Topic 7 Key Words

Question 1

Diploid

Answer 1

Cells in which the nucleus contains two sets of chromosomes

Question 2

Gene

Answer 2

A section of DNA on a chromosome coding for one or more polypeptide

Question 3

Allele

Answer 3

An alternative form of a gene

Question 4

Genotype

Answer 4

All of the alleles that an organism carries on its chromosomes

Question 5

Pheonotype

Answer 5

Observable characteristics of an organism which are the result of the genotype and environmental factors

Question 6

Dominant allele

Answer 6

An allele that is always expressed in the phenotype of an organism

Question 7

Recessive allele

Answer 7

The characteristic is only expressed in the presence of another identical allele

Question 8

Codominant allele

Answer 8

Both alleles for one gene in a heterozygous organism contribute to the phenotype

Question 9

Homozygous

Answer 9

The allele of a gene are identical

Question 10

Heterozygous

Answer 10

The alleles of a gene are different

Question 11

Locus

Answer 11

The position of a gene on a chromosome

Question 12

Monohybrid inhertiance

Answer 12

Inheritance of a characteristic controlled by a single gene

Question 13

Dihybrid inheritance

Answer 13

Inheritance of two characteristics that are controlled by separate genes

Question 14

Epistasis

Answer 14

An interaction between genes when the expression of one gene suppresses the expression of another gene

Question 15

Autosome

Answer 15

All the non-sex chromosomes

Question 16

Homologous pair

Answer 16

Diploid organisms have pairs of chromosomes

Question 17

Sex-linkage

Answer 17

The expression of alleles located on sex chromosomes depends on the sex of the individual

Question 18

Species

Answer 18

Organisms that can reproduce to produce fertile offspring

Question 19

Population

Answer 19

All the organism of a species in one place at one time

Question 20

Gene pool

Answer 20

All the alleles present in a population

Question 21

Allele frequency

Answer 21

How common an allele is in the population

Question 22

Evolution

Answer 22

A change in allele frequency over time

Question 23

Differential reproductive success

Answer 23

Organisms with a phenotype better adapted to their environment have selective advantage and are not likely to survive and reproduce

Question 24

Community

Answer 24

All the organisms of all the species in one place at one time

Question 25

Speciation

Answer 25

The process of forming new species

Question 26

The Hardy-Weinberg Principle

Answer 26

A model that predicts the frequency of alleles, genotype and phenotype in a population

Question 27

Intraspecific variation

Answer 27

Individual of the same species have the same genes but different alleles - variation in their phenotype

Question 28

Interspecific variation

Answer 28

Individuals of different species have different genes and live in different environments - variation in their phenotype

Question 29

Continuous variation

Answer 29

Variation is smooth and continuous

Question 30

Discontinuous variation

Answer 30

Individuals fall into discrete groups with no intermediates

Question 31

Predation

Answer 31

When an organism (the predator) kills and eats another organism (the prey)

Question 32

Genetic drift

Answer 32

A change in allele frequency between generations due to random chance

Question 33

Directional selection

Answer 33

Individuals with an extreme type of characteristic are more likely to survive and reproduce

Question 34

Stabilising selection

Answer 34

Individuals with extreme types of characteristics are less likely to survive and reproduce

Question 35

Abundance

Answer 35

The number of individuals of a single in an ecosystem/ habitat and population size

Question 36

Distribution

Answer 36

Where a species is found in an ecosystem/ habitat

Question 37

Limiting factor

Answer 37

The thing that limits the maximum population size

Question 38

Carrying capacity

Answer 38

The maximum stable population an ecosystem can support

Question 39

Biotic factors

Answer 39

Ecological factors that make up part of the living environment

Question 40

Abiotic

Answer 40

An ecological factor that makes up part of the non-biological environment of an organism

Question 41

Niche

Answer 41

The role of species in an ecosystem

Question 42

Succession

Answer 42

A series of changes in species composition in a given place over time

Question 43

Climax community

Answer 43

Final stage of succession, few species dominant, stable equilibrium of species

Question 44

Deflected succession

Answer 44

A community that remains stable only because human activity prevents natural succession from taking place

Question 45

Environment

Answer 45

All the factors in a habitat that affect an organism

Question 46

Biosphere

Answer 46

The region of the earth the encompasses all living organisms

Question 47

Interspecific competion

Answer 47

Competition between organisms of a different species

Question 48

Intraspecific competition

Answer 48

Competition between organisms of the same species

Question 49

Habitat

Answer 49

The place where organisms live

Question 50

Conservation

Answer 50

Managing succession and balancing the ethical and commercial interests

Question 51

Biodiversity

Answer 51

The range and variety of genes, species and habitats within a particular region

Question 52

Allopatric speciation

Answer 52

Process of forming new species due to geographical isolation

Question 53

Sympatric speciation

Answer 53

The process of forming new species without geographical isolation

Question 54

Disruptive selection

Answer 54

Both extremes of the phenotype are more likely to survive and reproduce than the mean phenotype

Question 55

Ecosystem

Answer 55

A system in which all organisms interact with biotic and abiotic factors