variation and inheritance

Question 1

what is a species

Answer 1

A species is a group of organisms that can interbreed to produce fertile offspring.

Question 2

differences between species is know as

Answer 2

variation, there are two types

Question 3

what is discrete variation

Answer 3

characteristics controlled by a single gene show discrete variation

Question 4

what are some examples of discrete variation

Answer 4

eye colour, hair colour, blood group and earlobes

Question 5

what is continuous variation

Answer 5

characteristics controlled by more than one gene (polygenic inheritance) show continuous variation

Question 6

what are some examples of continuous variation

Answer 6

height, mass, handspan

Question 7

environmental factors

Answer 7

Not all characteristics are controlled just by genetics and many are affected by environmental factors. For example, a
person’s height is determined by the genes they have and the availability of nutrients when they are developing.

Question 8

what is inheritance

Answer 8

An organism’s characteristics are controlled by the genes it inherits from its parents.

Question 9

what is a gene

Answer 9

a gene is a section of dna that codes for a protein that controls a particular characteristic (eg. eye or hair colour)

Question 10

what happens when an individual receives two copies of the gene for each characteristic

Answer 10

one copy is inherited from the father and one copy is inherited from the mother. an individual has a unique combination of their parents genetics

Question 11

what is an allele

Answer 11

alternative versions of a gene that can produce different characteristics is called an allele

Question 12

what are dominant alleles

Answer 12

Some alleles are dominant. If an individual inherits a dominant allele, they will always show that characteristic. Dominant alleles are represented using a capital letter.

Question 13

what are recessive alleles

Answer 13

Some alleles are recessive. Recessive alleles only show if an individual inherits two copies of that allele. Otherwise they are masked by the dominant allele. Recessive alleles are represented using a lowercase letter.

Question 14

what is a genotype

Answer 14

the genotype of an organism is the genetics (alleles) for a characteristic, usually represented by letters

Question 15

what is a phenotype

Answer 15

the phenotype of an organism is the physical appearance of a characteristic

Question 16

what is the meaning of the word homozygous

Answer 16

If the two alleles of a particular gene are same, the individual is described as being homozygous for that characteristic.

Question 17

what is the meaning of the word heterozygous

Answer 17

If the two alleles of a particular gene are different, the individual is described as being heterozygous for that characteristic.

Question 18

what are family trees used for

Answer 18

Family trees are diagrams which show relationships between different members of a family. It can be used to track the
inheritance of a trait.

Question 19

what are punnett squares used for

Answer 19

The possible genotypes and phenotypes of the offspring can be determined using a Punnett square, a grid that shows
the possible combinations of alleles that can result at fertilisation.

Question 20

what is P, F1 and F2

Answer 20

parental generation, first generation and second generation