copyright cmassengale Exploring Life copyright cmassengale

Themes Help to Organize Biological information copyright cmassengale

Unifying Themes in Biology Evolution~ biology’s core theme; differential reproductive success Emergent Properties~ hierarchy of life (new properties at each level) The Cell~ all organism’s basic structure Heritable Information~ DNA Structure & Function~ form and function (Form determines function) Environmental Interaction~ organisms are open systems Regulation~ feedback mechanisms Unity & Diversity~ universal genetic code Scientific Inquiry~ observation; testing; repeatability copyright cmassengale

copyright cmassengale Prokaryotic cell DNA (no nucleus) Eukaryotic cell Membrane Membrane Cytoplasm Figure 1.8 Contrasting eukaryotic and prokaryotic cells in size and complexity Organelles Nucleus (contains DNA) 1 µm copyright cmassengale

Life can be divided into different levels of biological organization copyright cmassengale

copyright cmassengale The biosphere Cells Organs and organ systems 10 µm Cell Ecosystems Organelles Communities 1 µm Atoms Figure 1.4 Levels of biological organization Tissues 50 µm Populations Molecules Organisms copyright cmassengale

copyright cmassengale The biosphere Ecosystems Communities Figure 1.4 Levels of biological organization Populations Organisms copyright cmassengale

copyright cmassengale Cells Organs and organ systems 10 µm Cell Organelles 1 µm Figure 1.4 Levels of biological organization Atoms Tissues 50 µm Molecules copyright cmassengale

Hierarchy of Organization Molecule Organelle Cells Tissues Organ Systems Organism copyright cmassengale

copyright cmassengale Macromolecules Carbohydrates (CHO) - energy Lipids (CHO) – long term energy Proteins (CHON) – building & work Nucleic acids (CHONP) – genetic information copyright cmassengale

Feedback Regulation: Negative Accumulation of an end product of a process slows that process Example: sugar breakdown generates ATP; excess ATP inhibits an enzyme near the beginning of the pathway copyright cmassengale

Feedback Regulation: Positive An end product speeds up its production Example: blood clotting in response to injury copyright cmassengale

copyright cmassengale The Process of Science Scientific Method Deductive reasoning “If….then” Logic Hypothesis (testable) Theory (widely tested & accepted) Law (proven) copyright cmassengale

Properties of Living Things Which is considered living? Why? Frequently, presenters must deliver material of a technical nature to an audience unfamiliar with the topic or vocabulary. The material may be complex or heavy with detail. To present technical material effectively, use the following guidelines from Dale Carnegie Training®.   Consider the amount of time available and prepare to organize your material. Narrow your topic. Divide your presentation into clear segments. Follow a logical progression. Maintain your focus throughout. Close the presentation with a summary, repetition of the key steps, or a logical conclusion. Keep your audience in mind at all times. For example, be sure data is clear and information is relevant. Keep the level of detail and vocabulary appropriate for the audience. Use visuals to support key points or steps. Keep alert to the needs of your listeners, and you will have a more receptive audience. Paramecium Bacteriophage copyright cmassengale

copyright cmassengale Early Views of Life Vitalism: The insistence that there is some big, mysterious extra ingredient in all living things Led to idea of spontaneous generation (life can come from nonliving material) Flies came from dead animals Mice came from Hay In your opening, establish the relevancy of the topic to the audience. Give a brief preview of the presentation and establish value for the listeners. Take into account your audience’s interest and expertise in the topic when choosing your vocabulary, examples, and illustrations. Focus on the importance of the topic to your audience, and you will have more attentive listeners. copyright cmassengale

copyright cmassengale The Redi Experiment Idea was challenged by scientist Francesco Redi in 1698. Designed an experiment where 3 jars contained meat. If you have several points, steps, or key ideas use multiple slides. Determine if your audience is to understand a new idea, learn a process, or receive greater depth to a familiar concept. Back up each point with adequate explanation. As appropriate, supplement your presentation with technical support data in hard copy or on disc, e-mail, or the Internet. Develop each point adequately to communicate with your audience. copyright cmassengale

copyright cmassengale Setup 1 One Jar contained meat and had an open top which would allow the passage of flies. (maggots would appear on the meat) Determine the best close for your audience and your presentation. Close with a summary; offer options; recommend a strategy; suggest a plan; set a goal. Keep your focus throughout your presentation, and you will more likely achieve your purpose. copyright cmassengale

copyright cmassengale Setup 2 The second jar was covered with an airtight lid not allowing the passage of flies. (no maggots would appear on the meat) copyright cmassengale

copyright cmassengale Setup 3 The third was covered by a screen allowing passage of eggs, but not flies. (few maggots would appear on meat) copyright cmassengale

copyright cmassengale Conclusion Since the third setup would theoretically allow the passage of “ethers”, but no maggots appeared, it was implied that flies were the source of the maggots. (Deductive Reasoning) Led to the theory of Biogenesis All life comes from preexisting life copyright cmassengale

