BIOL 113: Introduction to Biology PDF

Overview of course There are between approximately 10 to 400 million species of living organisms on Earth! We will cover the evolution and organismal biology The History of Life The Scientific Method Evolution Systematics Diversity Ecology  Biology Exploring Life The leopard is...

Overview of course There are between approximately 10 to 400 million species of living organisms on Earth! We will cover the evolution and organismal biology The History of Life The Scientific Method Evolution Systematics Diversity Ecology  Biology Exploring Life The leopard is an excellent example of an organism adapted to its environment It survives because of adaptations to its environment. –Examples are coat camouflage, hunting and climbing ability Adaptations are the result of evolution –Evolution is the process of change that transforms life Biology is the scientific study of life  Biosphere Life’s levels of organization define Ecosystem Florida coast the scope of biology – Life emerges through Community All organisms on organization the Florida coast of various Population Group of brown pelicans levels Organism Brown pelican – What is the Spinal cord Organ system smallest Nervous system unit/level do Nerve Brain Organ Brain we consider Tissue Nervous tissue to be alive? Cell Nucleus Atom Nerve cell Organelle Nucleus Molecule DNA Life is studied at different levels of organization. The biosphere is defined as the entire surface of the Earth, including living and nonliving components The biosphere is composed of biomes Biomes are composed ecosystems  snake, pronghorn, hawk, bushes, grass, rocks, stream Ecosystem = all of the organisms living in a particular area, plus non-living physical components –e.g., Cypress swamp Cypress swamp Cypress & other trees, shrubs, duckweed, etc. Birds, mammals, reptiles, amphibians, fish, invertebrates such as crawfish, etc. Water, soil (mud), sunlight, etc.  Community = –e.g., Cypress swamp ecosystem includes communities of birds Herons, egrets, ospreys, hawks, eagles, owls – They interact with each other sometimes compete for food & nesting spots, etc. Population = –e.g., The egrets nesting at Lake Martin, LA are a population of birds  Organism = an individual living thing – e.g., Each of you is an organism – A single tree is an organism – An individual bacterium is an organism pronghorn Species = Populations of organisms that can interbreed Pronghorn population  Organ System = group of organs that function together – e.g., Nervous system includes sensory and motor components the nervous system Organ = structure in the body that is composed of several tissues & has a particular function – e.g., the heart pumps blood around the body – The brain processes sensory information the brain Tissue = group of similar cells w/ similar functions – nervous tissue (e.g. neurons), epithelial tissue (e.g. lines the digestive tract)  Cell = unit of living material separated by a membrane & containing organelles – e.g., nerve cells transmit & coordinate information Organelle = a membrane bound structure that performs a specific function Organelles: mitochondrion chloroplast nucleus Molecule = cluster of atoms arranged in a particular way for a particular function – e.g., DNA is a hereditary molecule DNA water glucose Atom = Smallest particle of an element that retains the properties of that element hydrogen carbon nitrogen oxygen Subatomic particles proton Neutron Electron (protons, neutrons, electrons) – Make up atoms Living organisms Sunlight interact with their Ecosystem environments, exchanging matter and energy Producers To be successful, an Cycling (such as plants) Heat ecosystem must of chemical accomplish two things nutrients Chemical energy Recycle chemicals necessary for life Move energy Consumers (such as animals) through the Heat ecosystem – Energy enters as light and exits as heat How does energy flow through communities? Energy enters communities through photosynthesis and is passed from one trophic level to another 1.Most of the electromagnetic rays that reach earth are reflected. About 1% will reach the surface of that 1% about 3% will be trapped by primary producers. Life exists on 0.03% of the sun’s energy 2.Plants, plankton, algae, and some bacteria are primary producers. They are called autotrophs (Greek = self feeder). This means they can produce food through photosynthesis 3. Consumers eat primary producers and other animals to get energy. These organisms are heterotrophs (Greek = other feeder). A heterotrophic organism by definition can consume other organisms that fall into one of the three following categories: autotrophs, heterotrophs or both autotrophs and heterotrophs  Cells are the structural