topic 4 - natural selection and genetic modification Flashcards
how does the anatomy of the pentadactyl limb provide scientists with evidence for evolution?
have evolved from a common ancestor
they have similar bone structure but used for different functions
what evidence do we have for human evolution based on stone tools?
as they evolved, the complexity of the tools increased, indicating larger brain size
how can stone tools be dated back to their environment?
using stratigraphy - the study of rock layers
the further down the rocks are, the older they are
what was darwins theory of evolution?
natural selection and the theory of survival of the fittest
when was ardi around?
4.4 million years ago
when was lucy around?
3.2 million years ago
when was leakys discovery of fossils?
1.6 million years ago
what are the main stages of genetic engineering?
RESTRICTION ENZYMES - recognise specific sequences of DNA and cut out the DNA at these points (left with sticky ends at these points)
LIGASE - these enzymes are used to join 2 pieces of DNA together at their sticky ends
VECTORS - these can be used to insert DNA into other organisms
what are 2 types of vectors in genetic engineering?
plasmids and viruses
what is genetic engineering?
a process which involves modifying the genome of an organism to introduce desirable characteristics
what are the advantages of tissue culture on medical research?
can carry out medical experiments in isolation
can look at the effects of a particular substance / environmental change of a single tissue and not the whole organism
what are the advantages of tissue culture on plant breeding programmes?
whole plants can be grown
can be grown all year
produced as clones, genetically identical
what is the process of tissue culture?
taking little pieces of tissue and growing them so that scientists dont have to go through selective breeding
how does the emergence of resistant organisms support darwins theory of evolution?
bacteria sometimes develop random mutations and these alleles can change the characteristics of the bacteria and can be better suited to an environment
abiotic resistance becomes more common as they are better adapted
how did darwin and wallace’s ideas of evolution impact modern biology?
both first developed idea of evolution by natural selection and is still relevant in modern biology, that all life changes happen through evolution
