SB4 Evolution Flashcards
SB4a
1) What is evolution?
What is the fossil evidence for the species that lived:
2) 4.4 million years ago
3) 3.2 million years ago
4) 1.6 million years ago
1) Evolution is a gradual change in the characteristics of a species over time.
2) Ardipithecus ramidus (Ardi)
Her leg bones show that she may have been able to walk upright. She had very long big toes which would have allowed her to climb trees.
3) Australopithecus afarensis (Lucy)
Leg bones suggest she walked upright.
Toes looked much like today’s human feet but they were much more curved.
4) Homo erectus
They were quite tall, and started using tools
SB4a
1) Explain how evidence from fossils supports current ideas about human evolution.
2) Describe how stone tools created by humanlike species have developed over time.
3) How is the data of a stone tool estimated from its environment?
1) The fossils show that the skull of the human increased, suggesting that their brain size increased, suggesting that they became smarter. Also, the height and shape of the fossils change over time, which shows how the characteristics of humans have changed.
2) Stone tools become more advanced and efficient over time, showing how humans have became smarter and were able to develop more efficient tools.
A stone tool would have been formed by hitting it with another rock to knock flakes off.
3) The sediment surrounding it is carbonated, and the stone tool is estimated to be approximately the same age as the rock surrounding it.
SB4e
1) Why are new breeds and varieties are created?
2) What is meant by a ‘genetically modified organism’?
1) New breeds and varieties are created for the following reasons:
- Disease resistance (how well they cope with diseases)
- Yield (how much useful product they make)
- Coping with certain environmental conditions
- Fast growth
- Flavour
Mnemonic: Delicious yogurt is crushed frozen fruit
2) A genetically modified organism is an organism that has had its DNA changed, in order to introduce desirable characteristics.
SB4e
1) How is selective breeding carried out?
2) What are the benefits and risks of selective breeding on domesticated plants and animals?
1) Selective breeding is carried out with these steps:
- Decide which characteristics are important enough to select.
- Choose parents that show these characteristics. They are bred together.
- Choose the best offspring with the desired charactersitics to produce the next generation.
- Repeat the process continuously over many generations, until all offspring show the desired characteristics.
2) Benefits of selective breeding:
- New varieties may be economically important, by producing more or better quality food
- Animals can be selected that cannot cause harm
Risks of selective breeding
- Reduced genetic variation can lead to attack by specific insects or disease
- Rare genetic disorders can be passed down
SB4f
1) What is tissue culture and what does it form?
2) Are tissue cultured cells similar or different to each other and why?
3) Which part of the plant is most useful for producing a tissue culture and why?
1) Tissue culture is the growing of cells or tissues in a liquid containing nutrients or on a solid medium. These may form a callus (a clump of undifferentiated cells), which are sometimes treated to form specialised cells.
2) Tissue culture produces many genetically identical cells which are clones. This is because small clippings are taken from one plant, so the plant that is grown will have the same DNA.
3) Shoot tips are the best for plant culture because they grow quickly.
SB4f
1) What are two advantages of using tissue culture in medical research?
2) What are the different advantages of tissue culture to grow clones of a single plant?
3) When is tissue culture used?
1) Using cell cultures, scientists can investigate how infected cells respond to new medicines without risking harm to animals and humans.
Cultures of human cells can be developed into tissues if cultured correctly.
2) Many plants can be grown very quickly, and you can create lines of plants with the same desirable characteristics. Also, plants can be grown all year round.
3) Tissue culture is used in commercial plant nurseries to grow plants to sell. Tissue culture is also used to produce new plants of very rare species which are at risk of extinction.
SB4g
1) What are the main stages of genetic engineering?
2) What are some uses of selectively bred organisms (in agriculture)?
3) What are some uses of genetically engineered organisms (in agriculture, in medicine)?
1) The main steps in the process of genetic engineering:
- Restriction enzymes are used to isolate (cut out) the required gene, this leaves sticky ends on the DNA.
- The same restriction enzymes are also used to cut the vector open, leaving it with corresponding sticky ends
- Any DNA molecule used to carry new DNA into another cell is called a vector.
- The vector is usually a bacterial plasmid (a piece of circular DNA found inside bacterial cells) or a virus
- The gene is joined to the plasmid using an enzyme called ligase
- The recombinant DNA plasmid is transferred to the cells of animals, plants or microorganisms at an early stage in their development so that they develop with desired characteristics
2) To produce crops or animals with a high yield.
