20.1 Variation And Inheritance Flashcards
Genotype definition
Genetic make up of an organism
Phenotype definition
Observable characteristic of an organism
Dominant allele definition
Version of the gene that will always be expresses if present
Recessive allele definition
Version of a gene that will only be expressed if two copies are present
Homozygous definition
Two identical alleles for a characteristic
Heterozygous definition
Two different alleles for a characteristic
Carrier definition
A persons that has one copy of a recessive allele coding for a genetically inherited condition
Continuous variation definition
A characteristic that can take ant value within a range eg height
Discontinuous variation definition
A characteristic that can only result in certain discrete values eg blood type
What causes genetic variations
Variation Arises as a result of mutation - changes in genetic code which are random and constantly taking place
It is essential for the process of natural selection and evolution
What is chlorosis
A condition in plants
Due to the plants not receiving enough chlorophyll
The leaves look pale or yellow
The lack of chlorophyll reduced ability of photosynthesis
What environmental factors causes chlorosis
Each having a different effect on the physiology of the plant causing the same change in phenotype
- lack of light
- mineral deficiencies
- virus infections
What is an organisms body mass determined by
Combination of both genetic and environmental factors
How is genetic variation created
Created by the version of genes you inherit from your parents
Individual mixture of alleles an organism inherits influences the characteristic they will display
