Timaru Girls’ High School
Level 3 Biology
External
4 Credits
Keywords for AS 91605 –
Demonstrate understanding
of evolutionary processes
leading to speciation.
1.
Adaptive radiation
The evolution of a number of different species of plant or animal
from one ancestral species, eg. Darwin’s Galapagos finches.
2.
Allopatric speciation
Speciation occurring where organisms are initially capable of
actually interbreeding but cannot because they are
geographically separated.
3.
Allopatry
Describes groups of organisms that could potentially interbreed
but do not because they are geographically separated.
4.
Analogous structures
Structures that are superficially similar but have evolved in
different ways, eg. the wings of birds, bats and insects.
5.
Ancestral type
A hypothetical individual possessing the ancestral or primitive
characteristics of a group of species.
6.
Artificial selection
Deliberate selection by humans for desired features in a plant or
animal species.
7.
Autopolyploidy
A type of polyploidy where the multiple sets of chromosomes are
all derived from the same species.
8.
Cladistics
A method of classification in which animals and plants are placed
into groups called clades when they share characteristics that
are thought to indicate common ancestry.
9.
Classification
The arrangement of organisms into a series of groups based on
physiological, biochemical, and anatomical or other relationships.
10. Cline
A gradual variation in the characteristics of a species or
population over its geographical range.
11. Convergent evolution
The development of superficially similar structures in unrelated
organisms, usually because the organisms live in the same kind
of environment.
12. Divergent evolution
An accumulation of changes in the gene pools of two (or more)
populations, leading to the formation of races, sub-species,
species etc.
13. Evolution
The gradual process by which the present diversity of plants and
animals arose from the earliest and most primitive organisms.
14. Geological record
Fossils preserved in sedimentary rock layers that can be used to
trace the evolutionary history of a species.
15. Homologous
structures
Structures that have a similar evolutionary history but have
developed to suit different functions, eg. wings of a bat, flippers
of dolphins and arms of humans have all evolved from paired
pectoral fins of an ancestral fish.
16. Hybrid
The offspring of a mating where the parents differ in at least one
characteristic. The term is usually applied to offspring of widely
different parents, eg. different varieties/species.
17. Instant speciation
The formation of a new species through autopolyploidy or
allopolyploidy. Because the chromosome numbers of the new
‘instant’ species do not match that of the original species they
cannot interbreed.
18. Macro-evolution
The formation of a completely new species, genera, etc.
19. Micro-evolution
The accumulation of (through mutation) of new characteristics in
a species.
20. Natural selection
The process that brings about new species by eliminating
individuals that are less well adapted to their current environment
from a population showing variation, allowing mainly individuals
with advantageous adaptations to survive and reproduce.
21. Parallel evolution
The development of related organisms along similar evolutionary
paths due to strong selection pressures acting on all of them in
the same way.
22. Phyletic speciation or
Sequential speciation
Speciation where adaptation by a species to changing
environments creates a new species. This occurs because along
with adaptations to the environment, barriers to breeding with the
‘original’ species are developed.
23. Phylogeny
The evolutionary history of an organism or a group of related
organisms.
24. Polymorphism
The existence of three or more distinctly different forms within a
plant or animal species, eg. the different ‘castes’ found in social
insects such as bees or ants.
25. Primitive feature
A feature that is assumed to have been present in the
evolutionary ancestor of a species of group of species. It may or
may not have been simpler, depending on the evolutionary
history of the species.
26. Reproductive isolation
A barrier to breeding that exists due to differences in mating
season or mating organs, eg. flowers flowering at different times
of year.
27. Ring species
Two apparently distinct species that are connected by a series of
intermediate geographical and structural subspecies between
which interbreeding can occur.
28. Selection pressure
The extent to which organisms possessing a particular
characteristic are either eliminated or favoured by environmental
demands.
29. Speciation
The development of one or more species from an existing
species. It occurs when sympatric or allopatric populations
diverge so much from the parent population that interbreeding
cannot occur.
30. Species
A category used in the classification of organisms that consists of
a group of organisms that can usually breed together and
produce fertile offspring.
31. Sub-species
A group of individuals within a species that breed more freely
among themselves than with other members of the species and
resemble each other in more characteristics.
32. Sympatric speciation
Speciation occurring where organisms living within the same
area are theoretically capable of interbreeding, but cannot
because of difference in behaviour, flowering time etc.
33. Sympatry
Describes groups of organisms that live in the same
geographical area.
34. The new synthesis
Also referred to as ‘neo-Darwinism’. It combines the ideas of
Darwin with the discoveries of Mendel and forms the basis of
modern evolutionary science.
35. Vestigial organ
Any part of an organism that has diminished in size during its
evolution because the function it serves has decreased in
importance, eg. the appendix in humans.