To produce crops that are disease resistant.
3) In agriculture: Golden rice contains genes that makes it produce a chemical that is turned into vitamin A in the human body, which could be used in areas where Vitamin A deficiency is common and so can help prevent blindness.
In medicine: The gene for human insulin can be inserted into bacteria which then produce human insulin which can be collected and purified for medical use to treat people with diabetes.
SB4h
1) How can crop plants be modified to make them resistant to insect pests?
2) How can using GM organisms increase the amount of food we produce?
1) Crop plants can be modified by putting the genes of a bacterium, that control the production of a natural insecticide, into the plant so that all the cells in the plant produce the toxin.
2) GM organisms may produce natural insecticides, which means that they are less likely to be affected by an insect. This can improve crop yields.
SB4h
1) How can using GM organisms cause problems in the environment?
2) What are the advantages and disadvantages of using GM organisms?
1) GM crops could be harmful to humans, as toxins from the crops have been detected in some people’s blood.
Pollen produced by plants could be toxic, and harm insects that transfer it between plants.
2) Advantages include:
- Increasing the yield of the crop
- Increasing its resistance to insects
Disadvantages include:
- Could contain toxins that are harmful to humans
- New genes could transfer to other wild plants or insects through pollination
SB4i
1) What is biological control?
2) Why do we need to produce more food?
3) How can biological control help increase crop yield?
1) Biological control is using organisms to control pests.
2) We need to produce more food because the human population continues growing.
3) By releasing a natural predator into the crop growing area, the number of pests can be reduced. This means that the crops will be less likely to be affected by pests, and therefore will produce a larger yield.
SB4i
1) How can using biological control cause problems (in decreasing biodiversity)?
2) How can using fertilisers increase crop yield?
3) How can fertilisers damage the environment (by causing pollution)?
1) The reduction in the population of a certain species can affect the numbers of certain organisms in the food web.
2) Fertilisers contain mineral ions that plants absorb from the soil to make healthy new cells. Adding fertilisers to crops help them to grow well.
3) If not all the fertiliser is absorbed by a crop, some may get into nearby streams, rivers and lakes. This can cause pollution and lead to the death of organisms in the water.
SB4d
1) How are organisms classified into smaller and smaller groups (based on their characteristics)?
2) How does the binomial naming system work?
3) What are each of the five kingdoms?
1) Kingdom, phylum, class, order, family, genus, species
Use this mnemonic to remember: King Phillip Came Over For Good Soup.
2) The binomial system of naming species uses Latin words. Each name has two parts, the genus and the species. The genus is the first part of the name, and the species is the second part.
(For example, in the name Erithacus rubecula, Erithacus is the genus, and rubecula is the species.)
3) Animals, plants, fungi, prokaryotes, protists
SB4d
1) What is genetic analysis?
2) Why do biologists often now classify organisms into three domains?
3) What are the 3 domains and their description?
4) What kingdoms are under the eukarya?
1) Genetic analysis in examining and comparing the DNA sequences in different organisms.
2) Through genetic analysis, it was found that the DNA of Archaea is more similar to eukaryotes.
3) The three domains are:
- Archaea (cells with no nucleus, genes contain unused sections of DNA)
- Bacteria (cells with no nucleus, unused sections in genes)
- Eukarya (cells with a nucleus, unused sections in genes)
4) The kingdoms under eukarya are: animals, plants, fungi and protists.
SB4e
1) Why might a certain genetic disorder be more common in a selectively bred population?
2) Why would the emergence of an infectious disease be more of an issue for a selectively bred population?
1) Selective breeding reduces the gene pool for the population. A smaller gene pool means that it’s more likely that individuals will inherit harmful genetic disorder.
2) There’s less genetic variation in the new population, because they have been selectively bred. This means that there’s smaller chance of there being any alleles in the population that would give the organisms resistance to the disease. The organisms are closely related, so if one individual gets the disease, the others are also likely to get it as well.
SB4f
1) Why are animal tissue cultures are useful for testing the effects of drugs?
2) How could you produce a tissue culture of an animal organ or muscle for drug testing?
1) Using animal tissue culture allows scientists to investigate the effects of a drug on a single animal tissue, without the complications of a whole organism.
2) Extract a sample of cells from the animal organ/ muscle. Add enzymes to the sample of tissue to separate the cells from each other. Place the separate cells in a culture vessel containing a growth medium with all of the nutrients that they need to grow and divide. After several rounds of cell division, split cells into separate vessels to encourage further growth.
