Evolution

Question 1

What is Independent Assortment?

Answer 1

When cells divide during meiosis, homologous chromosomes are randomly distributed to daughter cells. This causes Genetic variation.

Question 2

What is Crossing-Over?

Answer 2

Where there will be a random exchange of genes within a pair of homologous of chromosomes. This usually occurs during the metaphase. This causes Genetic variation.

Question 3

What are Somatic Mutations?

Answer 3

Some mutations are mutations that only affect the individual (eg. Mutations caused by UV exposure). These are called somatic mutations, as they only occur in somatic (body) cells.

Question 4

What are Germline Mutations?

Answer 4

Some mutations are heritable and can get passed onto the offspring (eg. Mutations causing cystic fibrosis). These are called germline mutations as they occur in the germline (sperm and egg) cells.

Question 5

What is Natural selection is?

Answer 5

Natural selection is the process by which an environmental factor (called a selective pressure) acts on a population, resulting in some organisms having a greater chance of survival than others.

Question 6

Give an example of natural selection:

Answer 6

If there are an equal number of dark-brown owls and light-brown mice. In areas where the ground is dark, owls would see light-brown mice easier and catch more light-brown mice than dark-brown mice. As a result, dark-brown mice would have an increased chance to survive and breed. With the next generation having more dark-brown mice due to them being ‘naturally selected’ by the owls. Hence, natural selection refers to the selection and passing of desirable traits due to environmental factors.

Question 7

What is Artificial Selection is…?

Answer 7

Artificial selection on the other hand, is the process in which breeders alter characteristics of animals to suit their own needs. For instance, domestic animals have been bred to have more desirable traits for humans rather than for their environment. Hence, artificial selection is the process by which we choose to breed particular organisms with desirable features.

Question 8

What is the difference between Natural Selection and Artificial Selection?

Answer 8

Natural selection is only done through environmental or selective pressures whilst artificial is caused by human factors.

Question 9

Explain why mice have evolved to have varying coat colours based on the concept of natural selection.

Answer 9

Dark-brown mice thrive on areas in which the ground is dark, resulting in them surviving and passing on their genes. However, in different areas with lighter surfaces, instead of dark-brown mice thriving, now light-brown mice would have a higher chance of survival. Resulting in a variety of coat colours dependent on the environment in which the mouse is located.

Question 10

The role of Darwin’s observation of the Finches on the Galapagos Islands and its impact on the development of the theory of evolution

Answer 10

Darwin’s observations on the Finches on the Galapagos islands resulted in the theory of sexual selection. Selective pressures or agents do not always act by killing. For instance, Darwin observed female birds often select brighter-coloured males for breeding. Resulting in those genes being passed on to the next generation. At the time, drawing thought of this was completely different from natural selection, as natural selection is something that kills. But now it is considered a part of natural selection as both change the species of a characteristic through selection.

Question 11

What is Sexual Selection?

Answer 11

Sexual Selection is when the selective pressures or factors that influence passing of genes are related to breeding. For instance, it is NOT environmental or artificial factors, but a bird may be more inclined to breed with a bright coloured bird passing that gene.

Question 12

Why can an organism’s phenotype lead to a species survival?

Answer 12

An organism’s phenotype can lead to a species survival. According to Darwin and Wallace, organism’s phenotype are well suited to their environment. Showing that a well suited phenotype for an environment will survive and pass on, changing the species as a whole and increasing their chance of survival in their specific selective pressures.

Question 13

Define speciation.

Answer 13

Speciation refers to the process by which one species splits into two or more separate species. It is responsible for the formation of any new species that appear in the fossil record.

Question 14

What is the second phase of speciation?

Answer 14

Step 2 Isolation:
Isolation refers to the prevention of gene flow throughout an entire population, stopping any difference in one population to another. For instance, island A has mutated genes whilst Island B has normal genes, making Island A more SIMILAR to a DIFFERENT SPECIES. That is why the whole species does not change but rather it branches off. This can happen because of geographical barriers.

Question 15

What is the first phase of speciation?

Answer 15

Step 1 Variation:
There must be variation within a population. This is because natural selection is involved in speciation and selection can only act on variation that is already present in the population.

Question 16

What is the third phase of speciation?

Answer 16

Step 3 Selection:
Once the previous steps are complete, natural selection affects the genotype of each group, converting the whole population in that area to change into a different species. This can lead to changes that prevent groups from breeding with each other even if they come back together in the future. Some changes include: Courtship behaviour, breeding seasons, sterility and chemical barriers.

Question 17

Draw a diagram of speciation

Answer 17

Visit Notes

Question 18

What is a mutation?

