These notes cover evolution for matric life sciences. They are IEB curriculum and were made in 2020. They contain images and examples. They include notes on Darwin and Lamarck's theories. They include examples of inbreeding, outbreeding, allopatric and sympatric speciation as well as natural and ar...
A hypothesis is an informed or educated assumption
- It provides a solution to a problem
- It provides an explanation of a specific phenomenon
It is based on scientific evidence and research
It can be tested by experiments or repeated observation
- Depending on the results it is either rejected or accepted
Theory
A theory is a well-substantiated explanation or hypothesis
- It makes sense of a natural phenomenon
It is based on scientific evidence
- It can be tested and confirmed by independent researchers
It is developed and changed or replaced as new evidence is observed
Evolution is a theory
- It is based on a series of hypotheses
- It has been tested and verified over time
, Evolution
Evidence of evolution
Fossil record
- Indicates the climate and environment from the past
- Few individuals fossilise
o Very specific conditions are needed for fossilisation
- Earlier, simpler fossils are found in deeper, older rock
o Recent, complex fossils are found in upper, newer rock
o This indicates the order in which evolution occurred
- Older rock has less biodiversity than new rock
o This indicates biodiversity increased over time
- The fossil record contributes to the complete compilation of
the geological timescale
Modification by descent
- Modification of limbs to adapt to environment
- Modification can occur within a species or within
relatives of a species
o Can result in speciation
ANALOGOUS STRUCTURES
, Evolution
Homologous structures (Divergent evolution)
- Same body plan with different functions
- Can be traced back to a common ancestor
- Develop independently
o Suited to a specific habitat
Analagous Structures (Convergent evolution)
- Same function but different structure
- Adapted to similar environments
- No common ancestor
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