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Key concepts for today – Part 2: Diversity of the biosphere – - The biosphere is a hierarchy, but the levels are nested. - Emergent properties arise at each level of organization. - Biologists like to find order and define relationships. Evolution – how diversity arose - A blind watchmaker of nature, evolution happens by tinkering, = engineering. - It’s all about being fit. LIFE’S HIERARCHY Bacteria biosphere Eucarya BACTERIA/ARCHAEA ecosystem community population organism [cell] molecule atom EUKARYA Archaea LIFE’S HIERARCHY Bacteria biosphere Eucarya BACTERIA/ARCHAEA EUKARYA Single-celled ecosystem community population organism [cell] organelle molecule atom Archaea LIFE’S HIERARCHY Bacteria biosphere Archaea Eucarya BACTERIA/ARCHAEA EUKARYA Single-celled Multicellular (plants/animals/fungi) ecosystem community population organism [cell] organelle molecule atom organ tissue organ system LIFE’S HIERARCHY Bacteria biosphere Archaea Eucarya BACTERIA/ARCHAEA EUKARYA Single-celled Multicellular (plants/animals/fungi) ecosystem community population organism [cell] organelle molecule atom organ tissue organ system LIFE’S HIERARCHY Bacteria biosphere Archaea Eucarya BACTERIA/ARCHAEA EUKARYA ecosystem community population NESTED – an animal is both a organism and a composite! Organism [cell] organelle molecule atom organ tissue organ system Emergent Properties – properties of one level are not additive, i.e., equal to the sum of their components – new properties and rules emerge that could not have been predicted from full understanding of the lower level – WHOLE GREATER THAN SUM OF PARTS biosphere ecosystem community population organ system organ tissue cell organelle molecule atom In your readings: Cohen (your reader) Math & Biology Davies (PDF, Bi1 Website] Emergent biological principles and the computational properties of the universe. Emergent Properties Emergent properties of bacterial community affect host health Host’s body selects for specific microbes RELATIONSHIPS Limits of RESOLUTION BC– eyes – Aristotle ANIMALS/PLANTS Late 1700s Magnifying lenses (microbes) – all about seeing Anton van Leeuwenhoek ANIMALS/PLANTS/MICROBES Better microscopes – (organelles) – 5 kingdoms – taught [~1960s-2000] ANIMALS/PLANTS/FUNGI/PROTISTS/’MONERA’ [Bacteria/Archaea] RELATIONSHIPS Limits of RESOLUTION BC– eyes – Aristotle ANIMALS/PLANTS Late 1700s Magnifying lenses (microbes) – all about seeing Anton van Leeuwenhoek ANIMALS/PLANTS/MICROBES Better microscopes – (organelles) – 5 kingdoms – taught [~1960s-2000] ANIMALS/PLANTS/FUNGI/PROTISTS/’MONERA’ [Bacteria/Archaea] Sequencing of hereditary molecules 3 domains – taught [~1990 – present] Bacteria Eucarya Archaea ARE WE DONE – have we finally discovered the essence? Maybe not Bacteria Archaea Eucarya Each time biologists are sure they had the final picture - STAY OPEN! THE DNA IS NOT STATIC! IT NATURALLY MOVES AROUND and WE’RE BEGINNING TO MOVE IT AROUND. [END OF Bi1 – Myles Jackson, NYU – ethics in modern biology How did the diversity of the biological world arise? EVOLUTION – the ‘glue’ that joins all of biology - A theme that will run through Bi1 Charles Darwin 1809-1882 Voyage of the Beagle Charles Darwin 1809-1882 Voyage of the Beagle From Darwin’s journal Divergence of the Galapagos finches From Darwin’s journal Divergence of the Galapagos finches UTube video – possible idea for your writing assignment: http://www.youtube.com/watch?v=_UZ5u5sN1WQ Published November 1859 the foundation of evolutionary biology How did the diversity of the biological world arise? WHAT IS EVOLUTION: The change in genetic [DNA] composition (blueprint) of a population over generations Basis – genetic variation, differences in the blueprint, in fitness Fitness (ω) = capacity of a particular genetic makeup (= genotype) to leave offspring to the next generation ω abs = Nafter Nbefore Absolute fitness (ω) of a genotype is defined as the ratio between the number of individuals with that genotype after selection to those before selection. ω > 1, genotype representation in the population increases ω < 1, genotype representation in the population decreases How did the diversity of the biological world arise? MECHANISMS: 1. Changes in the genome Genetic drift – chance creates novelty random changes that accumulate Horizontal gene transfer – transfer of large pieces of DNA from one organism to another 2. Natural Selection – individuals with more advantageous traits at a given time have higher fitness [not acquired within a generation] Change in the genome Frequency of changes in DNA: Error rate in DNA replication: 1 in 50 x 106 DNA damage: >1000 lesions/cell during this lecture HGT: variable – rise on antibiotic resistance Evolution through laboratory experiment DESIGN Frances Arnold Chemical Engineering Darwin was all about natural selection His precepts: 1. Life had a common beginning. It’s written on your genome (sum of all of your genes) Humans: 23,600 genes Graphics by N Glasser Darwin was all about natural selection His precepts: 1. Life had a common beginning. 2. Random variation arises by chance (genetic drift) 3. Selection from the environment (abiotic, biotic) for favorable traits (natural selection) 4. Cumulative over time – new forms 5. Gradual change Punctuated equilibruim – Steven J Gould Long periods of stability and short episodes of change species 3 evolution species 2 species 1 Rapid changes in the environment time KEY INNOVATION – [e.g., development of electricity – light bulb, airplane, computer] in biology, trait that enables a group of organisms to diversify; e.g., hardened forewing of beetles KEY INNOVATION – e.g., hardened forewings (elytra) of beetles Vortex field contour during one cycle of hind wing flapping Le et al. (2010) Numerical investigation of the aerodynamic characteristics of a hovering Coleopteran [beetle] insect. Key concepts for today: Principles of biology – Key concepts that structure the course Diversity of the biosphere – Evolution – how diversity arose Syllabus