BIOL10002 Lecture Notes - Lecture 1: Ontogeny, Biogeography, Mnemonic
Lecture 1: Foundations of Biology
Evolution:
● All life evolved from pre-existing life
● Homology: things with same evolutionary ancestry; common ancestral features; e.g. human arm, dog foreleg, seal flipper are
homologous features despite different functions therefore had a common ancestor
● Fossils create the fossil record which is strong evidence for evolution
● Phylogeny: development is a fast action replay of our evolution eg. embryo to human mimics evolution
● We all start out as one cell; webbing between fingers degenerates by programmed cell death to free digits
● Biogeography also supports evolution e.g. unique Australian flora and fauna due to protected evolution on an isolated continent
● DNA contains the history of evolution; organisms closely related have similar DNA (e.g. gorilla & human 99% identical); can
compare genes to define relationships
Ontogeny: the development of an individual organism or
anatomical or behavioural feature from the earliest stage to
maturity
Phylogeny: the evolutionary development and diversification of a
species or group of organisms, or of a particular feature of an
organism
Foundations of Biology
1st foundation: darwin’s three observations
2nd foundation: unity of biochemical
processes
3rd foundation: cell theory
Individuals in a population vary →fitness
Pass on traits to offspring →heredity
Never enough resources→competition for
survival/reproduction
Leads to natural selection of traits suitable
for environment
Evolution as a two step process:
1. Variability
2. Ordering that variability by natural
selection
Mnemonic: ICE AGE: Inherited variation,
competition, environmental pressures,
All organisms share main biochemical
reactions eg. all organisms have DNA that
contains the instructions on how that
organism will develop, organisms also have
hardware to carry out the instructions
(proteins)
All known living things are made up of one
or more cells
All living cells arise from pre-existing cells
by division
The cell is the smallest unit of life
The cell is the fundamental unit of structure
and function in all living organisms
Cells contain hereditary information (DNA)
passed from cell to cell during division
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adaptation, genetic variation, evolution
Lecture 2: Prokaryotes
Life depends on prokaryotes: archaea allows herbivores to break down sugars in plants, bacteria in intestines make vitamins, harmless
bacteria on skin protect us from invaders, gut microbiome (2-3kg of bacteria in humans) has consequences on general health
Prokaryotes used in food production: e.g. fermented foods produced by action of microbes and cocoa pods which ferment to form
chocolate
More than 50% of earth’s free oxygen generated by Bacteria; 70% of biologically available nitrogen produced by bacteria
Prokaryotes
DNA sequencing also discovered groups (domains) of prokaryotes: Bacteria, Archaea
Eukaryotes
Large (still microscopic)
Multicellular
Nucleus
Division of labour in cytoplasm
(compartmentalization):
endomembrane system,
endoplasmic reticulum, golgi,
cytoskeleton: microtubules +
microfilaments + intermediate
filaments, motor proteins and
movement
25-30nm ribosomes
Different organisms have
different numbers of
chromosomes
Eukaryotic flagella:
microtubules and dynein
motors; microtubules fixed at
Bacteria
Both
Archaea
No proteins attached to
DNA
One surrounding
membrane: gram positive
Two surrounding
membranes: gram negative
with wall between
Diseases caused by
Bacteria: pharyngitis,
impetigo, anthrax etc.
Microscopic
1-10um
Singular DNA, nucleoid, circular
chromosome
Cell wall of peptidoglycan
No nucleus
17-23nm ribosomes
Binary fission: prokaryotic cell division:
constricting ring pinches parent cell into
two; daughter cells identical, received
copied DNA, FtsZ: protein that helps in
pinching a cell in two during binary fission
(Filament Temperature Sensitive)
Prokaryotic flagella: for motility, a long thin
filament, corkscrew action (rotating shaft
design, goes at 6000 rpm but often only
Proteins (histones)
attached to DNA
Our nearest ancestors in
the microbial world
Do not cause any
diseases like bacteria do
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Homology: things with same evolutionary ancestry; common ancestral features; e. g. human arm, dog foreleg, seal flipper are homologous features despite different functions therefore had a common ancestor. Fossils create the fossil record which is strong evidence for evolution. Phylogeny: development is a fast action replay of our evolution eg. embryo to human mimics evolution. We all start out as one cell; webbing between fingers degenerates by programmed cell death to free digits. Biogeography also supports evolution e. g. unique australian flora and fauna due to protected evolution on an isolated continent. Dna contains the history of evolution; organisms closely related have similar dna (e. g. gorilla & human 99% identical); can compare genes to define relationships. Ontogeny: the development of an individual organism or anatomical or behavioural feature from the earliest stage to maturity. Phylogeny: the evolutionary development and diversification of a species or group of organisms, or of a particular feature of an organism.
