Natural Selection And Genetic Variation Flashcards
What was the book Darwin published to make other scientists aware of his ideas
The origin of species
What did Darwin notice on the Galapagos Islands, and what was this theory called
There was variation in members of the same species and that those with characteristics that were more suited to their environment were more likely to survive. This was called natural selection
What did Wallace observe which provided evidence for evolution
Warning colours on species which deter predators from eating them
Describe antibiotic resistance in bacteria (6)
- Some bacteria in the population are resistant to antibiotics
- Antibiotics are introduced to the population
- Non-resistant bacteria die, the resistant bacteria survive. This is natural selection.
- The resistant bacteria reproduce asexually, passing in the antibiotic resistance allele. Asexual reproduction occurs really quickly.
5.Eventually the full population is resistant to the antibiotic.
Describe the evidence for evolution from each of:
A) Ardi, 4.4 million years ago
B) Lucy, 3.2 million years ago
C) Leaky’s discovery of fossils 1.6 million years ago
A) Leg structure suggests she walked upright, hand bone structure suggests she did not use them to help walk, and feet structure suggests she climbed trees
B) Arched feet, more adapted to walking than climbing, arm and leg size between that of a human and a chimp, and leg bones suggested she walked upright more efficiently than Ardi
C) Homo erectus species, have short arms and long legs, much more human than an ape. Brain size was much bigger than Lucy, nearly the same of a modern day human, and leg and feet structure suggests he was even more adapted to walking upright than Lucy.
How do Stone tools provide evidence for evolution. Make reference to their structure, layers and carbon dating.
1.Simpler tools are likely to be older than more complex ones
2. Stratigraphy, studying rock layers. Older rock layers are below younger one’s, so stone tools with deeper layers are usually older
3. Stone tools often have carbon containing materials in them, like wooden handles. Carbon 14 dating can be used to date this material to its environment. This is done by identifying the elements around the rock.
Studying rock layer ages to provide evidence for evolution is called…
Stratigraphy
Describe how the anatomy (structure) of the pentadactyl limb provides scientists with evidence for evolution
In many species, the pentadactyl limb has a very similar structure, like in mammals and reptiles. The similarity in the bone structure provides us with evidence that all these creatures have evolved from one common ancestor.
What is a pentadactyl limb
A limb with 5 digits
How has genetic analysis led to the suggestion of the three domains rather than the five kingdoms classification method.
Using RNA sequencing, scientists found that some members of the prokaryote kingdom are not as closely related as we thought.
Name the 3 domains
Archaea, Bacteria and Eukarya
Explain selective breeding and relate its use on corn.
Humans pick out plants/animals with specific traits and breed them to keep desired characteristics in the population. Corn plants with larger cobs would be selectively bred to make corn with large cobs consistently.
Describe a disadvantage of selective breeding on animals.
All will be bred for one desired characteristic, however all could have no resistance against a certain bacteria. If that bacteria were to be introduced into the population, the whole population would wipe out.
Describe genetic engineering
A process which involves modifying the genome of an organism to introduce desirable characteristics.
Describe the main stages of genetic engineering
including the use of:
A) restriction enzymes
B) ligase
C) sticky ends
D) vectors
A)Identify the gene you want, cut that section of DNA off and isolate it, done via restriction enzymes. Also, use the same restriction enzyme to cut open the vector DNA (A virus or bacterial plasmid)
B)The cut open vector DNA and gene are left with sticky ends
C)The sticky ends are mixed together with ligase enzymes. The ligase joins the pieces of DNA together to form recombinant DNA.
D)The recombinant DNA is inserted into other cells (like bacteria) and can now be used to provide the desired characteristic.
