Genetics Flashcards
What is natural selection/survival of the fittest?
There are many different variations of one species and the weaker ones die out and so only the fitter ones are left, the fitter ones pass on their genes to their offspring and so slowly the species gets stronger and stronger
How many pairs of chromosomes are there in every human cell?
23
Which is the male chromosome X or Y?
Y
What is cystic fibrosis?
Cystic fibrosis is a disease that causes people to produce extra mucus it is a genetic disorder that can make it hard to breath for diagnosed people
what type of chromosomes do women have?
women have xx chromosomes
name 4 environmental effects on humans?
- personality
- height
- weight
- accent
name 4 genetic effects on humans
- eye colour
- skin colour
- natural hair colour
- genetic disease
what is mitosis?
mitosis is when a cell separates into two genetically identical daughter cells
What happens when wildebeest migrate?
Every year thousands of wildebeest start on a migration walking for hundreds across southern Africa, some die of exhaustion some are killed by predators, this is good for the population of the wildebeest because only the fittest survive the long journey
What where Charles Darwin’s 4 observations?
1) All organisms produce more offspring than could possibly survive
2) But population numbers tend to remain fairly constant over long periods
3) Organisms in a species show wide variation due to different genes
4) Some of the variations are inherited and passed on to the next generation
What did he deduce from his observations?
1) Since most offspring don’t survive because they are eaten or get ill and die, there is a struggle for survival
2) The ones that survive will pass on their genes, these are the strongest and fittest
Why is mutation important in natural selection?
A mutant has a new feature with high survival value eg long eared rabbits
What is artificial selection?
Artificial selection is when farmers choose the characteristics they want in a plant or animal (eg very red tomatoes, fat pigs, cows that produce lots of milk). The farmer breeds by mixing specific male and female sex cells.
What is a karyotype?
A karyotype is a diagram showing a full set of chromosomes arranged in their pares
How can you tell if someone has a syndrome?
The karyotype shows an abnormal set of chromosomes