BIOS 208 1st Edition Lecture 2Outline of Last Lecture I. Learning ObjectivesII. Themes: Biological Hierarchy & The Cell Is an Organism’s Basic Unit of Structure and Function Outline of Current Lecture I. DNA Structure and FunctionII. The Three Domains of LifeIII. Evolution BasicsCurrent LectureI. DNA Structure and FunctionA. Chromosomes contain most of a cell’s genetic material in the form of DNA (deoxyribonucleic acid).B. DNA is the substance of genes.C. Genes are the units of inheritance that transmit information from parents to offspring.D. The ability of cells to divide is the basis of all reproduction, growth, and repair of multicellular organisms.E. Each chromosome has one long DNA molecule with hundreds or thousands of genes.F. Genes encode information for building proteins.G. DNA is inherited by offspring from their parents.H. DNA controls the development and maintenance of organisms and each DNA molecule ismade up of two long chains arranged in a double helixI. Each link of a chain is one of four kinds of chemical building blocks called nucleotides and abbreviated to A, G, C, and T. An organism’s genome is its entire set of genetic instructions.J. The human genome and those of many other organisms have been sequenced using DNA-sequencing machines.K. Genomics is the study of sets of genes within and between species. The genomics approach depends on.L. “High-throughput” technology, which yields enormous amounts of data on DNA sequences.These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.M. Bioinformatics, which is the use of computational tools to process a large volume of data.N. Interdisciplinary research teams “data mine” to identify and annotate genes.O. Biology can be viewed as having two dimensions: a “vertical” dimension covering the size scale from atoms to the biosphere and a “horizontal” dimension that stretches across the diversity of life.P. The latter includes organisms alive today and also ancestral forms throughout life’s history.Q. The evolutionary connections among all organisms explain the unity and diversity of life.R. Diversity is a hallmark of life.S. At present, biologists have identified and named about 1.5 million species.T. This includes over 280,000 plants, almost 50,000vertebrates, and over 750,000 insects.U. Thousands of newly identified species are added each year (AP).V. Estimates of the total diversity of life range from about 5 million to over 30 million species.II. The Three Domains of LifeA. Species that are very similar share a common ancestor that represents a relatively recentbranch point on the tree of life like how brown bears and polar bears share a recent common ancestor and both bears are also related through older common ancestors to other organisms.B. The presence of hair and milk-producing mammary glands indicates that bears are related to other mammals.C. Similarities in cellular structure, like cilia, indicate a common ancestor for all eukaryotes.D. All life is connected through evolution.E. Until the last decade, biologists divided the diversity of life into 5 kingdoms.F. New methods, including comparisons of DNA among organisms (bioinformatics), have led to a reassessment of the number and boundaries of the kingdoms and various classification schemes now include 6, 8, or more kingdoms.G. The research shows that there are three even higher levels of classifications, the Domains.H. The three domains are the Bacteria, Archaea, and Eukarya.I. Domain Bacteria and domain Archaea compose the prokaryotes; most prokaryotes are single-celled and microscopicJ. Archea are unicells that are often extremophiles but also occur in soils, marshland and the human colon…e.g. methanogens.K. Domain Eukarya includes all eukaryotic organismsL. Domain Eukarya includes three multicellular kingdoms; plants, which produce their own food by photosynthesis, fungi which absorb nutrients, and animals which ingest their food.M. Other eukaryotic organisms were formerly grouped into the Protist kingdom, though these are now often grouped into many separate groups Both Bacteria and Archaea haveprokaryotes.N. Archaea may be more closely related to eukaryotes than they are to bacteria.O. The Eukarya includes at least four kingdoms: Protista, Plantae, Fungi, and Animalia.P. The Plantae, Fungi, and Animalia are primarily multicellular.Q. Protista is primarily unicellular but includes the multicellular algae in many classification schemes.R. Most plants produce their own sugars and food by photosynthesis.S. Most fungi are decomposers that breakdown dead organisms and organic wastes.T. Animals obtain food by ingesting other organisms. U. Underlying the diversity of life is a striking unity, especially at the lower levels of organization.V. The universal genetic language of DNA unites prokaryotes, like bacteria, with eukaryotes,like humans.W. Among eukaryotes, unity is evident in many details of cell structure above the cellular level; organisms are variously adapted to their ways of life.X. This creates challenges in the ongoing task of describing and classifying biological diversity.Y. Evolution accounts for this combination of unity and diversity of life.Z. Human Ancestor “Toumai”III. Evolution BasicsA. Core theme of Biology.B. Life on earth is more than 3 billion years oldC. Evolution is evident at all hierarchical levels from communities of organisms to metabolism in cells.D. Charles Darwin is regarded as the foremost scientist in the theory of evolution.E. Voyage around the world in early 1800’s on the ship HMS “Beagle”.F. Part of his study was on the Galapagos Islands which were relatively new volcanic islandsoff the coast of equatorial S. America. G. Charles Darwin brought biology into focus in 1859when he presented two main conceptsin The Origin of Species.H. The first was that contemporary species arose from a succession of ancestors through “descent with modification” (evolution).I. The second was that the mechanism of evolution is natural selection.J. Darwin explained natural selection by connecting two observations: a. Observation 1: Individuals in a population of any species vary in many heritable traits. b. Observation 2: Any population can potentially produce far more offspring than the environment can support.K. This creates a struggle for existence among variant members of a population (PT).L. Darwin