SECTION 7
EVOLUTION
The theory of evolution: An idea about origins
- Evolution: process by which populations change over time to adapt to changes in the environment.
- Scientific theory vs hypothesis: A theory is an explanation of the natural world that is well - tested by facts,
hypotheses and laws. > can be repeatedly tested and verified in accordance with scientific method.
Hypothesis Theory
- Idea based on observations - Accepted hypothesis
- May be changed from new evidence - Explanation for observations
- Testable - Body of evidence confirmed often
Biological evolution:
Why does this change occur? Alternation of the genotype and the transfer of these altered genes to the next
generation.
Micro evolution: change in gene frequency within a population.
Macro evolution: Development of new life forms from pre-existing ones over a long period of line.
MICRO MACRO
Time span Short time period, seen over few Over many generations
generations
Scale Small scale Large scale
Result Change within species New life forms
Evolution is a theory because it emerges from multiple lines of evidence:
Lines of evidence in evolution:
1. Fossil record
2. Biogeography
3. Genetics
4. Comparative anatomy
5. Embryology
6. Vestigial organs
, FOSSIL RECORD
- Palaeontology = study of prehistoric life ( evidence of micro and macro evolution)
The fossil record provides detailed information and evidence of systemic change through time descent with
modification.
- Different fossils are found in different rock layers with the oldest fossils on top. 3.5 bil years old
Bias of fossil record:
- Very few organisms become fossils, hard - bodies = most likely
- Most fossils are aquatic animals ( large groups have no record.)
MOULD BODY TRACE UNALTERED
Hardened hollow in shape Fossilisation of body, Marks made by ancient Remains covered in
of organism skeleton, teeth etc. organism natural preservatives
BIOGEOGRAPHY
- Study of past and present distribution patterns of biological diversity and their causes.
> Continental drift: separation of major land masses over geologic time (Pangea)
Alfred Wegener: scientist who proposed continental drift in the early 20th century.
- His idea = one super continent (pangea) that drifted apart to current location.
IMPORTANCE: explains why related species are on different continents - ostrich and emus
EVOLUTION
The theory of evolution: An idea about origins
- Evolution: process by which populations change over time to adapt to changes in the environment.
- Scientific theory vs hypothesis: A theory is an explanation of the natural world that is well - tested by facts,
hypotheses and laws. > can be repeatedly tested and verified in accordance with scientific method.
Hypothesis Theory
- Idea based on observations - Accepted hypothesis
- May be changed from new evidence - Explanation for observations
- Testable - Body of evidence confirmed often
Biological evolution:
Why does this change occur? Alternation of the genotype and the transfer of these altered genes to the next
generation.
Micro evolution: change in gene frequency within a population.
Macro evolution: Development of new life forms from pre-existing ones over a long period of line.
MICRO MACRO
Time span Short time period, seen over few Over many generations
generations
Scale Small scale Large scale
Result Change within species New life forms
Evolution is a theory because it emerges from multiple lines of evidence:
Lines of evidence in evolution:
1. Fossil record
2. Biogeography
3. Genetics
4. Comparative anatomy
5. Embryology
6. Vestigial organs
, FOSSIL RECORD
- Palaeontology = study of prehistoric life ( evidence of micro and macro evolution)
The fossil record provides detailed information and evidence of systemic change through time descent with
modification.
- Different fossils are found in different rock layers with the oldest fossils on top. 3.5 bil years old
Bias of fossil record:
- Very few organisms become fossils, hard - bodies = most likely
- Most fossils are aquatic animals ( large groups have no record.)
MOULD BODY TRACE UNALTERED
Hardened hollow in shape Fossilisation of body, Marks made by ancient Remains covered in
of organism skeleton, teeth etc. organism natural preservatives
BIOGEOGRAPHY
- Study of past and present distribution patterns of biological diversity and their causes.
> Continental drift: separation of major land masses over geologic time (Pangea)
Alfred Wegener: scientist who proposed continental drift in the early 20th century.
- His idea = one super continent (pangea) that drifted apart to current location.
IMPORTANCE: explains why related species are on different continents - ostrich and emus
