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Sampling methods Daphnia Random samples with a smaller collection beaker 50 ml Since the volume sampled is smaller than the container several samples should be taken and then averaged Sample 1 : 1 daphnia Sample 2 : 5 daphnia Sample 1 : 1 daphnia Sampling Daphnia Sample 1 : 1 daphnia Sample 2 : 5 daphnia Sample 1 : 1 daphnia 7/5 = 2.3 daphnia / 50ml =.045 daphnia / ml Total volume = 4000 + 500ml .045 daphnia / ml * 4500 ml = 210 daphnia Scientific Revolution Genetic Engineering refers to the process of moving genes from one organism to another. Having major impact on medicine and agriculture. Random grids: Sampling Hydra select three grids count the number of hyra Hydra/ grid 1 0 0 .33 hydra /grid 30 grids cover the container. .33 hydra/grid * 30 = 10 hydra Recombinant DNA is DNA taken from two different sources and fused into a single DNA molecule. Special DNA cutting enzymes, called restriction enzymes, cut the DNA at specific sites. Recombinant DNA technology has extensive applications in developing pharmaceuticals. The first drug created using recombinant DNA was human insulin. Piggyback Vaccine Transgenic Golden Rice Other Genetic Techniques Polymerase Chain Reaction (PCR) Other Genetic Techniques DNA Fingerprinting Need a restriction enzyme that will cleave known segments of DNA Restriction enzymes specific for organism DNA fragment migration through the gel dependent upon fragment size Bands do not represent genes Genomic Time Line First free-living organism was the bacterium Haemophilus influenzae sequenced in 1995. 1,830,137 base pairs First eukaryotic genome was baker’s yeast Saccharomyces cerevisiae. 13,000,000 base pairs First animal was nematode C. elegans (1998). 100,000,000 base pairs Human Genome Project 1990 American geneticists embarked on attempt to map and sequence entire human genome (3.2 billion base pairs). DNA fragment of unknown sequence is amplified, mixed with a primer and supply of bases, and four different chain-terminating tags. After heated, mixture will contain series of fragments of different lengths. Human Genome Project Fragments separated according to size by gel electrophoresis. Radioactively labeled and visualized on x-ray film, and sequences read by humans, or automated systems. Genomic Strategies Original plan for Human Genome Project was systematic and conservative using detailed maps of each chromosome and then cloning fragments into bacterial plasmids. May 1998, Craig Venter proposed shotgun sequencing which skipped the mapping step and chopped the entire human genome. Both research groups finished in June 2000. Human Genome Characteristics Geography 30,0000-40,000 genes Fragmented into exons and introns. Not distributed evenly over the genome. Chromosome size is not a clear indication of number of genes. Proteomics Bioinformatics Utilizing molecular genetics and powerful computational analysis to predict what sort of protein a particular sequence encodes. Proteomics Cataloging and analyzing every protein in the human body. Protein arrays are being developed to study all an organism’s proteins. Origin of Life • Three possibilities for the appearance of first living organisms on earth: – Extraterrestrial origin – Special creation – Evolution • All life is composed of the organic macromolecules: carbohydrates, proteins, Lipids and nucleic acids. Origin of life • Scientists suspect first macromolecules were RNA molecules. • First cells may have aggregated spontaneously. • Miller and Urey experiment • Early earth conditions • fossil evidence refutes findings • Environment was – No oxygen not conducive to No ozone may have – SH2 gas life originating not been present in – NH3 from the high enough amounts – CH4 primordial liquid – Bubble model proposes key chemical processes generating the building blocks of life took place within bubbles on ocean’s surface. • Before 1.7 billion years ago, only prokaryotes found in fossil record. – First microfossils (eukaryotes) appear in fossil record 1.7 billion years ago. How Cells Arose • Endosymbiotic Theory – Energy-producing bacteria formed symbiotic relationship with early eukaryotic cells. Eventually evolved into mitochondria. Pelomyxa palustris Evolution of Plants Chapter 16 Outline • • • • Adapting to Terrestrial Life Vascular Plants Seedless Vascular Plants Seed Plants – Gymnosperms – Angiosperms • Flowers – Dicots and Monocots – Seed Dispersal Stromatolites(fossilized algae and phytoplanton Adapting to Terrestrial Living • Green algae that were probably the ancestors of today’s plants are aquatic organisms not well-adapted to living on land. – Had to overcome three challenges: • Minerals absorption from rocky surfaces • Water conservation • Reproduction on land Adapting to Terrestrial Living Adapting to Terrestrial Living • Mineral Absorption – symbiotic fungi – Plants require relatively large amounts of six inorganic minerals: • Nitrogen, potassium, calcium, phosphorus, magnesium, and sulfur. – Mycorrhizae Adapting to Terrestrial Living • Water Conservation – Cuticle - watertight outer covering. • Stomata - gas and vapor exchange. Adapting to Terrestrial Living • Reproduction on Land – Due to immobility, gametes must avoid drying while they are transferred by wind or insects. • Spore Development – Generation alteration • Sporophytes - diploid generation • Gametophyte - hapolid generation Evolution of Vascular System • Terrestrial plants are required to carry water up from roots to leaves, and carbohydrates down from leaves to roots. – Vascular System • Specialized strands of connected hollow cells. – Nine of Twelve living plant phyla are vascular. Nonvascular Plants • Only two phyla of living plants lack a vascular system: – Liverworts (Hepaticophyta) – Hornworts (Anthocerophyta) • Simple Vascular Systems – Mosses were first plants to evolve strands of specialized conduction cells. • No specialized wall thickening. Evolution of Vascular Tissue • Appeared approximately 430 mya. – Grew by cell division at the tips of stem and roots (Primary Growth). • About 380 mya vascular plants developed a growth in which a cylinder of cells beneath the bark divides, producing new cells around plant’s periphery (Secondary Growth). Leaf Vascular System Copyright © McGraw-Hill Companies Permission required for reproduction or display Vascular tissue Xylem – water transport Phloem – food transport Vascular tissue – secondary growth Seedless Vascular Plants • Most abundant of the four phyla of seedless vascular plants contain ferns with about 12,000 living species. – Have both gametophyte and sporophyte individuals, each independent and self-sufficient. • Gametophyte produces eggs and sperm. • Sporophyte bears and releases hapolid Seed Plants • Seed - Embryo cover that offers protection of embryonic plant at its most vulnerable stage. – Male and Female gametophytes • Male - microgametophytes (pollen grains) arise from microspores. • Female - megametophytes contain eggs and develop from megaspores produced within ovule. – Pollination - transfer of pollen.