The core themes of biology are presented in this unit These include 1 evolution 2 hierarchy levels of organization 3 relationships between structure and function 4 scientific method science as a way of knowing and 5 the characteristics of life Taxonomy provides a means of scientifically organizing living things so that they may be analyzed and studied Taxonomy Purpose and History Taxonomy the science of classification Aristotle first taxonomic system Plants trees shrubs and herbs Animals air dwellers water dwellers land dwellers System flawed because scientifically valid characteristics by modern standards were often not used in determining the categories Carolus Linnaeus father of modern taxonomy Eliminated use of common names Used Latin as a basis for nomenclature Created binomial nomenclature identifying each organism by their Genus and species ex Homo sapiens in which Homo is the genus and sapiens is the species Created other taxa for classification purposes kingdom phylum class order family genus species Used morphological characteristics as a basis for classification The Linnaean system of classification is still in use today Linnaeus was devoutly religious but his taxonomic system was later to be used to demonstrate the phylogenetic evolutionary relationships among living organisms Linnaeus Latinized his own name from Carl Line Five major kingdoms of life are currently recognized Five Kingdoms of Life 1 Cell type A Prokaryotic P primitive lack membrane bound internal organelles B Eukaryotic E true nucleus membrane bound organelles 2 Cells Unicellular U Colonial C Multicellular M 3 Nutrition A Autotrophic A Source of carbon is simple such as carbon dioxide CO2 B Heterotrophic H Source of carbon is complex such as carbohydrates proteins lipids or nucleic acids Kingdom Organisms Cell Type Cells Nutrition 1 Monera Bacteria P U H Blue green bacteria U C A 2 Protista Protozoa E U H Algae U C A Seaweeds M A 3 Fungi Mushrooms E M all H Mildews Yeasts U 4 Plantae Mosses E M all A Liverworts Ferns Gymnosperms Conifers Angiosperms Flowering plants 5 Animalia Sponges E M all H Cnidaria Jellyfish Worms Arthropods Insects crustaceans Mollusca Clams squid Echinoderms Sea star sand dollar Chordate Fish amphibians reptiles birds mammals Common Threads that Connect All Life Life is diverse but there are common themes that all living things exhibit 1 Evolution is the core theme of biology Evolution the process by which life on earth has changed over time Natural Selection the theory proposed by Charles Darwin to explain how evolution has occurred 1859 On the Origin of Species by Natural Selection Natural selection emphasizes the variation that exists within and between species the competition that occurs because of limited resources and differential rates of survival and reproduction which result from this competition The fossil record documents the evolution of species 2 Science is an active process for understanding life Scientific method processes by which scientists conduct investigations There is no one scientific method Scientists actually use a variety of techniques to learn more about the world around us However many experimental studies would recognize the following steps A Statement of the problem B Hypothesis formation An educated guess C Experiment 1 experimental group 2 control group D Collection of data E Analysis of results F Conclusion Reject or accept the hypothesis G Communication of findings Considerations pertaining to the scientific method A Hypothesis must be testable B Sample size must be sufficiently large C Experiment must have proper controls D Experiment must be reproducible 3 Life is organized at different levels chemical cellular tissues organs organ systems organisms population community ecosystem biome biosphere 4 At every level of life s hierarchy the whole is greater than the sum of its parts Emergent properties special features or properties that result from a system s particular organization do not exist without the organization Emergent Properties that Define Life A organisms are highly structured lower entropy B organisms can take in transform and use energy C organisms respond to stimuli D organisms grow and develop E organisms reproduce F organisms evolve 5 Life s properties have a chemical basis Living things are composed of inorganic and organic substances Important inorganic substances water minerals salts Important organic substances carbohydrates proteins lipids nucleic acids ex protein keratin hair feathers scales DNA genetic information Gregor Mendel Genetics James Watson and Francis Crick DNA 6 All organisms are composed of cells 1838 1839 Schleiden and Schwann develop the cell theory All living things are composed of cells They may be unicellular colonial or multicellular and they may be prokaryotic or eukaryotic cells 7 All organisms demonstrate close connections between form anatomy and function physiology ex dentition herbivores omnivores carnivores plants flower form related to pollination 8 Organisms interact with their environments ecology the branch of biology dealing with the relationships between organisms and their environments photosynthesis and respiration Energy flows through ecosystems while nutrients cycle food webs interconnected feeding relationships within ecosystems Biology is connected to our lives in many ways Global warming Endangered species Genetic engineering Medical problems AIDS Ebola Biology offers a deeper understanding of life on earth and offers solutions to problems that confront us CHEMICAL BASIS OF LIFE Many biological processes can only be understood by studying them at the chemical level Biochemical processes are essential to life on earth ex photosynthesis cellular respiration matter anything that occupies space and has mass matter is composed of various combinations of elements element a substance that cannot be broken down to other substances by ordinary chemical means 92 elements occur in nature others have been synthesized in labs About 25 of these elements are essential to life Carbon C Hydrogen H Oxygen O and Nitrogen N make up about 96 of any living organism The remaining 4 is made primarily of Calcium Ca Potassium K Phosphorus P and Sulfur S Importance of Various Elements Carbon found in all organic molecules Hydrogen also found in all organic molecules water Oxygen aerobic respiration oxidation reactions water Nitrogen constituent of amino acids nucleic acids Calcium necessary for bone formation
View Full Document
Unlocking...