Genetics and Variation Flashcards
Where do you find chromosomes?
In the nucleus of a cell.
What is a fossil?
The remains or impression of a prehistoric plant or animal embedded in rock and preserved in petrified form.
Describe the structure of a DNA molecule.
Double-stranded helix held together by complementary base pairs.
What is an allele?
Different forms of the same gene.
What is the percentage chance of a land dinosaur turning into a fossil? Why?
1%, because it is likely that any dinosaur on land will be either eaten by scavengers or decomposed by microorganisms after it dies. Organisms decompose more quickly when they are in contact with oxygen.
What is natural selection?
The process whereby organisms better adapted to their environment tend to survive and produce more offspring.
What is a gene?
A section of DNA that codes for a particular characteristic.
What vertebrate group has live births?
Mammals
What do genes control?
They control certain characteristics or traits of an organism.
What is a phenotype?
The outward or physical appearance of an organism.
What is the difference between environmental and inherited characteristics?
Inherited characteristics are passed down genetically from one generation to the next, while environmental characteristics are usually associated with a learned behaviour.
Where do you inherit your genes from?
Your parents.
How many chromosomes do humans have in each body cell?
46 chromosomes which come in pairs.
How many chromosomes are there in a human sex cell?
23 unpaired chromosomes.
What does extinct mean?
A species that is no longer existing.
What type of variation would height be classified as?
Continuous Variation.
What type of variation would eye colour be classified as?
Discrete Variation.
How did giraffes end up with long necks?
The long neck of a giraffe was caused by a mutation but it was better suited for their environment so it became more common. You rarely see any giraffes with shorter necks.
What does heredity mean?
The transmission of genetic characters from parents to offspring.
Why could it be bad news for an organism if its environment changes?
It won’t be suited for the environment so it will die quicker.
What is a vertebrate?
An animal with a backbone.
Is ‘Aa’ classified as homozygous or heretozygous? Why?
Heretozygous because ‘Aa’ is made up of two different alleles.
What does a species need to survive?
Water, shelter, food and breathable air.
Who discovered evolution?
Charles Darwin.