Answer 18

An alteration in DNA a particular section of DNA, altering the function of one or more genes or even entire chromosomes

Question 19

What is the term used to refer to the cause of mutations

Answer 19

Mutagens

Question 20

Look at the types of mutations on Google Classroom Slides

Question 21

Define Evolution

Answer 21

Evolution is the process by which populations of organisms change over generations.

Question 22

Define Genetic Variations

Answer 22

Due to meiosis, sexual reproduction results in nearly infinite possibilities of genetic variation, which is vital to the survival of species. In other words, sexual reproduction results in offspring that are genetically unique.

Question 23

Define Adaptation:

Answer 23

The evolutionary process whereby an organism becomes better able to live in its habitat or habitats.

Question 24

Define Evolution:

Answer 24

Changes in the heritable traits of a population of organisms as successive generations replace one another.

Question 25

Define Fitness:

Answer 25

An organism’s ability to pass its genetic material to its offspring / refers to an organism’s ability to survive, reproduce, and pass on its genes to the next generation.

Question 26

Define Genotype:

Answer 26

The genetic makeup of an organism

Question 27

Define Mutation:

Answer 27

Any change in the DNA sequence of a cell, or even the order of genetic data in chromosomes.

Question 28

Define Natural Selection:

Answer 28

The process through which populations of living organisms adapt and change. Where weaker animals die whilst stronger ones survive.

Question 29

Define Selective pressure:

Answer 29

Any reason for organisms with certain phenotypes to have either a survival benefit or disadvantage.

Question 30

Define Phenotype:

Answer 30

The observable physical properties of an organism

Question 31

Define Biological diversity or biodiversity:

Answer 31

refers to all the variety of life that exists on Earth.

Question 32

Define Species:

Answer 32

A species is a group of similar individuals that breed to produce fertile offspring under natural conditions.

In simpler terms, it is the small unit of biological classification.

Question 33

Do species have variation?

Answer 33

Within any species, there is variation.

Question 34

What are the main types of mutagens?

Answer 34

Physical mutagens, Chemical mutagens, Biological mutagens

Question 35

What is a physical mutagen and provide an example:

Answer 35

Physical mutagens include electromagnetic radiation, such as gamma rays, X rays, and UV light, and particle radiation, such as fast and thermal neutrons, beta and alpha particles. These are factors that influence the body PHYSICALLY.

Question 36

What is a Chemical mutagen and provide an example:

Answer 36

Chemical mutagens are naturally occurring or synthetic chemicals that can cause mutations. An example includes reactive oxygen species, benzene, gum elastic and rubber products, sodium azide, aromatic amines, alkaloids, deaminating agents, and PAH

Question 37

What is a Biological mutagen and provide an example:

Answer 37

Biological mutagens consist of bacteria and viruses capable of producing mutations in DNA. For instance Human papillomavirus (HPV)

Question 38

Are all mutagens bad?

Answer 38

Mutagens vary in effect, some may be beneficial whilst others may be detrimental.

Question 40

Explain homologous structures:

Answer 40

Homologous structures are structures that are similar in related organisms, because they have been inherited from a common ancestor.

Question 41

Explain analogous structures:

Answer 41

In contrast, analogous structures are also similar to each other (generally in terms of function, rather than appearance), but have developed independently of an ancestral connection.

Question 42

What is the similarity? between homologous and analogous structures.

Answer 42

Both structures are similar to each other in terms of function.

Question 44

Define what is meant by geographical distribution

Answer 44

Geographical distribution refers to the pattern of where species are found across different geographic regions.

Question 45

How does geographical distribution support the theory of evolution?

Answer 45

It supports the theory of evolution by showing that species in different regions often share common ancestors and have adapted to their specific environments over time. This distribution of related species across different locations provides evidence of evolutionary processes and how species change and diversify in response to their surroundings.

Question 45

How are mutations caused?

Answer 45

Through mutagens

Question 46

Explain what embryology is

Answer 46

Embryology is the study of embryo development.

Question 47

How can embryology help support the theory of evolution?

Answer 47

Embryology supports the theory of evolution by revealing similarities in the early stages of development among different species. Common ancestry is often reflected in these shared embryonic features, suggesting that species have evolved from a common ancestor. These similarities provide evidence for the evolutionary relationships between organisms and highlight the concept of descent with modification, a central idea in the theory of evolution.

Question 47

What is an example of natural selection?

Answer 47

There are a number of dark-brown owls and light-brown mice. In areas where the ground is dark, owls would see light-brown mice easier and catch more light-brown mice than dark-brown mice. As a result, dark-brown mice would have an increased chance to survive and breed. With the next generation having more dark-brown mice due to them being ‘naturally selected’ by the owls.