and functional units of life Two distinct groups of cells exist Prokaryotic cells – Simple and small – Bacteria are prokaryotic Eukaryotic cells – Possess organelles separated by membranes Why is a cell considered to be the – Plants, animals, and basic unit of life? fungi are eukaryotic Fundamental properties of life The unity of life: All forms of life have common features Seven Characteristics of Life 1. Order Living things are both complex and composed of cells. Cell theory is composed of three principles – All living organisms are made of cells – All cells come from other cells – Cells are the basic unit of life  Seven Characteristics of Life (cont.) 2. Regulation and homeostasis Regulation to maintain stable internal conditions 3. Growth and development Cells produce larger and more cells and in some multicellular organisms cells differentiate and are specialized for specific functions. 4. Energy use and metabolism Organisms require the energy to maintain their internal order. The collective chemical reactions that occur in a organism are its metabolism. Some organisms are able to generate their own energy while others must get their energy from other sources.  Seven Characteristics of Life (cont.) 5. Response to the environment Response to stimuli, and adjustments (short- and long- term changes) 6. Reproduction (all-genetic the generation of offspring) In sexual reproduction a combination of genetic material (DNA) from both parents are passed to the offspring. In asexual reproduction the all-genetic information from the sole parent is passed to the offspring. 7. Evolutionary adaptation Populations evolve over many generations - Some are more successful at survival and reproduction. - Surviving populations of organisms result in being better adapted to their environment.  Seven Characteristics of Life (cont.) (1) Order (2) Regulation (3) Growth and development (4) Energy processing (5) Response to the environment (6) Reproduction (7) Evolutionary adaptation  The function and structure of an organism is based on DNA DNA is the genetic (hereditary) material of all Cell DNA Nucleotide cells A gene is a discrete unit of DNA The chemical structure of DNA accounts for Nucleus its function The diversity of life results from differences in DNA structure from (a) DNA double helix (b) Single strand of DNA individual to individual The diversity of life can be arranged into three domains There are nearly two million species that have been identified The branch of biology called Taxonomy arranges species, such as Homo sapiens, into a hierarchy "Kind professors cannot often fail good students" to remember categories Domain–most inclusive; species–least inclusive The diversity of life can be arranged into three domains The three domains (groups) of life Bacteria - prokaryotic, and most are unicellular and microscopic (the most diverse and widespread of the prokaryotes) Archaea - like bacteria, are prokaryotic, and most are unicellular and microscopic (many live in extreme environments of great heat, pressure, salinity, etc.) Eukarya - are eukaryotic and contain a nucleus and organelles Classification of Life 1969–Roger Whittaker– five-kingdom system – Monera, Protista, Fungi, Plantae, Animalia Recent proposal–Carl Woese-1990-three-domain system – Bacteria, Archaea, Eukarya – Discovered that kingdom Monera included two very distinct groups (Bacteria and Archaea) based on nucleotide sequences of ribosomal RNA  Domain Eukarya Domain Bacteria Bacteria (multiple kingdoms) Protists (multiple kingdoms) Kingdom Plantae Domain Archaea Archaea (multiple kingdoms) Kingdom Fungi Kingdom Animalia  Kingdom Protista (About 250,000 species) Most unicellular but some are colonial or simple multicellular Some photosynthesize while others are heterotrophic and eat bacterial or other protists Most live in aquatic habitats Some mobile and some sessile In many cases if an organism did not fit into one of the three other kingdoms of eukaryotes it was placed in Protista unicellular unicellular multicellular  Kingdom Plantae (about 300,000 species) Multicellular Almost all capable of photosynthesis Bryophytes, ferns, gymnosperms, flowering plants (angiosperms) Cell wall made primarily of cellulose All sessile  Kingdom Fungi (about 100,000 species) Heterotrophic Present worldwide in aquatic and terrestrial environments Many symbiotic with plants Cell walls contain chitin Most multicellular Mass of hyphae combine to make mycelium and mycelium makes up the fruiting body Sessile  Kingdom Animalia (over 1 million species) Multicellular and eat others for food – Sponges, worms, insects, mollusks, fish, amphibians, birds, reptiles, mammals Most ingest food and digest it in an internal cavity Bodies composed