Topic 4 - Natural Selection And Genetic Modification Flashcards
Advantages and disadvantages of biological control
An advantage is that it has longer lasting effects than chemical pesticides and it is less harmful to wildlife. A disadvantage is that introducing new organisms can create problems, as they could then become the pests themselves.
Describe the main stages of genetic engineering.
First special enzymes called restriction enzymes are used to cut out the desired DNA. These same enzymes are used to cut open the vector DNA. A vector is just a thing that is used to transfer the DNA. We can use plasmids for this or a virus. The cutting process leaves both the desired gene and the vector with sticky ends. Ligase enzymes are used to join together the DNA to make what is called recombinant DNA. The recombinant DNA is then inserted into other cells to make the protein that you want. For instance, we may want bacteria to produce insulin for us.
How does Lucy from 3.2 million years ago prove human evolution? (4)
Lucy also has a mixture of human and ape features, but she was more human-like than Ardi.
- Had arched feet, more adapted to walking (no big ape toe)
- Her arms and legs was between what you would find in apes and humans.
- Her brain was slightly larger than Ardi’s but still similar to a chimp’s
- Her leg structures suggest that she walked upright more efficiently than Ardi
How does Ardi from 4.4 million years ago prove human evolution? (4)
She has features of those found in humans and apes.
- Her feet structures suggests that she climbed trees - she had an ape-like big toe to grasp branches.
- Had long arms and short legs (more like apes than human)
- Her brains size was similar to a chimpanzee’s
- Her leg structures implies that she walked upright, her hand structures also suggest she didn’t use her hands to walk like apes.
How does the Turkana boy from 1.6 million years ago prove human evolution? (4)
He has a mixture of human and ape features, but he was more human-like than Lucy.
- His short arms and long longs were much like a human
- His brain size was much larger than Lucy’s - similar to humans.
- His feet and leg structures suggests that he was better adapted to walking upright than Lucy.
What is tissue culture?
Tissue culture is the growth of tissues or cells separate from the organism.
How does the anatomy of the pentadactyl limb provides scientists with evidence for evolution?
The similarity in bone structure provides evidence that species with a pentadactyl limb have all evolved from a common ancestor. If they’d all evolved from different ancestors, it’d be highly unlikely that they’d share a similar bone structure.
Advantages and disadvantages of selective breeding
Greater yields can be produced
Removes unwanted traits such as disease
High quality
But..... Causes inbreeding problems (mental and physical problems) Diversity is lost Time-consuming
What is a fossil and how do they prove evolution?
A fossil is any trace of an animal or plant that lived a long time ago. By arranging fossil in chronological order, gradual changes can be observed. This shows how species have changed and developed over billions of years.
What is the advantage of tissue culture in medical research?
It means that you can carry out all kinds of investigations on tissues in isolation. It also means that you can look at the effects of a particular substance or environmental changes on the cells of a single tissue, without complications from other processes in the whole organisms.
How does Antibiotic Resistance provide evidence for evolution?
This is because it makes the bacteria better adapted to an environment in which antibiotics (a selection pressure) are present. As a result, antibiotic resistance becomes more common in the population over time.
Who is Alfred Wallace?
Wallace was the scientist who worked with Darwin on the theory. Although, Wallace also came up with Natural selection independently, they worked together to create a paper for this theory. Darwin was recognised more than Wallace due to him adding detailed explanations and evidence.
How could you date stone tools? (3)
- Looking at the structural features of the tool or fossil. For example, simpler tools are likely to be older than more complex tools.
- Using stratigraphy - the study of rock layers. Older rock layers are normally found below younger layers, so tools and fossils in deeper layers are usually older.
- Stone tools are often found with carbon-containing material, e.g. a wooden handle. Carbon-14 dating can be used this material.
Advantages and disadvantages of genetic engineering
Allows a faster growth rate
Creates an extended life
Greater yields can be made
But.......
Can make bacteria and pathogens more stronger and resistant.
Reduces diversity.
Can cause future health problems.What is genetic engineering?
This involves modifying an organism‘s genome (DNA) to introduce desirable characteristics. This involves the use of enzymes and vectors.
