variation and evolution + classification and heredity Flashcards
define variation
varation within a species means that successful inbreeding organisms produce individuals with different characteristics
give two types of variation
inherited variation and aquired variation
define inherited variation
a characteristic that is controlled by genes e.g eye colour /hair colour
define aquired variation
a characteristic that is learned through life e.g piercings
define heredity
the passing on of features to offspring by means of genes
what is a gene
a section of DNA that causes the production of a protein- they are units of inheritance
what is gene expression
the way in which genetic information in a gene is decoded and used to make a protein
what is a somatic cell
refers to every cell in the body apart from egg and sperm cells
what is a mutation
a change in the amount of structure of DNA . can be extremely harmful if the mutation occurs in a gamete.
what are mutagens
agents that cause mutations, for example ionizing radiation or chemicals such as alcohol
what is a spontaneous mutation
wrong base sequence due to faulty DNA replication
what is a gene mutation
occur in a single gene, can be passed to offspring e.g cystic fibrosis
what is a chromosome mutation
large changes in the structure or number of one or more chromosomes e.g down syndrome is caused by 3 number 21 chromosomes
define evolution
the way in whch living things change genetically to produce new forms of life over a long period of time
what two scientists worked on evolution
darwin and wallace
