Variation And Evolution Flashcards
Define classification
Means placing objects into groups based on similar characteristics
Define taxonomy
Is the science of classifying organisms
What is a species
SPC is a group of similar organisms that are capable of naturally interbreeding with each other to produce fertile offspring
What is the benefit of classification
To simplify the study of organisms
What is variation within a Species
It means that in a group of successfully interbreeding Organisms the individual members share different characteristics
What are acquired variations
They are not inherited they are learned or developed during life
What are inherited variation is
There are controlled by jeans
What cause inherited variations
Sexual reproduction and mutations
What are the three reasons sexual reproduction causes genetic variation
Humans have 46 chromosomes this means there about 8 million different combinations of chromosomes available as a result of meiosis
During meiosis process called crossing ever takes place this allows jeans to be exchanged between chromosome allowing combination of these jeans from the mother and the father
I fertilisation owing the random assortment of chromosomes in the egg and the sperm a vast range of variation as possible
What is a mutation
Spontaneous change in the amount or structure of DNA
Why domutations produce no change in the characteristics of a diploid organism
Because the dominant allele on the second homologous chromosomes can still produce the original protein
What is the name for non-reproductive cells
Somatic
Why Are mutations not harmlful to somatic cells
Because the gene that was altered may not be active in the particular body part example skin cell suffers mutation for saliva production
Why are me mutations in gametes very serious
This mutation may be inherited by the zygote and passed on to all thousands cells in the developing child
What are beneficial mutations
They produce an even better protein than the original ones
What cause mutations
May arise naturally when DNA fails to produce exact copies of itself or fails to repair
What is the mutagen that causes cancer
Carcinogen
What are the categories of mutagens
Ionising radiation
Chemicals
Viruses
Types of mutation
And alter gene called allele cause
Cystic fibrosis
Cancers
Sickle cell anaemia
What is sickle-cell anaemia
Inherited blood disorder caused by A mutation in the haemoglobin Jean
What is a chroma zone mutation
Large change in the structure or number of one or more chromosomes
Example of a chromosome mutation
Down syndrome
What is evolution
The way in which living things change genetically to produce new forms of life over a long period of time
What is the theory of natural selection based on
Three observations and to conclusions
What are the three observations
Over breeding
Population numbers remain constant
Inherited variation is occurring populations
What are the two conclusions
There is a struggle for existence
Natural selection
What is natural selection
Process by which those organisms with genetically controlled characteristics allowed them to well adapt to their environment to survive and reproduce
What is Speciation
The production of new species as a result of evolution
What are evidence of evolution
Fossil study
Comparative anaotomy
