The binomial system of names for species
is universal amoung biologists and had
been argreed and delevloped
When species are discovered they are given a scientific
name using the binomial system
Taxonomists classify species using a hirarchy of taxa
Domain, Kingdom, Phyum, Class, Orders, Family, Genus, Species
The domain for species is either Archaeans, Bacteria and
Eukaryota
Human:
Eukaryota.
Animalia,
Chordata,
Mammalia,
Primate.
Hominidae.
Homo.
Sapiens
Pine trees.
Plantae,
Pinophyta.
Pinospioda.
Pinales.
Pinaeae.
Pinus.
Pinus
The genus and accompanying higher taxa consists of all the species that have evolved
from one common ancestral species
Taxonomists sometimes reclassify groups of species when new evidence
shows that a previous taxon contains species that have evolved from a
different ancestral species
Natural classification help in identification of species and allow the prediction of characteristics
shared by species with a group
Cladistics
A clade is a group of organisms that have evolved
from a common ancestor
Evidence for which species are part of a clade can be
obtained from a base sequence of a gene or a
corresponding amino acid sequence of a protein
Cladograms are tree diagrams that show the most probable sequence of
divergence in clades
There is a positive correlation between the number of
differences between two species and the time since they
diverged from a common ancestor
Traits can be Analogous or
Homologous
Analogous structures are similar because of convergent evolution
Homologous structures are similar because of similar ancestry
Evidence from cladistics has shown that classification of some
groups based on structure did not correspond with the
evolutionary origins of a group or species
Natural selection
Natural selection can only occur if there is a variation
among members of the same species
Mutations, meiosis and sexual reproduction cause variation between
individuals in a species
Mutations is the original point of variation. As new
alleles cause mutations
Every cell produced by meiosis has
a different combination of alleles.
By crossing over
The fusion of male and female gametes create a single combination of
alles
Adaptations of characteristics that make
an individual suited to it's environment and
way of life
Species tend to produce more offspring than the
environment can support
Individuals that reproduce pass on characteristics to
their offspring
Those better adapted to the environment tend to
survive and produce more offspring
Those less adapted to the environment tend to not survive and
not produce as much offspring
Natural selcetion increases the amount of characteristics that make an individual
better adapted and decrease the amount of other characteristics leading to a
change within the species