Evolution
Random notes
Descent with modification – random genetic mutations
Common descent – all species come from a common ancestor, cannot be seen but concluded by
many facts such as biochemistry and there is no order or complexity from random things
Darwin understood from selective breeding that some animals have been sculpted to thrive in their
environment
Natural selection(which is now observable) – process of random evolutionary changes, these positive
evolutionary changes develop over generations whilst others die out
Def – organisms better adapted to environment tend to survive and reproduce
Antibiotics – kill prokaryote cells
Fitness – how many offspring they have
Evolution through natural selection
Organisms who sexually reproduce will have genetic variation due to mutations so have
different alleles – this is natural selection
Living organisms face selective pressure with predation and competition and some
characteristics are good/useful alleles
Due to a change in environment, some have better characteristics and alleles better suited to
change, so more likely to survive and reproduce, passing on the useful allele to offspring
Others without useful allele less likely to survive and reproduce so die out
Over time more with useful than not useful – the species has evolved
Darwin vs Wallace
Darwin Wallace
Finches beak islands in Galapagos Differences in warning colour of butterflies
On the origin of species
came up with theory of natural selection He did too
Idea focussed on competition between Idea focussed on environmental pressure being
individuals of same species being cause of cause of evolution
evolution i.e. intraspecific competition
Worked with Wallace sharing scientific ideas Worked with Darwin sharing scientific ideas
WallacE – Environment
DArwin – intrAspecific competition
Darwin wrote his theory of evolution when DNA and genes had not been discovered yet. Darwin and
Wallace published their results together on evolution even though they did not always agree with
the mechanisms involved in natural selection. Wallace had lots of evidence to support evolution by
natural selection, but Darwin had lots of evidence on his theory and expanded on it, which is why he
is better remembered.
Impact on modern biology i.e. natural selection:
, Individual organisms within a particular species show a wide range of variation for a
characteristic
Individuals with characteristics more suited to the environment are more likely to survive
and breed successfully
The characteristics that have enabled these individuals to survive have then been passed
onto the next generation
Evidence for evolution
There are 5 main evidences for evolution:
Fossils
Stone tools
Antibiotic resistant bacteria
Pentadactyl limb
Genome and gene sequencing
GASP F
Fossils:
Cranial capacity increases with time – smarter
Longer legs, shorter arms, hand size smaller, taller
Human beings and their ancestors are known hominids
Change in bone structure from fossils such as Ardi (4.4million years) and Lucy(2.2 million years) are
evidence for evolution.
1. Ardipithecus ramidus - Ardi
2. Australopithecus afarensis - Lucy
3. Homo habilis
4. Homo erectus
5. Homo neanderthalensis
6. Homo sapiens
Ardi:
4.4 million years old
Ape-like big toe to climb trees
Long arms and short legs like ape
Brain size same as chimpanzee
Structure of legs – walked upright
Lucy:
Australopithecus afarensis
Arched feet for walking and no big toe
Size arms and legs between ape and human
Brain larger Ardi but similar chimpanzee
Walked upright but more efficient ardi
Random notes
Descent with modification – random genetic mutations
Common descent – all species come from a common ancestor, cannot be seen but concluded by
many facts such as biochemistry and there is no order or complexity from random things
Darwin understood from selective breeding that some animals have been sculpted to thrive in their
environment
Natural selection(which is now observable) – process of random evolutionary changes, these positive
evolutionary changes develop over generations whilst others die out
Def – organisms better adapted to environment tend to survive and reproduce
Antibiotics – kill prokaryote cells
Fitness – how many offspring they have
Evolution through natural selection
Organisms who sexually reproduce will have genetic variation due to mutations so have
different alleles – this is natural selection
Living organisms face selective pressure with predation and competition and some
characteristics are good/useful alleles
Due to a change in environment, some have better characteristics and alleles better suited to
change, so more likely to survive and reproduce, passing on the useful allele to offspring
Others without useful allele less likely to survive and reproduce so die out
Over time more with useful than not useful – the species has evolved
Darwin vs Wallace
Darwin Wallace
Finches beak islands in Galapagos Differences in warning colour of butterflies
On the origin of species
came up with theory of natural selection He did too
Idea focussed on competition between Idea focussed on environmental pressure being
individuals of same species being cause of cause of evolution
evolution i.e. intraspecific competition
Worked with Wallace sharing scientific ideas Worked with Darwin sharing scientific ideas
WallacE – Environment
DArwin – intrAspecific competition
Darwin wrote his theory of evolution when DNA and genes had not been discovered yet. Darwin and
Wallace published their results together on evolution even though they did not always agree with
the mechanisms involved in natural selection. Wallace had lots of evidence to support evolution by
natural selection, but Darwin had lots of evidence on his theory and expanded on it, which is why he
is better remembered.
Impact on modern biology i.e. natural selection:
, Individual organisms within a particular species show a wide range of variation for a
characteristic
Individuals with characteristics more suited to the environment are more likely to survive
and breed successfully
The characteristics that have enabled these individuals to survive have then been passed
onto the next generation
Evidence for evolution
There are 5 main evidences for evolution:
Fossils
Stone tools
Antibiotic resistant bacteria
Pentadactyl limb
Genome and gene sequencing
GASP F
Fossils:
Cranial capacity increases with time – smarter
Longer legs, shorter arms, hand size smaller, taller
Human beings and their ancestors are known hominids
Change in bone structure from fossils such as Ardi (4.4million years) and Lucy(2.2 million years) are
evidence for evolution.
1. Ardipithecus ramidus - Ardi
2. Australopithecus afarensis - Lucy
3. Homo habilis
4. Homo erectus
5. Homo neanderthalensis
6. Homo sapiens
Ardi:
4.4 million years old
Ape-like big toe to climb trees
Long arms and short legs like ape
Brain size same as chimpanzee
Structure of legs – walked upright
Lucy:
Australopithecus afarensis
Arched feet for walking and no big toe
Size arms and legs between ape and human
Brain larger Ardi but similar chimpanzee
Walked upright but more efficient ardi
