ESTAS 3

Question 1

mitosis

Answer 1

nuclear division giving rise to genetically identical cells

Question 2

meiosis

Answer 2

reduction division in which the chromosome number is halved from diploid to haploid resulting in genetically different cells

Question 3

genotype

Answer 3

the genetic make-up of an organism in terms of the alleles present

Question 4

phenotype

Answer 4

the observable features of an organism

Question 5

homozygous

Answer 5

having two identical alleles of a particular gene

Question 6

heterozygous

Answer 6

having two different alleles of a particular gene

Question 7

dominant

Answer 7

an allele that is expressed if it is present

Question 8

recessive

Answer 8

an allele that is only expressed when there is no dominant allele of the gene present

Question 9

sex-linked characteristic

Answer 9

a characteristic in which the gene responsible is located on a sex chromosome and that this makes it more common in one sex than in the other

Question 10

variation

Answer 10

differences between individuals of the same species

Question 11

mutation

Answer 11

genetic change (the way in which new alleles are formed)

Question 12

gene mutation

Answer 12

a change in the base sequence of DNA

Question 13

adaptive feature

Answer 13

an inherited feature that helps an organism to survive and reproduce in its environment

Question 14

fitness

Answer 14

the probability of an organism surviving and reproducing in the environment in which it is found

Question 15

process of adaptation

Answer 15

the process,
resulting from natural selection, by which
populations become more suited to their
environment over many generations

Question 16

food chain

Answer 16

chain showing the transfer of

energy from one organism to the next, beginning with a producer

Question 17

trophic level

Answer 17

the position of an
organism in a food chain, food web, pyramid of
numbers or pyramid of biomass

Question 18

food web

Answer 18

a network of interconnected

food chains

Question 19

producer

Answer 19

an organism that makes its own organic nutrients, usually using energy from sunlight, through photosynthesis

Question 20

consumer

Answer 20

an organism that gets its energy by feeding on other organisms

Question 21

herbivore

Answer 21

an animal that gets its energy by eating plants

Question 22

carnivore

Answer 22

an animal that gets its energy by eating other animals

Question 23

decomposer

Answer 23

an organism that gets its energy from dead or waste organic material

Question 24

population

Answer 24

a group of organisms of one species, living in the same area, at the same time

Question 25

community

Answer 25

all of the populations of different species in an ecosystem

Question 26

ecosystem

Answer 26

a unit containing the
community of organisms and their environment,
interacting together, e.g. a decomposing log, or a lake