Evolution by natural selection Flashcards
Who first proposed the theory of evolution by natural selection?
Charles Darwin
What is variation?
Differences between members of the same species
What is continuous variation?
Variation which can have any value, e.g. height, weight
What is discontinuous variation?
Variation which can only have certain values, e.g. eye colour, shoe size
What is a mutation?
A change in an organisms DNA
Briefly describe the theory of evolution by natural selection.
Within a population there is variation. If a characteristic arises which is beneficial, that individual will live longer and reproduce more. This means the trait is more likely to be passed onto offspring and the trait will become more common in the population.
How old is the fossil Ardi?
4.4 million years old
How old is the fossil Lucy?
3.2 million years old
Which is more human like, Ardi or Lucy?
Lucy
What did Leakey discover?
Human like fossils around 1.6 million years old
How have stone tools changed during human evolution?
They have become more sophisticated. The materials used to make them have changed
How can stone tools be dated from their environment?
By looking at how deep in the ground they were discovered. The deeper they are, the older they are. They can also be dated by examining any items found with them, or by looking a how sophisticated the tools are.
What does it mean if an bacteria is antibiotic resistant?
The bacteria cannot be killed using antibiotics
Briefly describe how bacteria become antibiotic resistant.
Within a population of bacteria, some are more resistant to antibiotics than others. A mutation may arise which causes a bacteria to be resistant. When antibiotics are taken, this kills the least resistant bacteria first. The resistant bacteria survive and are able to reproduce more, due to less competition from other bacteria. They pass the resistance gene onto their offspring.
How can an increase in antibiotic resistant bacteria be avoided?
By only prescribing antibiotics when necessary. Patients should complete a full course of antibiotics. Use of antibiotics in farming should be restricted.