of cells organized into tissues (except sponges) Most capable of complex and rapid movement Nervous system Lack a rigid cell wall  Evolution explains the unity and diversity of life One of the most important works in evolution was written by Charles Darwin a British Naturalist In 1859, this published work, namely On the Origin of Species by Means of Natural Selection presented two very important ideas 1. Evidence to support the idea of evolution Descent with modification - species living today are descendants of ancestral species 2. A proposed a mechanism for evolution called natural selection Darwin’s ideas were most influenced by Charles Darwin his own observations of species he encountered Natural selection was inferred by connecting two main observations 1. Individual variation. Individuals within a population inherit different characteristics and vary from other individuals 2. Overproduction of offspring. A particular population of individuals produces more offspring than will survive to produce offspring of their own Yarrow Natural selection can be thought of as an editing mechanism – Natural selection Culls out those individuals less likely to survive and Rr Rr Rr Survivors can reproduce – Leads to adaptation As a consequence a population’s characteristics change in e.g. response to the Rr pathogen rr environment R Over time this results in R the emergence of a new species rr Here is an example of natural selection occuring What is happening to this population? 1 Population with varied inherited traits Why is this particular shift occurring? 2 Elimination of individuals with certain traits If there was no shift in the structure of population and the finch was still a predator what might that suggest? 3 Reproduction of survivors Evolutionary adaptation Pangolin (E. Africa) Cacti (N. America) Studying life requires the Scientific Method Scientists use two main approaches to learn about nature Two approaches are used to understand natural causes for natural phenomena – Discovery science - uses verifiable observations and measurements to describe science at different levels – Hypothesis-based science - uses the data from discovery science to explain science o This requires proposing and testing of hypotheses Discovery science e.g. Taxonomy Genetic divergence Plants are much larger in size that previously reported for the supposed species Hypothesis-based science There is a difference between a theory and a hypothesis – A hypothesis is a proposed explanation (an educated guess) for a set of observations e.g. The fire blight is compromising many of the Cleveland pear trees in Slippery Rock Borough. – A theory is supported by a large and usually growing body of evidence e.g. theory of evolution  What is the scientific method? The process of examination and scientific discovery that includes specific discrete steps  With hypothesis-based science, we pose and test hypotheses We solve everyday problems by using hypotheses – An example would be the reasoning we use to answer the question, “Why doesn’t the flashlight work?” – Using deductive reasoning we realize that the problem is either the (1) bulb or (2) batteries. o The hypothesis must be testable o The hypothesis must be falsifiable An example of hypothesis-based Observations science Question Hypothesis #1: Hypothesis #2: Dead batteries Burned-out bulb Prediction: Prediction: Replacing batteries Replacing bulb will fix problem will fix problem Test prediction Test prediction Test falsifies hypothesis Test does not falsify hypothesis 1. Observation The leaves on maple trees fall in autumn when the days get colder and shorter 2. Question (?) 3. Hypothesis The shorter daylight causes maples to drop their leaves. 4. Experimentation Small maple trees are grown in two small green houses where the only variable is the length of light. What is the difference between a control group and an experimental group ? Looking at the data, what would you say about the hypothesis ? Another hypothesis: Mimicry (anti-predation strategy) Protects the nonpoisonous king snakes from predators in areas inhabited by the poisonous coral snake. – The hypothesis predicts that predators learn to avoid the warning coloration of coral snakes Eastern coral snake (poisonous) Scarlet king snake (nonpoisonous)  Experimentation – The experiment has a control group using brown artificial snakes for comparison – The experimental group is artificial snakes with the red, black, and yellow ring pattern of king snakes King snake pattern Brown snake pattern  Results of mimicry experiment 100 Artificial 83% 84% king snakes Percent of total attacks 80 on artificial snakes Artificial brown snakes 60 40 20 17% 16% 0 Coral snakes Coral snakes absent present