Life is Recognized by What Living Things Do copyright cmassengale

copyright cmassengale Order Response to the environment Evolutionary adaptation Figure 1.3 Some properties of life Regulation Reproduction Energy processing Growth and development copyright cmassengale

copyright cmassengale PROPERTIES of LIFE Be made of Cells. The Cell is the basic unit of life Is self contained and possesses a barrier (membrane) which separates itself from the environment. Two types of organisms. Unicellular - One celled organism (Uni=1) Multicellular - Many cells (Multi=”many”) copyright cmassengale

copyright cmassengale Cells The cell is the lowest level of organization that can perform all activities required for life All cells: Are enclosed by a membrane Use DNA as their genetic information The ability of cells to divide is the basis of all reproduction, growth, and repair of multicellular organisms copyright cmassengale

copyright cmassengale PROPERTIES of LIFE Living Things must Reproduce. Must be able to create more of it’s own kind Two types of reproduction: Sexual - Two parent organisms combine genetic material to produce the offspring. Asexual - When a single organism can divide or “bud” to create it’s offspring without another of it’s species. copyright cmassengale

copyright cmassengale PROPERTIES of LIFE Living things ALL Have DNA. Universal Genetic Code Instructions for making all the bodies proteins Located in the nucleus (eukaryotes) or nucleiod region (prokaryotes) copyright cmassengale

copyright cmassengale DNA Chromosomes contain most of a cell’s genetic material in the form of DNA (deoxyribonucleic acid) DNA is the substance of genes Genes are the units of inheritance that transmit information from parents to offspring copyright cmassengale

copyright cmassengale Each chromosome has one long DNA molecule with hundreds or thousands of genes DNA is inherited by offspring from their parents DNA controls the development and maintenance of organisms copyright cmassengale

copyright cmassengale Sperm cell Nuclei containing DNA Fertilized egg with DNA from both parents Embryo’s cells with copies of inherited DNA Egg cell Offspring with traits inherited from both parents Figure 1.9 Inherited DNA directs development of an organism copyright cmassengale

copyright cmassengale Each DNA molecule is made up of two long chains arranged in a double helix Each link of a chain is one of four kinds of chemical building blocks called nucleotides (A,T,C,G) copyright cmassengale

(b) Single strand of DNA Nucleus DNA Nucleotide Cell Figure 1.10 DNA: The genetic material (a) DNA double helix (b) Single strand of DNA copyright cmassengale

copyright cmassengale Genes control protein production indirectly DNA is transcribed into RNA then translated into a protein An organism’s genome is its entire set of genetic instructions copyright cmassengale

copyright cmassengale PROPERTIES of LIFE Living things must Grow & Develop. Growth refers to two processes. Increase in the number of cells. Increase in the size of cells. Development refers to changes in the organism which occur through it’s life-span. Includes cell differentiation. Includes organ development Includes aging & death. copyright cmassengale

copyright cmassengale PROPERTIES of LIFE Living things obtain & use energy. Energy is used by all living things for growth, development & reproduction. Life processes which result in “building” the organism ia known as Anabolism. (endergonic-store energy) Life process where energy is extracted by “breaking-down” substances is called Catabolism. (exergonic-release energy) ATP – cellular energy copyright cmassengale

copyright cmassengale PROPERTIES of LIFE Living things must Respond (or react) to their environment in some way. Something which causes an organism to react is known as a Stimulus (stimuli). The ability of an organism to react is called Irritability. Most responses are geared for maintaining Homeostasis. Homeostasis is a process where an organism maintains a stable internal environment so life can continue. Some examples include temperature, pH, and water content of the cell. copyright cmassengale

Organisms Interact with Their Environments Every organism interacts with its environment, including nonliving factors and other organisms Both organisms and their environments are affected by the interactions between them For example, a tree takes up water and minerals from the soil and carbon dioxide from the air; the tree releases oxygen to the air and roots help form soil copyright cmassengale

copyright cmassengale Ecosystem Dynamics The dynamics of an ecosystem include two major processes: Cycling of nutrients, in which materials acquired by plants eventually return to the soil (Carbon, Phosphorus, Water, Nitrogen) The flow of energy from sunlight to producers to consumers copyright cmassengale

(plants and other photosynthetic Sunlight Ecosystem Producers (plants and other photosynthetic organisms) Cycling of chemical nutrients Heat Chemical energy Figure 1.5 Nutrient cycling and energy flow in an ecosystem Consumers (such as animals) Heat copyright cmassengale

copyright cmassengale Evolution unifies biology at different scales of size throughout the history of life on Earth copyright cmassengale

copyright cmassengale Diversity of Life Approximately 1.8 million species have been identified and named to date, and thousands more are identified each year Estimates of the total number of species that actually exist range from 10 million to over 100 million copyright cmassengale

copyright cmassengale Grouping Species Taxonomy is the branch of biology that names and classifies species into groups of increasing breadth Domains, followed by kingdoms, are the broadest units of classification copyright cmassengale

copyright cmassengale Species Genus Family Order Class Phylum Kingdom Domain Ursus americanus (American black bear) Ursus Ursidae Carnivora Mammalia Chordata Figure 1.14 Classifying life Animalia Eukarya copyright cmassengale

