Evolution Questions

Question 1

Name the term now used for the process that Charles Darwin called ‘modification by decent’?

Answer 1

Evolution. Was later applied to his later on by other scientists.

Question 2

List threes ways of determining weather two species are the same?

Answer 2

• interbreed to produce fertile offspring under natural conditions. Only if they could produce fertile offspring.
• studying the DNA, looking at weather proteins are identical.

Question 3

Name the 3 main steps in the process of speciation and explain.

Answer 3

• variation: must occur because natural selection is involved.
• Isolation: where different species are isolated from interbreeding from some mechanism. Prevents the gene from flowing throughout population.
• selection: natural selection affects she genotype and causes changes that prevent groups from breeding.

Question 4

During the speciation process, step 3- selection states that species won’t breed once they have been isolated. Why is this?

Answer 4

• courtship behaviour: animals may have developed different breeding songs, displays and rituals.
• breeding seasons: animals may breed at different times.
• sterility: animals may breed but the off Spring are sterile (like mules)
• chemical barriers: sperm may be killed by the chemicals in the female.

Question 5

What is the theory or evolution?

Answer 5

It states that similar species must be closely related to each other. Any change in the heritable traits within a population across generations.

Question 6

Name the process proposed by Charles Darwin that explained how a species can change over many generations.

Answer 6

Natural selection: where an environmental factor acts on a population and results in some organisms having more offspring than others.

Question 7

What is a selective agent? Name 4.

Answer 7

The environmental fact that acts on the population causing more offspring from an organism.

• a biotic factor: predator, bacterial infection or competition
• physical factor: temperature, water, soil nutrients or fire.

Question 8

Why is variation necessary for natural selection to occur?

Answer 8

All members of the species would be the same and have the exact same chance to survive if a predictor was to come. None of the, would have the unique adaption to survive and make more.

Question 9

Explain what antibiotics are and how they lost their effectiveness.

Answer 9

Some bacterias cause infectious diseases. Alexandra Fleming found a way to kill them using the fungi chemicals. These were called antibiotics and became popular in the 20th century. Because of this many lost their effectiveness and the bacteria had become resistant to them. This is due to natural selection.

Question 10

How natural selection can result in resistance?

Answer 10

Due to natural selection antibiotics and pesticides can become resistant. This is because the mutations allow the cells to destroy the chemicals (antibiotics) and then these species survive. They them produce more off Spring and soon enough the next generations are able to withstand the treatment.

Question 11

How must natural selection begin?

Answer 11

Diversity- that is a range of different traits with in a population. That variation must directly impact individuals ability to survive.

Question 12

What is artificial Selection?

Answer 12

Imposed by humans onto other organisms. People apply selective pressure by choosing to modify particular traits to achieve a purpose. It involves will and intent to alter an organism.

Question 13

What is meant by fitness?

Answer 13

Fitness describes the ability of an individual to live successfully in its environment.
This could be referring to traits that help the organism survive in its habitat. Eg. Camouflage.

Question 14

List some changes shown by the horse over geological time.

Answer 14

Firstly the horse had four toes and now has a hoof. Due to difference in ground hardness.
Legs became longer, head become larger.

Question 15

List some examples of how artificial selection has changed some species.

Answer 15

Budgerigars have been artificially selected because these colours, sizes and traits were preferred. Eg. Blue colour was a mutation.
Dog breeds were created. Eg labradoodle.

Question 16

Explain how fossils can provide evidence for changes in structure of a species over geological time.

Answer 16

They show the progression of evolution. And show that animals are not they same as they were back then. Scientist can calculate the age of an organism and record this. When more organisms are recorded they can be compared and organisms of the same species can create a story of how they have evolved. Evolution can lead to changes in shape, size of their bones, function but maintained the same layout.

Question 17

Demonstrate that organisms whose appearances are very similar are not always closely related.

Answer 17

Although some animals may appear to be similar (horse and zebra) they are not always closely related. This is because they do share a common ancestor. These animals have adapted and evolved but not everything changes. Animals branch off their common ancestor but still remain similar in some ways.

Question 18

How do fossils support the theory of evolution?

Answer 18

They show the different types of animals that lived on earth and the different states they went through (transitional form)

Homologous structure provide enough evidence to support theory of evolution. These bone structures can be compared to other organisms and similarities can be found.

Question 19

Who was the first person to propose natural selection?

Answer 19

Charles Darwin.

Question 20

List the evidence that supports the theory of evolution.

Answer 20

Fossils how the similarities between non loving and living organisms. DNA testing to see if proteins are the same. The similarities in embryos. Embryos of many different organisms look very alike. This shows that they developed form a common ancestor and developed in similar ways, gradually evolving in different ways.

Question 21

Explain the important role of genetic isolation in genetics evolution.

Answer 21

Isolation prevents the flow of that gene through the population. Meaning this gene is isolated and interbreed in the species.

Question 22

What was Charles Darwin famous for?

Answer 22

Suggesting that natural selection was the mechanism of evolution.

Question 23

What is a homologous structure?

Answer 23

In related species, characteristics that have the same basic structure. But do not have the same function for all species. e.g. humans and whales have 5 digits at the end go their limbs, but we each use these structures differently.

Question 24

How does comparative anatomy provides evidence for evolution?

Answer 24

Provides evidence because fossil records can be compared to modern bone structures now. Similarities can be found and can prove that animals come from a common ancestor. It can be noted that many of these animals may have the same structure but the function is different.

Question 25

Compare natural selection and artificial selection.

Answer 25

Natural selection is where the environmental fact acts upon the population where as artificial selection is imposed by humans who have the goal to achieve desirable features from a particular species. Both result in a varied species as an outcome and have a factor that changes the traits of the next generation.

Question 26

Outline the process by which bacteria have become resistant to antibiotics.

Answer 26

Antibiotics were popular in the 20th century, so most bacterias came into contact with antibiotics. Some of the bacteria is resistant to the antibiotics either due to their cell chemistry from mutations (where the genes have had a mistake during replication). The resistant bacterias that survived produce new offspring and continue to produce new generations with the resistant trait.

Question 27

Explain how natural selection has impacted insects.

Answer 27

1. Some insects have a natural resistance to pesticides. 2. plants are sprayed. Only resistant insects survive. 3. Other insects move onto the area, these breed wiht the resistant ones to produce off strong that are resistant. 4. When plants are sprayed again, more resistant insects survive and continue to reproduce.

Question 28

Huntington's disease causes a stand deterioration in sufferers over many years and finally death. Why is the gene still present in the population?

Answer 28

The gene is passed on before it can be selected out.

Question 29

Biologists state that predators can be of benefit to their prey. They can change the characteristics of their prey species. In this way, predators could be of benefit by?

Answer 29

Removing the sick and the weak. This would mean that there are more or he species to have because if they were to eat all the healthy ones first, the weak/sick ones would die out too, leading the species towards extinction.

Question 30

Natural selection process.

Answer 30

1. Variation occurs. 2. Selective pressure id applied, which some organisms will be more suited to. 3. The advantaged species will reproduce more than the disadvantaged, so their will be more advantaged in the next generation. 4. The favourable traits are seen in the next generation as there are ore of them. 5. Disadvantaged species reduces because their are less to produce and are still declining from elective pressure.