BIOL1003 Lecture Notes - Mendelian Inheritance, Genetic Drift, Dactyly
Chap 1
• Example of evolution:
o70 million years ago the Wollemi pine grew around Australia, New
Zealand and Antarctica and reproduced sexually, producing many seeds
oNow there are only a few hundred and they only exist in one Australian
national park and they reproduce asexually by producing new stems
which survive when old ones die
oThe survival of the Wollemi pine for this long is due to it using different
reproductive strategies which allow it to evolve to the changing
environment as the climate changed
New properties emerge at successive levels of biological organisation
• Levels of biological organisation
oBiosphere- all the environments on Earth inhabited by life
oEcosystems- all the living and nonliving components of an area e.g.
grasslands, eucalypt forest, deserts, coral reefs
oCommunities- the entire array of organisms inhabiting an ecosystem
oPopulations- the individuals of a specific species in a specified area
oOrganisms- individual living things
oOrgans and organ systems
oTissues
oCells
oOrganelles
oMolecules
• Emergent properties
oNovel properties which emerge at each level that are absent from the
preceding level
oThese are due to the arrangement and interactions of parts as complexity
increases
oIsolated components of living systems lack a number of significant
properties that emerge at higher levels of organisation
oE.g. photosynthesis will not take place in a disorganised test-tube mixture
of chlorophyll and other chloroplast molecules
• Systems biology- the exploration or a biological system by analysing the
interactions among its parts
• The cells of two groups of single-celled microorganisms, bacteria and archaea are
prokaryotic and all other forms of life are composed of eukaryotic cells
• Prokaryotic cells lack a nucleus or other membrane-enclosed organelles
Life’s processes involve the expression and transmission of genetic information
• Gene expression: Genes RNA amino acids proteins
• Genome: the entire set of genetic instructions that an organism inherits
• Genomics: studying a whole set of gens
• Proteomics: the study of proteins and their properties
• Proteome: the entire set of proteins expressed by a given cell or group of cells
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• Bioinformatics: the use of computational tools to store, organise and analyse the
huge volume of data that results from high-throughput methods
Life requires the transfer and transformation or energy and matter
The input of energy, primarily from the sun, and the transformation of energy
from one form to another makes life possible
Plant leaves absorb sunlight, and molecules in the leaf convert the energy to
chemical energy of food, such as sugars, produced during photosynthesis
The chemical energy in the food molecules is then passed along by plants and
other photosynthetic organisms (producers) to consumers
Energy flows one way through an ecosystem- usually entering as light and exiting
as heat
Chemicals are recycled within an ecosystem
From ecosystems to molecules, interactions are important in biological systems
Some interactions are mutually beneficial e.g. the “cleaner fish” that hovers
around the sea turtle feeds on parasite that would otherwise harm the turtle,
while it gains food and protection from prey
Interactions between components that make up living organisms- organs,
tissues, cells and molecules- are crucial to their smooth operation e.g. production
of insulin after eating a meal and getting high blood-glucose levels, enzymes
Feedback regulation- the output, or product of a process regulates the process
oNegative feedback- the response reduces the initial stimulus e.g. insulin
signalling
oPositive feedback- the end product speeds up its own production e.g.
blood clotting in response to an injury (platelets)
Evolution accounts for the unity and diversity of life
Three kingdoms differ by their modes of nutrition
oPlants produce their own sugars and other food molecules by
photosynthesis
oFungi absorb dissolved nutrients from their surroundings
oAnimals obtain food by eating and digesting other organisms
Darwin’s book “On The Origin of Species by Means of Natural Selection”
oDescent with modification
oNatural selection is an evolutionary mechanism for that to occur
Other people had also made observations, but Darwin saw how they all fitted
together
Darwin’s three observations from nature:
oIndividuals in a population vary in their traits, many of which are heritable
oA population can produce far more offspring than can survive to produce
offspring of their own- competition is inevitable
oSpecies generally suit their environments
Example- the pentadactyl limb and bones, joints, nerves and blood vessels are all
similar between bats, humans, horses, whales (same basic skeletal elements but
have become adapted for different functions)
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Natural selection by its cumulative effects over long periods of time could cause
an ancestral species to give rise to two or more descendent species e.g. Darwin’s
Finches in the Galapagos Islands- evolved to different islands
In studying nature, scientists make observations and form and test hypotheses
Scientists use a process of inquiry that includes making observations, forming logical,
testable explanations (hypotheses) and testing them
Induction entails reasoning from a set of specific observations to reach a general
conclusion
Deductive reasoning involves logic that flows in the opposite direction, from the
general to the specific
No amount of experimental testing can prove a hypothesis beyond a shadow of
doubt- simply supports the hypothesis
Science cannot test the supernatural or religion
Example:
oTwo mice groups in one species- one lives on the Florida beach with white
sand dunes and is light in colour, and the other mouse lives inland on darker
soil and is darker coloured- adapted to camouflage to the environment
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Document Summary
Example of evolution: 70 million years ago the wollemi pine grew around australia, new. New properties emerge at successive levels of biological organisation. Systems biology- the exploration or a biological system by analysing the interactions among its parts. The cells of two groups of single-celled microorganisms, bacteria and archaea are prokaryotic and all other forms of life are composed of eukaryotic cells: prokaryotic cells lack a nucleus or other membrane-enclosed organelles. Life requires the transfer and transformation or energy and matter. The input of energy, primarily from the sun, and the transformation of energy from one form to another makes life possible. Plant leaves absorb sunlight, and molecules in the leaf convert the energy to chemical energy of food, such as sugars, produced during photosynthesis. The chemical energy in the food molecules is then passed along by plants and other photosynthetic organisms (producers) to consumers. Energy flows one way through an ecosystem- usually entering as light and exiting as heat.
