4.3 - Emerging Resistance Flashcards
What defines bacteria as resistant?
Bacteria are labelled resistant when they are not killed by antibiotics which previously were used as cures against them.
How do bacteria reproduce?
Bacteria reproduce at a fast rate.
What can mutations during reproduction lead to?
Mutations during reproduction can result in new genes, such as the gene for antibiotic resistance. This creates a new strain.
What effect does exposure to antibiotics have on bacteria?
Exposure to antibiotics creates a selection pressure, as those with antibiotic resistant genes survive and those without die.
What happens to bacteria with antibiotic resistance?
Those with antibiotic resistance can reproduce and pass on the advantageous gene to their offspring.
How does the presence of resistant bacteria relate to natural selection?
The presence of these new, resistant bacteria supports Darwin’s theory of natural selection, as the new bacteria have been selected by the environment to have a feature (resistance) advantageous to survival.
What is the consequence of increasing populations of antibiotic resistant bacteria?
This population of antibiotic resistant bacteria increases.
Why do bacterial diseases spread rapidly?
Bacterial diseases spread rapidly because people are not immune to these new resistant bacteria and there is no treatment for it.
What is MRSA?
MRSA is an example of a superbug that is resistant to many different types of antibiotics.
Where is MRSA commonly found?
MRSA is common in hospitals and spreads when doctors and nurses move to different patients.
What does fossil evidence show about the development of organisms?
Fossil evidence shows that developments in organisms arose slowly, as carbon dating and related techniques help estimate when a fossil was formed.
Who is Ardi and what is significant about her?
Ardi, or Ardipithecus ramidus, is the oldest known human ancestor, estimated to have lived 4.4 million years ago. Her fossilized skeleton contains humanoid features and resembles an ape, indicating she is phenotypically between the two.
The presence of this intermediate organism supports the idea that natural selection and evolution occurred gradually.
What does the bone structure in Ardi’s feet suggest?
The bone structure in Ardi’s feet is different from that of chimpanzees, suggesting that humans and chimpanzees evolved separately.
What is Lucy and what does her fossilized skeleton indicate?
Lucy is a fossilized skeleton dating from 3.2 million years ago. Her bone structure suggests she walked in an upright, human-like position, but she had a small, chimp-like skull and brain, representing another intermediate between apes and early humans.
What contributions did Louis and Mary Leakey make to the theory of natural selection?
Louis and Mary Leakey discovered fossils in the 1950s that supported the theory of natural selection, including an early fossil with remnants of stone tools and Homo habilis, an important early human species.
