Topic 4 Using Spec Flashcards
What did Charles Darwin believe
His theory of natural selection proposed that all species have evolved from simple life forms that first appeared on earth more than 3 billion years ago
What is genetic variation
Different individual animals in a population have different combinations of genes which show genetic variation
How does genetic variation link to survival of the fittest
Individuals that are best adapted to the environment due to their genes will have a greater chance of survival
How does survival of the fittest link to successful breeding
The individuals with the best chance of survival are most likely to successfully breed and pass these beneficial adaptations to the offspring
What were some problems with Darwin’s theory
Some scientists regarded the evidence as inconclusive
Challenged common belief that god created the natural world
At time genes weren’t discovered so Darwin was unable to suggest a method for the passing of characteristics between generations
What year did Wallace and Darwin produce writings
1858
What does antibiotic resistance in bacteria do and for evolution
Is a source of evidence for evolution
Causes bacteria to reproduce rapidly
If a mutated bacterium is resistant to antibiotics, it will survive exposure to antibiotics and go on to reproduce.
What is an example of an antibiotic resistance bacteria
MRSA
How does the pentadactyl limbs provide scientist with evidence for evolution
Helps compare similar structures in similar animals to prove that these organisms have evolved from the same organism
5 fingers
Many vertebrates
What kind of animals have pentadactyl limbs
Animals with backbones ( vertebrates)
How can fossils be used as evidence for human evolution
Fossils can be dated so scientists have evidence for what organisms looked like at different periods of time. Comparing fossils indicates how humans have changed over time
What is an ardi
Oldest fossilised human that remains are of ardi
From the species ardipithecus ramidus
4.4 million years ago
What was the Lucy fossil
From the species Australopithecus afarensis
3.2 million years old
Her bones suggested that she walked in an upright position like a human
Feet bones suggest she had feet similar to modern humans
Who is Leakey
archaeologist (fossil-hunter)
more recent discoveries of human fossils
1.6 million years ago
How have stone tools developed
Very basic tools found dating back to 2.6 mill years ago - mainly flakes of rock with a sharp edge
Around 1.6 mill years ago tools became more sophisticated and abundant
How can we tell when the stone tool was in use
Determine how deeply the artefact was buried. The deeper the object was stored, the older the object.
Compare the design to other stone tools that are already dated.
What does carbon dating do
Tells us when the rock was originally formed
What is the 3 domain system and who created it
Carl Woese proposed the 3 domain system. This classifies organisms based on chemical analysis.
What are the 3 domains
Archaea
Bacteria
Eukaryota
What is archaea
Primitive bacteria, many of which are extremophiles
What is eukaryota
Organisms that possess complex sub cellular structures
Why is selective breeding done on food crops
Causes disease resistance in food crops which is a useful characteristics as it improves yield
Why are animals used in selective breeding
animals that produce more milk or meat are also useful for yield-related reasons.
What is the process of tissue culture
Tissue sample taken from a plant
Then the cells are sterilised
Sample treated with hormones to trigger cell division and grown on an agar plate
ball of cells called a callus, forms and more hormones are added to cause roots and stems to grow.
plants can now be planted into soil.
Advantages of tissue culture in medical research
can use cell cultures to study cell processes and drug effectiveness
can also use them to study viruses that cannot survive outside of cells.
Advantages of tissue culture in plant breeding programs
can produce lots of genetically identical plants quickly from tissue culture cells.
can produce these plants any time of year in a lab
can increase the population numbers of rare plant species.
What is genetic engineering
Modifying an organisms genome by introducing a gene from another organism to produce a desired characteristic
How is vitamin A rice an example of genetic engineering
Lack of vitamin A can lead to blindness
Communities that lacked vitamin A used rice as the core of their diet
Therefore a gene that produced vitamin A was taken from bacteria and added to rice producing golden rice ( rich in vitamin A)
How is insulin producing gene an example of genetic engineering
gene that produces insulin can be inserted into bacteria. Those bacteria can then mass-produce insulin to treat people with diabetes.
Describe the stages of genetic engineering
Restriction enzymes (RE) cut a desired gene out of a chromosome RE cut a vector so now target gene and vector have exposed sections of single stranded dna known as sticky ends Enzyme called ligase used to join up sticky ends of gene and vector so now vector carries target gene. Marker gene added into vector to make it east to check that vector has taken up the target gene If the gene is delivered into cells by the vector before they have differentiated (at the egg or embryo stage), all cells in the developed organism will have the gene and show the characteristic.
