Variation and Evolution Flashcards
Ch 17
Definition of variation?
Differences between two individuals.
Benefit of classification?
to simplify the study of organism.
Definition of classification?
Means placing objects into groups based on similar characteristics.
Whats taxonomy?
the science of classifying organisms.
Definition of species?
Group of organisms that can reproduce together to produce fertile offspring.
2 causes of variation within a species?
- mutation
- sexual reproduction
Acquired vs inherited variations?
Acq: not inherited, developed or learned during life.
inh: controlled by genes.
What are acquired variations?
not inherited, developed or learned during life.
What are inherited variations?
controlled by genes.
Give eg of acquired variations.
ability to walk, speak a language.
Give eg of inherited variations.
blood groups, eye colour, hair colour, attached/detached ear lobes.
Cause of inherited variations?
arise as a result of sexual reproduction and mutations.
How does meiosis give rise to variations?
rearranges genetic material.
produces non-identical cells
Whats a mutation?
is a change in the amount or structure of DNA.
What are mutagens?
agents that cause mutations.
A mutagen that causes cancer is called?
carcinogen
Name 4 main categories of mutagens.
1) ionizing radiation such as x-rays and ultraviolet radiation.
2) chemicals like formaldehyde.
3) some viruses.
4) smoking cigarettes: chemicals, radiation.
A gene (or point) mutation is?
a change in a single gene.
Name 2 types of mutation.
gene mutations,
chromosome mutations.
Examples of gene mutations?
sickle-cell anaemia,
haemophilia
Whats a chromosome mutation?
a large change in the structure or number of one or more chromosomes.
Eg of chromosome mutation?
down syndrome
Down syndrome is caused by?
one extra chromosome
