MULT10011 Lecture Notes - Lecture 2: Cell Membrane, Heredity, Hydrophile
15 Jun 2018
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L.E.U – Lecture 2
Evidence of evolution and natural selection
Evolution is a two-step process:
1. Variability
2. Ordering that variability by natural selection
Darin’s three obserations
• Individuals in a population vary → fitness
• Pass on traits to offspring → heredity
• Never enough resources --? Competition for survival and reproduction
Variability
• Individuals in a population are not identical
• Different size, colour, speed, strength etc.
• Certain traits are better suited to an environment than others
Heredity
• A mechanism whereby offspring inherit most of their parents traits
• This is the so-called program from PICERAS as it is the instructions for how the
organism will be built
• Dari didt ko ho heredit atuall orked, ut Medel figured out soe
rules through studies
Competition and ability to reproduce
• A variant with superior fitness can outcompete a less fit variant
Species
• No universal agreement on the definition
• Many biologists go by the biological species definition that states that individuals of
the same species can breed successfully
o E.g. crossing a horse with a donkey produces infertile offspring -→ different
species
o There are problems though → bananas reproduce asexually – does this mean
each on is a different species?
• Not appliale to orgaiss that dot hae a se, i.e. ateria
Homology- derived from a common ancestral feature
• Different animals having the same bones, but they have different uses
Unity of biochemical processes
• All organisms share main biochemical reactions
• E.g. all organisms have genetic material (Program), that contain the instructions
(software) on how the organism will develop
• E.g. organisms also have hardware to carry out these instructions – the proteins
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