module 4 - 10.5 types of variation

Question 1

what are the 2 types of variation?

Answer 1

• interspecific variation
• intraspecific vartiantion

Question 2

what is interspecific variation?

Answer 2

differences between individuals of different species

Question 3

what is intraspecific variation?

Answer 3

differences between individuals of the same species

Question 4

what are the 2 causes of variation?

Answer 4

• genetic variation
• environmental variation

Question 5

what is genetic variation?

Answer 5

differences between individuals genetic material

Question 6

what is environmental variation?

Answer 6

differences between individuals environment

Question 7

what are the genetic causes of variation?

Answer 7

• mutations
• alleles
• meiosis
• sexual reproduction
• random fertilisation
• genetic drift

Question 8

what are mutations?

Answer 8

changes in the base sequence of the genetic material of an organism

Question 9

what are the 4 classes of mutations?

Answer 9

1. spontaneous mutations
2. mutations due to error-prone replication of DNA
3. errors introduced during DNA repair
4. induced mutations caused by mutagens

Question 10

what are mutagens?

Answer 10

things that produce mutated alleles

Question 11

what are alleles?

Answer 11

• different versions of a gene
• produced by mutations

Question 12

what are most of the mutations like in alleles?

Answer 12

• neutral
• no observable change in function of protein or RNA product

Question 13

what is a gene?

Answer 13

basic unit of heredity & is a sequence of nucleotides in DNA/RNA that encodes synthesis of RNA/polypeptide

Question 14

what is meiosis?

Answer 14

nuclear division to produce gametes

Question 15

how does meiosis generate genetic assortment?

Answer 15

• independent assortment
• crossing over

Question 16

what is independent assortment?

Answer 16

independent orientation homologous chromosome pairs along metaphase plate during metaphase 1 and orientation of sister chromatids in metaphase 2

Question 17

what is crossing over?

Answer 17

the physical exchange of homologous chromosomal regions by homologous recombination during prophase 1

Question 18

what is sexual reproduction?

Answer 18

reproduction by joining genetic material from 2 genetically different organisms

Question 19

what is random fertilisation?

Answer 19

the effect of chance as to which gametes fuse in fertilisation

Question 20

what is genetic drift?

Answer 20

change in frequency of an allele in a population due to random sampling of organisms that reproduce

Question 21

what does genetic drift cause?

Answer 21

• causes alleles to disappear completely and reduce genetic variation
• causes initially rare alleles to be more frequent/fixed

Question 22

what is asexual reproduction?

Answer 22

• doesn’t involve fusion of gametes or change in number of chromosomes
• offspring inherit full set of genes from single parent
• happens by mitosis

Question 23

how does genetic variation occur in asexual reproduction?

Answer 23

mutations

Question 24

how can prokaryotes increase genetic variation?

Answer 24

• conjugation
• transformation
• transduction

Question 25

what is conjugation?

Answer 25

DNA transfer by direct contact

Question 26

what is transformation?

Answer 26

• uptake of DNA from the environment

Question 27

what is transduction?

Answer 27

DNA transfer from a virus

Question 28

why are plants more affected by their environment?

Answer 28

because they are sessile

Question 29

what are 2 examples of pure environmental variation?

Answer 29

1. taraxacum officinal - dandelions show different leave form and size when grown in sunny/shaded locations
2. hydrangea macrophylla - flower colour depends on availability of aluminium ions in soil, which depends on soil pH