Unit 4 Summary 7

Question 1

DNA sequencing

Answer 1

DNA sequencing: The determination of the base (nucleotide) sequence of a gene. In one common method, the DNA is cleaved using a restriction enzyme, and the cleaved fragments are subjected to various reactions before being separated by gel electrophoresis. DNA sequencing can be used to determine relationships between individuals of a species, and for determining whole genomes of populations or species.

Question 2

DNA hybridisation

Answer 2

DNA hybridisation: Formation of a hybrid molecule when single-stranded DNA of two different organisms is brought together and their complementary bases bond together.

Question 3

Thermal stability

Answer 3

Thermal stability: (Of DNA) Temperature needed to dissociate half of the hybrid molecules formed after bonding the DNA of two different organisms (DNA hybridisation)

Question 4

Amino acid sequencing

Answer 4

Amino acid sequencing: Method of determining the order of amino acids in a protein

Question 5

Mitochondrial DNA

Answer 5

Mitochondrial DNA: Circular DNA molecule found in the mitochondria

Question 6

Molecular clock

Answer 6

Molecular clock: Estimated rate of nucleotide substitution (number of bases per year) for a particular region of DNA; used to estimate number of evolutionary changes.

Question 7

Phylogeny

Answer 7

Phylogeny: The evolutionary relationships of organisms, usually depicted by a branching tree

Question 8

Phylogenetic tree

Answer 8

Phylogenetic tree: A phylogenetic tree or evolutionary tree is a branching diagram or “tree” showing the inferred evolutionary relationships among various biological species or other entities—their phylogeny—based upon similarities and differences in their physical or genetic characteristics.

Question 9

Cladogram

Answer 9

Cladogram: a branching diagram showing the cladistic relationship between a number of species.
Cladistics: Method of building phylogenetic trees based on homologous features that indicate that organisms are related

Question 10

Speciation

Answer 10

Speciation: The evolution of a new species; for example, as a result of the splitting of an ancestral species by a geographic barrier and subsequent natural selection and/or genetic drift in the separated populations

Question 11

Allopatric speciation

Answer 11

Allopatric speciation: The physical isolation of populations that begins the process of speciation due to geographic isolation

Question 12

Geographical isolation

Answer 12

Geographical isolation: Populations of species that are isolated by geographic barriers or distance so that they cannot interbreed; begins the process of allopatric speciation

Question 13

Selective pressures:

Answer 13

Selective pressures: Limiting factors in the environment of an organism that affects its survival and reproduction

Question 14

Subspecies

Answer 14

Subspecies: Populations within a species that show genetic differences across a geographic range; also called races

Question 15

Reproductive isolation

Answer 15

Reproductive isolation: Organisms of different species are not able to interbreed due to behavioural, mechanical or geographic isolations.

Question 16

Species

Answer 16

Species: The fundamental unit of biological classification recognised by one or more unique characteristics; organisms of the same species (a gene pool) are generally reproductively isolated from other species (other gene pools)

Question 17

Divergent evoltion

Answer 17

Divergent evolution: The evolution of different species from a single ancestor species, especially as a result of reproductive isolation

Question 18

Homologous structures

Answer 18

Homologous structures: Similar features in organisms that have a common evolutionary origin, regardless of their function.

Question 19

Adaptive radiation

Answer 19

Adaptive radiation: Rapid divergence of an evolutionary lineage from a recent common ancestor

Question 20

Convergent evolution

Answer 20

Convergent evolution: The independent evolution of structures with similar form and function in unrelated organisms, resulting from the influence of similar environmental factors.

Question 21

Analogous structures

Answer 21

Analogous structures: Features (such as organs) in different species that serves the same functions

Question 22

Extinction

Answer 22

Extinction: In evolution, the dying out of a species or group of species

Question 23

Background extinction

Answer 23

Background extinction: Average rate of natural loss (extinction) over time

Question 24

Mass extinction

Answer 24

Mass extinction: Rapid loss of many species or groups of organisms due to an event, for example the end of the Cretaceous period with the death of dinosaurs and many animal groups