topic 4 - natural selection and genetic modification

Question 1

what was Charles Darwin theory of evolution?

Answer 1

New alleles arise through mutations
Selection pressures affect an organism strand of surviving and reproducing.
Those individuals with better characteristics and better adapted to the environment with the selection brushes have a better chance of survival so I’m more likely to breed successfully
This means the allelesthat are responsible for the useful characteristics are more likely to be passed on to the next generation

Question 2

how did the emergence of resistant organisms support Charles Darwin theory of evolution?

Answer 2

Bacterium with anti biotic resistant soil
Bacteria exposed to antibiotic
Resistant bacteria more likely to survive
Resistant bacteria reproduce and pass on resistant allele
Resistant allele becomes more popular in the population

Question 3

Arid fossil fuel

Answer 3

4.4 million years ago
Structure of feet suggested she climbed trees- ape like big toe to grasp branches
Long arms and short legs
Brain size was chimpanzee
Structure of hand bones suggests she didn’t use her hands to walk

Question 4

Lucy fossil fuel

Answer 4

3.2 million years old
Arched feet to help walking
Brain was slightly larger than Lucy’s

Question 5

Turkana boy

Answer 5

1.6 million years ago
Shirt arms and long legs were more human
Brain size larger close to humans

Question 6

What were development of stone tools overtime

Answer 6

2.5-1.5 million years ago
- Made simple stone tools called pebble tools by hitting rocks together to make sharp flakes. These could be used to scrape meat from bones or crack bones open.
2-0.3 million years ago
- sculpted rocks into shapes to produce more complex tools like simple and axis. These could be used to hunt, Dig,
chop and scrape the meat from bones
300,000-25000 years ago
- more complex stores. First evidence of flint and pointed tools and wooden spears
200,000 years ago- present
- flint tools widely used. Point tools including Arrowhead fish hooks and needles appeared around 50,000 years ago.

Question 7

How can stone tools be dated from the environment?

Answer 7

Looking at structural features
Using stratigraphy the study of rock layers
Carbon 14

Question 8

How has genetic analysis lead to the suggestion of three domain rather than the five kingdoms classification method?

Answer 8

People found some members of the prokaryote kingdom when as closely related as first thought. He proposed that this kingdom should be split into two groups called arches and bacteria and eukarya

Question 9

What is genetic engineering

Answer 9

as a process which involves
modifying the genome of an organism to introduce desirable
characteristics

Question 10

What is selective breeding and its impact on food and domesticated animals

Answer 10

is when humans artificially select the plants or animals that are going to breed so that the genes for particular characteristics remain in the population. Organisms are selectively bred to develop features that are useful or attractive.

Question 11

What is the process of selective breeding

Answer 11

From your existing stock select the ones which have the characteristics you’re affer.
Breed them with each other.
Select the best of the offspring, and breed them together.
Continue this process over several generations. Eventually, all the offspring will have the characteristic.

Question 12

What are the main stages in genetic engineering

Answer 12

The DNA you want to insert is cut out with a restriction enzyme. The vector DNA is then cut open using the same restriction enzyme.
The vector DNA and the DNA you’re inserting are left with sticky ends and are mixed together with ligase enzymes
These ligases join the pieces of DNA together to make recombinant DNA
The recombinant DNA is inserted into other cells
These cells can now use the gene you inserted to make the proteins you want

Question 13

What are strengths of using genetic engineering

Answer 13

in agriculture, crops can be genetically modified to be resistant to herbicides (chemicals that kill plants). Making crops herbicide-resistant means farmers can spray their crops to kill weeds, without affecting the crop itself. This can also increase crop yield.

In medicine, as well as genetically engineering bacteria to produce human insulin, researchers have managed to transfer human genes that produce useful proteins into sheep and cows. antibodies used in therapy for illnesses like arthritis, some types of cancer and multiple sclerosis.
These proteins can then be extracted from the animal, e.g. from their milk. Animals that have organs suitable for organ transplantation into humans might also be produced in the future.

Question 14

What are weaknesses of using genetic engineering

Answer 14

However, there are concerns about the genetic engineering of animals. It can be hard to predict what effect modifying its genome will have on the organism — many genetically modified embryos don’t survive and some genetically modified animals suffer from health problems later in life.

There are also concerns about growing genetically modified crops. One is that transplanted genes may get out into the environment. E.g. a herbicide resistance gene may be picked up by weeds, creating a new ‘superweed variety. Another concern is that genetically modified crops could adversely affect food chains — or even human health.

Question 15

What are advantages of using selective breeding

Answer 15

Genetic variation means some cattle will have better characteristics for producing meat than others. To improve me yields a farmer coukd select cows and balls with the characteristics that breed them together, getting the desired characteristics he wants

It led to the studies investigating alcoholism - it allowed researchers to find differences between the two types of rats including differences in their behaviour and the way their brains work

Question 16

What are disadvantages of selective breeding

Answer 16

reduces the gene pool — the number of affecent alleles (fors of a gene) in a population. This is because the “best” animals or plants are always used for breeding — and they are all closely related. This is known as inbresding.

Inbreeding can cause besith problems because there’s more chance of the organisms inheriting genetic defects when the gene pool is limited. Some dog breeds are susceptible to certain defects becaute of inbresding, e.g. beart disease in boxer dogs. This leads to ethical considerations - particularly if animals are deliberately bred to have negative charesteristios for medical research.

There can also be serious problems if a paw disease appears. There’s not much variation in the population, co there’s less shense of resistance alleles being present. All the stock are closely related to nuch other, to if one is going to be killed by a new disease, the others are also likely to succumb to i.