The Three Domains of Life The three-domain system is currently used, and replaces the old five-kingdom system Domain Bacteria and domain Archaea comprise the prokaryotes Domain Eukarya includes all eukaryotic organisms copyright cmassengale

copyright cmassengale (a) DOMAIN BACTERIA (b) DOMAIN ARCHAEA (c) DOMAIN EUKARYA Figure 1.15 The three domains of life Protists Kingdom Plantae Kingdom Fungi copyright cmassengale Kingdom Animalia

copyright cmassengale Figure 1.15 The three domains of life DOMAIN BACTERIA copyright cmassengale

copyright cmassengale Figure 1.15 The three domains of life DOMAIN ARCHAEA copyright cmassengale

copyright cmassengale Eukarya The domain Eukarya includes four kingdoms: Protista (unicellular) Fungi (mostly multicellular) Plantae (multicellular) Animalia (multicellular) copyright cmassengale

copyright cmassengale Protists Kingdom Plantae Figure 1.15 The three domains of life Kingdom Fungi (c) DOMAIN EUKARYA Kingdom Animalia copyright cmassengale

copyright cmassengale Figure 1.15 The three domains of life Protists copyright cmassengale

copyright cmassengale Figure 1.15 The three domains of life Kingdom Fungi copyright cmassengale

copyright cmassengale Figure 1.15 The three domains of life Kingdom Plantae copyright cmassengale

copyright cmassengale Figure 1.15 The three domains of life Kingdom Animalia copyright cmassengale

copyright cmassengale Fossils and other evidence document the evolution of life on Earth over billions of years copyright cmassengale

copyright cmassengale Figure 1.17 Digging into the past copyright cmassengale

copyright cmassengale Natural Selection Charles Darwin published On the Origin of Species by Means of Natural Selection in 1859 Darwin made two main points: Species showed evidence of “descent with modification” from common ancestors Natural selection is the mechanism behind “descent with modification” Darwin’s theory explained the duality of unity and diversity copyright cmassengale

copyright cmassengale Figure 1.18 Charles Darwin as a young man copyright cmassengale

Descent with Modifications Fig 1.19 Unity and diversity in the orchid family copyright cmassengale

copyright cmassengale Darwin observed that: Individuals in a population have traits that vary Many of these traits are heritable (passed from parents to offspring) More offspring are produced than survive Competition is inevitable Species generally suit their environment copyright cmassengale

copyright cmassengale Darwin inferred that: Individuals that are best suited to their environment are more likely to survive and reproduce Over time, more individuals in a population will have the advantageous traits In other words, the natural environment “selects” for beneficial traits copyright cmassengale

copyright cmassengale 1 Population with varied inherited traits. 2 Elimination of individuals with certain traits. 3 Reproduction of survivors. 4 Increasing frequency of traits that enhance survival and reproductive success. Figure 1.20 Natural selection copyright cmassengale

copyright cmassengale Natural selection is often evident in adaptations of organisms to their way of life and environment Bat wings are an example of adaptation copyright cmassengale

copyright cmassengale The Tree of Life “Unity in diversity” arises from “descent with modification” For example, the forelimb of the bat, human, horse and the whale flipper all share a common skeletal architecture Fossils provide additional evidence of anatomical unity from descent with modification copyright cmassengale

copyright cmassengale Darwin proposed that natural selection could cause an ancestral species to give rise to two or more descendent species For example, the finch species of the Galápagos Islands Evolutionary relationships are often illustrated with tree-like diagrams that show ancestors and their descendents copyright cmassengale

Cactus-flower-eaters Green warbler finch Certhidea olivacea Warbler finches Insect-eaters COMMON ANCESTOR Gray warbler finch Certhidea fusca Seed-eater Sharp-beaked ground finch Geospiza difficilis Bud-eater Vegetarian finch Platyspiza crassirostris Mangrove finch Cactospiza heliobates Woodpecker finch Cactospiza pallida Tree finches Insect-eaters Medium tree finch Camarhynchus pauper Large tree finch Camarhynchus psittacula Small tree finch Camarhynchus parvulus Large cactus ground finch Geospiza conirostris Figure 1.22 Descent with modification: adaptive radiation of finches on the Galápagos Islands Cactus-flower-eaters Cactus ground finch Geospiza scandens Ground finches Seed-eaters Small ground finch Geospiza fuliginosa Medium ground finch Geospiza fortis Large ground finch Geospiza magnirostris copyright cmassengale

copyright cmassengale