EVOLUTION - a change over time
BIOLOGICAL EVOLUTION - genetic changes in the population that are inherited
over successive generations due to natural selection
and ultimately leading to the formation of a new
species
MACROEVOLUTION - the development of new life forms or species from earlier
life forms over many generations (extended geologic
periods)
MICROEVOLUTION - the variation that occurs within a species. Small changes
originate in the gene pool, resulting in small changes in the
genotype of the species that is passed into the offspring
The Theory of Evolution
Evolution is the process by which populations change over time and over many generations
to remain adapted to changes in the environment
Genotypes suitable for the environment will be passed to the next generation
The theory that life on Earth arose from a common ancestor 4,6 billion years ago is
supported by scientists
Scientific Theory| an explanation of aspects of the
natural world that can be
repeatedly tested and verified in
accordance with the scientific
method
Biological Evolution
MACRO-EVOLUTION
MICRO-EVOLUTION The development of new life forms
from pre-existing ones over many
Changes that occur within a species generations
short time period Takes a long time
Adaption of an existing species
(inherited characteristics) E.g) Chickens from Dinosaurs
E.g) MDR - bacteria
, Macro-Evolution
The development of new, highly developed groups of organisms from pre-existing ones
over geological time
Patterns of Macro-Evolution
STASIS ANAGENESIS
The lineage does not change much gradual change within a single evolutionary
for long periods of time B
A
CLADE
Life-form group consisting of a common
EXTINCTION
ancestor and all its descendants
Complete termination of one or
more species due to selective CLADOGENESIS ADAPTIVE RADIATION
pressures/natual disasters
Splitting of lineages bursts of divergence from
a single lineage to give rise
into 2 or more B C to many new species from
species common ancestors
A
Rates of Evolutionary Changes
Two types:
Gradualism PUNCTUATED EQUILIBRIUM
Punctuated Equilibrium
Evolution occurs in sudden
bursts between long periods
of stasis
GRADUALISM
Species evolves gradually (slowly)
Small stages over long periods of time at
a constant rate