Genetics and Evolution Flashcards
Which chemical are chromosomes and genes made from?
DNA
Put the following biological structures in size order starting with the largest: DNA, chromosome, nucleus, gene
nucleus → chromosome → gene → DNA
What are different versions of a gene called?
Alleles
Where are the chromosomes found?
In the nucleus of a cell
How many chromosomes does an ordinary human body cell contain?
46 / 23 pairs
How many alleles do we have for each characteristic?
Two, one from mum and one from dad
The allele for brown eyes (B) is dominant over the allele for blue eyes (b).
What colour eyes would these people have:
BB
Bb
bb
The people with BB and Bb would have brown eyes because a dominant allele is always shown in the characteristic even if only 1 copy is present.
The person with bb would have blue eyes because a recessive allele is only shown in the characteristic when 2 copies are present.
Which one of these people is heterozygous:
BB
Bb
bb
Bb because the 2 alleles at different.
Which of these people is homozygous:
BB
Bb
bb
BB and bb because the 2 alleles are the same.
What is a mutation?
A change in the DNA.
What controls our characteristics?
The genes we inherit from our parents.
The allele for brown eyes (B) is dominant over the allele for blue eyes (b).
A woman has blue eyes.
What are the woman’s alleles?
bb because the allele for blue eyes is recessive and a recessive allele is only shown in the characteristic when 2 copies are present.
Which scientist proposed the theory of evolution by natural selection?
Charles Darwin
What word describe the differences in characteristics between individuals of a species?
variation
Complete the sentences about the evolution of a bird species.
Choose from the following words: excretion, generation, mutation, reproduction, respiration, variation
The difference in beak length in the bird population is called ____________.
A change in a gene affects the beak length. Change in a gene is called ____________.
The birds with the longest beaks get more food. Getting more food improves a bird’s chances of survival and ____________.
The process of evolution take place over more than one ____________.
The difference in beak length in the bird population is called variation.
A change in a gene affects the beak length. Change in a gene is called mutation.
The birds with the longest beaks get more food. Getting more food improves a bird’s chances of survival and reproduction.
The process of evolution take places over more than one generation.
The allele for free ear lobes (E) is dominant over the allele for attached earlobes (e).
A mother is ee and a father is Ee.
What is the chance the child would have attached earlobes?
Their is 50% chance of the child having attached earlobes.
The picture shows a fish.
Give one characteristic that is caused by:
genes only
environment only
genes and environment
Genes: eye colour / pattern of scales / number of fins
Environment: scar
Both: length
