Variation Flashcards
What is a species?
it a group of organisms that are capable of interbreeding to produce fertilities offspring
What is variation?
there are differences between members of the same species
What are the two types of variation?
- acquired variation
- inherited variation
What is acquired variation?
variations that are not inherited but learn
What is inherited variation?
variations that are controlled by genes
Give an example of acquired variation
knowing how to ride a bike
Give an example of inherited variation
having freckles
What are the two causes of inherited variation?
sexual reproduction
mutation
What are the 3 reasons that sexual reproduction causes genetic variation?
- independent assortment of chromosome at gametes formation during meiosis
- random fertilisation of an egg and sperm ensure no two offspring are the same
- during meiosis a process called crossing over occurs. this allows genes to be exchanged between chromosomes
What is the crossing over process?
during meiosis it allows genes to be exchanged between chromosomes
When does crossing over occur?
meiosis
What is mutation?
a spontaneous change in the number or structure of DNA cause by mutagens
What happens to mutations in a gamete?
they are passed on to the next generation
What happens to mutations in somatic (body) cells?
they are not passed onto the next generation
What may mutations produce?
new alleles, beneficial phenotypes, benign and maligned tumours, genetic defects in offsprings
What is the significance of inherited variation in evolution?
mutation is a major method by which new genetic information enters a species. it produces new genotypes and allows natural selection to pick the favourable genotypes and better adapted population evolves
What is a mutagen?
an agent that causes mutations
Give 3 examples a mutagens
- radiation (X-rays )
- chemicals(cigarette smoke)
- viruses
What are the two types of mutation?
gene (point) mutation
chromosome mutation
What is gene(or point) mutation?
it is a change in a single gene
What is chromosome mutation?
it is the change in number or structure of one or more chromosomes
Name and explain an example of gene mutation
sickle cell anaemia
Name and explain an example of chromosome mutation
Down syndrome
What is classification?
placing objects/organisms in groups based on similar characteristics
What is taxonomy?
the study of classifying organisms
What are the benefits of classification?
- to simplify the study of organisms
- to allow scientists to communicate with each other
