Biology - Chapter 4 - Natural selection and genetic modification

What are antibiotics?

Drugs that can kill bacteria

How does antibiotic resistance occur?

A population of bacteria, one bacteria gets mutation in DNA causing it to be resistant, antibiotic is added and kills off all bacteria except the immune one, resistant bacteria continues to divide and eventually the entire colony of bacteria is resistant to that specific antibiotic

What is an example of a bacteria that is resistant to lots of antibiotics?

MRSA

What are fossils?

Preserved remains or traces of organisms that lived in the past

How do fossils provide evidence for evolution?

They show that species are similar to ones that are alive today

What are four ways fossils form?

Gradual replacement by minerals forming rock like substances, casts (a gap left after the decay of the organism), impressions (footprints) and preservation

What is extinction?

No individuals of that species remain

What are the reasons for extinction?

Environmental changes (eg temperature), new predators arriving, disease, competition between species and catastrophic events

What is the order of groups from kingdom to species?

Kingdom, phylum, class, order, family, genus, species

What did Carl Linnaeus do?

He created a new type of classification based off of characteristics and bone structure

Is ‘homo’ in Homosapiens the genus or the species?

The genus

Is ‘sapiens’ in Homosapiens the genus or species?

The species

What did Carl Woese do?

Created three domains based off of RNA sequencing: bacteria (prokaryote), archaea (dif type of prokaryote) and eukarya (eukaryote)

What are evolutionary trees?

They show the evolutionary relationships between different species of groups (common ancestors)

What is selective breeding?

When you take the best plants or animals and breed them together to get a better offspring with a desirable characteristic

How does selective breeding work?

Select the two with the desired characteristics and breed together. Then select the better offspring and breed together. Continue this over several generations and the gene pool will become much smaller

What is a gene pool?

A collection of different alleles in a population

What is a disadvantage of selective breeding?

It reduces the gene pool of a population

What did Darwin’s theory of evolution challenge?

the idea that God made all the animals and plants that live on the planet

How does Darwin’s theory link with survival of the fittest:?

Individuals with characteristics most suited to the environment are more likely to survive and breed successfully, these are then passed on to the next generation

What is the first step of genetic engineering?

Restriction enzymes are used to isolate the required gene, leaving it with sticky ends (short ends of unpaired genes)

What is the second step of genetic engineering?

A vector is cut using the same restriction enzyme, leaving it with corresponding sticky ends

What is the third step of genetic engineering?

The vector and isolated gene are joined by ligase enzyme

What is the fourth step of genetic engineering?

The vector inserts the gene into required cell

What is the last step of genetic engineering?

The genes are then transferred to the organism during early development which allows them to grow up to have the desired characteristics

What are the advantages of GMO?

Faster and more effective than selective breeding, improve yield and quality

What are the disadvantages of GMO?

Not ethical, potentially harmful to humans, toxins

Who is Ardi and what are her features?

A fossilised human skeleton that dates back 4.4 million years ago. She had long arms and long toes!! and was likely able to walk upright

Who is Lucy and what are her features?

Fossilised skeleton that dates back 3.2 million years ago. She was relatively small and had an ape like skull. She had similar feet to modern humans so suggests she walked upright

What does the pentadactyl limb suggest?

A common ancestor as many vertebrates have a very similar bone structure despite their limbs looking very different. For example birds and whales