BIOL1030 Final: BIOL1030 Study Guide
BIOL1030 Study Guide
Biodiversity & Environment
Semester 1, 2012
Please note that LIFT does not warrant the correctness of the materials contained within the notes. Additionally, in some cases,
these notes were created for previous semesters and years. Courses are subject to change over time, both in content and scope of
assessment. Thus the information contained within may or may not be assessed this semester, or the information may have been
superseded. These notes reproduce some copyrighted material, the use of which has not always been specifically authorised by
the copyright owner. We are making these materials available for the purposes of research and study and as such believe that this
constitutes fair dealing with any such copyrighted material pursuant to s 40 Copyright Act 1968 (Cth).
Module 1: Biodiversity
Lecture 3, 2/03/12: Global Biodiversity, The Origins of Life,
and Natural Selection
The origin of life: SUMMARY
ď€ Global biodiversity is immense, poorly and unevenly understood and
under threat
ď€ Between 4.5 and 3.6 billion years ago, life got started on earth
ď€ Scientists favor evolution from ancient atmosphere and seas through
grades of self assembling macro-molecules
ď€ Most think it passed through an RNA-world stage that would have been
subject to natural selection
ď€ Once natural selection could work… BANG!
ď€ Other possible origins (comets, meteorites?)
ď€ Locality on earth is debated (shallow, deep sea?)
ď€ 3.6 billion years ago, a blob called LUCA (Last Universal Common
Ancestor) was floating around somewhere, and everything is descended
from it… including YOU!
Biodiversity key facts
ď€ Total of 10 – 100 million species globally, only 1.8 million named (1
million of those are insects)
ď€ The Earth has vast biodiversity
ď€ The biodiversity is very unevenly known
ď€ We are said to be part of the “sixth Great Extinction” (through loss of
habitat, loss of biodiversity)
Our theory: That life arose from non-life by processes of evolution. The evolution
idea arose from an accumulation of observation and experiments
ď€ Evolution is a theory (not a hypothesis)
ď€ The theory covers everything that has emerged over time
What is life?
ď€ Life is composed of organic matter that is capable of undergoing
reproduction and natural selection
ď€ To reproduce, a living system must: accumulate biomass (get bigger), and
organize it into coherent, inheritable biological structures
ď€ For natural selection to operate, a living system must: generate
inheritable variation (can’t be exactly the same, variations must be passed
down through generations)
“Traces” of evolution:
ď€ Why we have a bit of a tail
ď€ Why we have gill slits as embryos
ď€ Why we have back problems
ď€ Why everything has DNA
Evolution:
ď€ â€śInheritable variation” leads to evolution
ď€ â€śInheritable variation” encoded in the genome allows for successful
individuals and populations to be selected in favor of less successful ones
(i.e. the variations are heritable)
ď€ This process has led to the existence of the millions of separate species on
Earth
SEE NOTES for proposed steps of how cellular life began
ď€ 4.5 BYA: formation of Earth
ď€ 4.2 BYA: stable hydrosphere
ď€ 4.2-4.0 BYA: prebiotic chemistry, organic building blocks – many
molecules required for life can be generated in the physiochemical
conditions of early life.
ď€ 4.0 BYA: pre-RNA world, chemical “evolution” – creation of complex
polymers. Compartmentalized, self-replicating chemical systems may
have originated here. Natural selection?
ď€ 3.8 BYA: RNA world – the information-carrying molecule (and catalyst).
Natural selection is now in operation. RNA created through natural
selection?
ď€ 3.6 BYA: first DNA/protein life – LUCA appeared
When did cellular life begin?
ď€ Determining the origination of life requires boundaries to be set
ď€ Lower boundary 4.3BYA (first point life could have existed): determined
by geological studies of formation of Earth.
ď€ Upper boundary 3.5BYA (when life is definitely present): determined by
fossil and geochemical records.
How did cellular life begin?
ď€ i.e. how did living systems originate from non-living ones? What were the
key innovations?
ď€ Approaches:
> Simulate the early Earth conditions or early proto-living systems
> Compare modern organisms to identify ancient features in the
earliest life forms
ď€ In deep seas more complex chemicals were developed
ď€ By random chance and chemistry, larger molecules were formed
ď€ SEE NOTES for proposed steps of how cellular life began
Miller-Urey experiment (1953):
ď€ Abiotic synthesis of molecules under conditions thought to represent
early Earth (absence of oxygen)
ď€ Produced organic compounds!
ď€ See notes for diagram of set-up
Document Summary
Please note that lift does not warrant the correctness of the materials contained within the notes. Additionally, in some cases, these notes were created for previous semesters and years. Courses are subject to change over time, both in content and scope of assessment. Thus the information contained within may or may not be assessed this semester, or the information may have been superseded. These notes reproduce some copyrighted material, the use of which has not always been specifically authorised by the copyright owner. We are making these materials available for the purposes of research and study and as such believe that this constitutes fair dealing with any such copyrighted material pursuant to s 40 copyright act 1968 (cth). Lecture 3, 2/03/12: global biodiversity, the origins of life, and natural selection. Global biodiversity is immense, poorly and unevenly understood and under threat. Between 4. 5 and 3. 6 billion years ago, life got started on earth.
