BIOA01 – Lecture 02 – Intro TO Biology AND THE TREE OF LIFE PDF

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BIOA01 – LECTURE 02 – INTRO TO BIOLOGY AND THE TREE OF LIFE -SEPTEMBER 4 2014 / SEPTEMBER 5 2014 BIOLOGY IS THE STUDY OF LIFE Are viruses alive?  Threat to humans  Traits like humans: ONLY INSIDE A HOST = THEREFORE MOST SAY NOT ALIVE o DNA/RNA o Reproduce o Evolve o Adapt  Unicellular organisms can do all this by themselves whilst viruses can only do it in a host  Parasites use host as an environment o Not hijacking the host material Properties of life: Emergent Properties - Complex patterns that are the outcome of simple processes  Cells: Help maintain life o Cells are the unit of life o Cells allow organisms to have an internal environment separate from the external life  Most basic function  Harness and Utilize Energy: Help maintain life o Pumping chemicals through cell membrane o Pumping inside cell o All life forms harness and utilize energy  Reproduce: Evolution by natural selection o Organisms that could produce favoured themselves by leaving copies of themselves for generations o All life is capable of evolution  Respond to Stimuli: Evolved through natural selection o Survival o If they cant recognize light and prey they don’t leave many copies of themselves o Traits disappear o Evolved through natural selection o Organisms that respond to environmental stimuli will be favoured by natural selection o Plants respond to stimuli (one type or another) o Response to external environment  Exhibit Homeostasis: o Optimization of environmental processes

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o Constant pH and temperature benefit organisms o Must be predictable for organism to thrive o Inability to maintain homeostasis causes damages to organisms o Response to internal environment Grow and Development: o Process of development o More careful ways of processing the internal and external environment o Not creating new copies of yourself, just changing yourself Evolve: o Adapt to their natural environment o Reproduction in that environment creates basis for future o If environment changes then adaptation and features change on lineage

Conspiracy Theories of Virus Life: Are some viruses on the line between life and nonlife?  Some viruses are as large as bacteria  Huge number of genes  Require only 4 genes to survive  Many genes only thought to be only in cellular organisms  Mamaviruses can get sick o Attacked by virophages Emergent property examples:  School of fish responding to diver o Move together o As a cloud o Respond to stimuli of diver  Termite nests o Size and shape allow CO2 in o Complex shape of simple individual behaviours History of Life:  Origins: o Oparin-Haldane Hypothesis:  Chemicals in atmosphere of primordial earth and energy = formation of organic molecules required for life  LEARGE CONCENTRATIONS OF HYDROGEN, METHANE and ammonia and water vapor = reducing earth atmosphere  No oxygen = no ozone o Deep-Sea Vent Hypothesis  Chemicals in the deep ocean lead to a reducing environment  Vents and lot of heat energy to the cracks and crust of the Earth  Creating hot water from surface of Earth (under-sea cracks)  Nutrients

o Extraterrestrial Origin  Organic molecules required for life originated in space  Brought by meteor impact o Panspermia Hypothesis (Seeds from space)  Life arose from outer space  Life was seeded by these life forms  No real evidence  Insufficient time for abiotic processes to generate life  Life could possibly survive in space for a long periods of time (extremophiles)  Mars  Frozen water o Life maybe under the polar ice  Antarctica  Found an ecosystem under the polar ice  No light  Could be generations for a 120000 years – one million years 2.2 Tree of Life:  Earth was made 4.6 billion years ago  All life generated from a single common ancestor  Earliest form of life were heterotrophs  Autotrophs Organisms – Create their own energy o First autotrophs used sulfides and generations from rocks o May have looked like extremophiles o May have lived in the deep sea o Break down rock for energy o Restricted because they needed those minerals o Water and light to photosynthesize  Anywhere there is water they can survive  Took long for unicellular and eukaryotes to evolve  Evolved from one another  Old organisms help with oxygen build up  Evidence shows that dinosaurs had feathers!  The tree of life is the genealogical relationships among organisms  A phylogenetic tree is a branching diagram representing evolutionary relations among organisms o Opposite of the family tree o At the root or bottom of the tree is the most ancient organisms where all other organisms came from o Bacteria, Achaea, Eukarya are the domains of life o LUCA (Last Universal Common Ancestor) at the bottom of the tree of life, then common ancestors, then plants, fungi and animals o Work in progress

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Many details we do not know about (order of evolution)

Themes of Tree of Life: o 1 - Biotic and Abiotic Environment changes over time  As environments change the traits in the individuals also change that can change the diversity on Earth  Evolution by natural selection  Populations in a particular area, changing to match that environment  New niches  Oxygen in the ozone layer  Living on land o 2 - Less complex doesn’t mean inferior  Just because they are more ancient doesn’t mean they are more inferior  No goals in evolution o 3 – The tree of life is not linear  The linearity shows the tree of life and scale of time  Some of those species didn’t make it to the present day  Lineages develop new traits, survive, then extinct  The tree of life is more like a bush  Some branches failed  Some disappeared species have no living decedents  Evolutionary splits in the lineages which causes extinction  Many experiments and modifications 2.3 Common Ancestry of Life: Evidence = Common physiological/genetic organization  Cells with lipid bilayers  Genetic system based on DNA  Common system of information transfer (DNA to RNA to Protein)  Protein assembly from amino acids via translation by mRNA and tRNA using ribosomes  Protein as major structural and catalytic molecules  ATP is molecule of chemical energy  Metabolic breakdown of glucose via glycolysis to form ATP...