Bios 101 PM Biology of Populations and CommunitiesWhat is Out There?Biology is the study of life, but what is life?processes that define a living thingOrganization and InformationHomeostasisInformationDNANeed for and Energy SourceHumans are HeterotrophsReproduction and EvolutionOn Earth, types of living things fall into (more or less) discrete categories called “species”Slide 13How Many Species are Out There?Slide 15Slide 16Slide 17Slide 18Slide 19The Old ClassificationThe “Tree Within a Tree” PhenomenonNew ideas on the tree of lifeSlide 23Some Highlights in the Tree of LifeProkaryotesBacteriaProteobacteriaSlide 28Slide 29SpirochetesArchaeaSlide 32EukaryotesSlide 34Some Kingdoms of Eukarya“Protists”FungiSlide 38ViridiplantaeTrue PlantsAnimalsSlide 42BiodiversitySlide 44Ecology and EvolutionExample: Pollination Syndromes in FlowersSlide 47Slide 48Slide 49Slide 50Slide 51Slide 52Bios 101 PMBiology of Populations and Communities•Dr. Alan Molumby•[email protected]•6-2994•3084 SEL•Office Hours MF 9, W at 11, or by appointmentWhat is Out There?Reading: Freeman Chps. 1, 50 and 55Biology is the study of life, but what is life?processes that define a living thing•Organization and Information•Need for an Energy Source•Reproduction and EvolutionOrganization and Information•Living things are born and living things die. Although true by definition, this underlies an essential property-they are organized. •So long as an organism maintains a given level of organization, it is alive. When this organization breaks down, it dies. •Living things impose organization on nonliving matter by growth, development, and reproduction. •In death and decomposition, this organization breaks down.Homeostasis•A critical aspect of life's organization is a constant internal environment, called homeostasis, which makes the complex biochemical machinery of life possible.Information•Living things use a template to impose order on nonliving things and to maintain order within their own bodies.•In all present-day living things, this template is DNA (many viruses use RNA, but are they living?.)•This template makes proteins, which are responsible for our structure, function, and metabolism-it is copied every time living things reproduce.DNA•DNA is the prime substance of life itself (on this planet, at least), it is as close to the basis of life as we can get.•DNA is the information template for life on earth. Without DNA, living organisms could not reproduce or function.Need for and Energy Source•All living things require constant input of energy to survive. •This is because life exists in a state of dynamic equilibrium. • A dynamic equilibrium is an organized system that requires a constant input of energy to maintain itself. •Without input of energy, the organization breaks down and death is imminent.Humans are Heterotrophs•Humans, like other animals, are heterotrophs. We process energy that was originally captured by other living things.•Unlike plants, we cannot fix energy from sunlight, nor can we fix energy by reducing hydrogen sulfide these organisms are autotrophs and chemoautotrophs respectively.)•All of the energy we use to survive, and most of the nutrients, were taken from another organism.Reproduction and Evolution•All living things are able to make copies of themselves. –It is in this area that the ambiguous nature of viruses becomes apparent. A virus alone is inert. It does not use energy and cannot reproduce. In the presence of the right living cells, however, viruses can direct the production of million copies of themselves.On Earth, types of living things fall into (more or less) discrete categories called “species”•The definition of a species, and our reasons for defining it that way, will come up several times during this course.•Basically, species are groups of organisms that•1-can interbreed and produce fertile offspring and/or•2-share a set of traits in common that distinguishes them from other such groups and•3-is an evolutionary lineage that persists, ancestor to descendant, over timeQuestion: Which of the following are inherent properties of living things?A) InformationB) Sexual ReproductionC) Need for an Energy SourceD) RespirationE) A and CHow Many Species are Out There?•There are approximately 2 million described species on Earth, estimates of the true number range from 5 to 30 million, with the number ranging as high as 100 million if prokaryote “species” are recognized.•So, most of what is out there remains undescribed.•The process of describing a species is time-consuming, and demands special skills which are in short supply.–There is no central database of species, though several projects are underway to change this. –There is also an attempt to create a central database of phylogenetic information.•There are difficulties with the species concept; cryptic species, species named more than once, and polymorphic species–As a result, only a small fraction of species are named and described, some existing species have been named several times.•Some taxa are known much better than others. –For example, birds, mammals, flowering plants, and butterflies are well known,.–Most species in these groups have been described and named.•Most insect groups, such as the chalcidoids and beetles, are less well-known, but becoming much better-understood. –Only a fraction of the insects have a name and a description.•For some groups, including most microorganisms, we are only beginning to comprehend their true diversity.Above is a chalcidoid, named and described,Below are microbes from a Greenland glacier, no formal description yet•Group No. of described species •Prokaryotes 4,760 •Fungi 46,983 •Algae 26,900 •Bryophytes 17,000 •Gymnosperms 750 •Angiosperms 250,000 •Protozoans 30,800 •Sponges 5,000 •Corals and jellyfish 9,000 •Roundworms and earthworms 24,000 •Crustaceans 38,000 •Insects 751,000 •Other arthropods and minor invertebrates 132,461 •Mollusks 50,000 •Echinoderms 6,100 •Fishes (teleosts) 19,056 •Amphibians 4,184 •Reptiles 6,300 •Birds 9,198 •Mammals 4,170 •Total species 1,435,662 This is whatwe have describedso far, note the large number of insectsFrom E.O Wilson’s BiodiversityThis figure is fairly old, the numbers of described speciesIn each group have increased, but the proportions have remained fairly