable to diseases and environmental changes.

Question 34

Concerns about genetic engineering?

Answer 34

Ethical Concerns: Some people worry about "playing God" and altering the natural order. There are also concerns about the potential for misuse, such as creating "designer babies" or exacerbating social inequalities. Environmental Concerns: Genetically modified organisms GMOs could potentially harm ecosystems. For example, modified crops might outcompete native plants or lead to pesticide resistance in insects. Health Concerns: There are worries about the safety of consuming genetically modified foods and the potential for allergic reactions or other adverse health effects. While many regulatory bodies ensure safety, some people remain cautious.