Introduction to Zoology & Classification

SCIENTIFIC WORDS / IDEAS

Scientific Terminology Hypothesis: A prediction of the outcome of an experiment Written: If______________, then _____________, because____________.

Testing Hypotheses Observation Experiment Something you take in with your senses Experiment Perform CONTROLLED experiments to test repeated observations If continued to be accepted………….

Scientific Theory Principle Tested many times Explains many different phenomena Makes predictions Falsifiable – people are constantly trying to prove wrong and correct “bad”’ science

Theory vrs Scientific Theory Theory (as used outside of science) Guess Speculation Has not been tested

Law vrs Theory Law Theory Observation that has been repeated numerous times Law of gravity Does not explain the observation Theory Explains why or how something in nature happens

Which is most important to a scientist? Fact Hypothesis Law Theory

Theory is the most important Explains laws, hypotheses and facts Law States what happens Hypothesis Untested theory Fact Observation

Major Scientific Theories Germ Theory of Disease Germs cause infectious disease Atomic Theory Matter is made if tiny atoms Gene Theory (Chromosomal Theory) Genes on chromosomes determine heredity Cell Theory All living things are made of cells

Theory of Evolution Populations of organisms change over time Changes result in new species that share a common ancestor.

Evolution is both a fact and a theory Evolution is documented in the fossil record and has been observed in our lifetime. Theory How evolution happens

Theory of Evolution Scientists no longer ask if evolution occurs. They study how evolution occurs. Evolution is the major theory that guides research in Zoology

CLASSIFICATION REVIEW

Aristotle 384 BC Classified organisms as either plants or animals

Carolus Linnaeus 1707-1778 Swedish Botanist Systema Naturae, 10ed 1758 Classification system Taxonomic groups of related organisms Binomial nomenclature two names Genus + species Capitalized, Italics

Taxonomic Groups

Species “Species are groups of actually or potentially interbreeding populations, which are reproductively isolated from other such groups.” When they reproduce, create FERTILE offspring Ernst Mayr

* * Archaea

Classification of Living Things DOMAIN Bacteria Archaea Eukarya KINGDOM Eubacteria Archaebacteria Protista Fungi Plantae Animalia CELL TYPE Prokaryote Eukaryote CELL STRUCTURES Cell walls with peptidoglycan Cell walls without peptidoglycan Cell walls of cellulose in some; some have chloroplasts Cell walls of chitin Cell walls of cellulose; chloroplasts No cell walls or chloroplasts NUMBER OF CELLS Unicellular Most unicellular; some colonial; some multicellular Most multicellular; some unicellular Multicellular MODE OF NUTRITION Autotroph or heterotroph Heterotroph Autotroph EXAMPLES Streptococcus, Escherichia coli Methanogens, halophiles Amoeba, Paramecium, slime molds, giant kelp Mushrooms, yeasts Mosses, ferns, flowering plants Sponges, worms, insects, fishes, mammals

Kingdom Monera or Eubacteria Single celled Prokaryotic Make or absorb food Cell wall peptidoglycan

Kingdom Archaea Single celled Prokaryotic Make or absorb food DNA Similar to Eukaryotic Cell wall Pseudopeptidoglycan or protein only

Kingdom Protista Single celled Eukaryotic Ingest or produce food Kind of the “junk drawer” of classification

Kingdom Fungi Multicellular Eukaryotic Cell wall Chitin Absorb food

Kingdom Plantae Multicellular Eukaryotic Cell wall Produce food Cellulose Produce food photosynthesis

Kingdom Animalia Multicellular Eukaryotic No cell wall Ingest food Motile

Terminology Classification Taxonomy Systematics Assigning organisms to different catagories based on their relationship Taxonomy The science of naming organisms Systematics Determining evolutionary relationships of organisms

Cladogram Evolutionary relationship of a group of organisms Each clad (group) share something in common Ancestral traits are the oldest Derived traits evolved later Nested hierarchially

Cladogram for Transportation Wheels are the most ancestral Wings are the most derived

MAKE A CLADOGRAM

Characteristics for Constructing Cladogram Tail is the most ancestral Four limbs is the oldest derived trait Fur is a later derived trait Loss of tail is the most derived trait

Gorilla Chimpanzee Tiger Lizard Fish Tail Lost Fur Four Limbs

Synapomorphy A derived character shared by two or more groups. Fur is a synapomorphy for the various groups of mammals. Synapomorphies are used to determine evolutionary relationships

Symplesiomorphy Character shared by a number of groups Inherited from ancestors older than the last common ancestor. Symplesiomorphies are not helpful in determining evolutionary relationships

Accepted Cladogram for Animals Birds Mammals Reptile Amphibian Fish Four Limbs Amniotic Egg Endothermic Fur Feathers Vertebrae

Homologous Characters Similarity in features of different groups because of their descent from a common ancestor

Analagous Characters Similarity in characteristics in different groups caused by factors OTHER THAN their distant common ancestry

Monophyletic A group of all the descendants of a common ancestor The common ancestor is in the group Example: Mammalia Ancestor was a mammal like reptile

Paraphyletic A group of descendants of a common ancestor Common ancestor is in the group Not all descendants are included Example: Reptiles Does not include birds and mammals

Polyphyletic A group that has some similarities Common ancestor is in not in the group Not all descendants are included Example: Flying vertebrates

Asymmetry No Lines of symmetry Most protists & many sponges Do not develop complex communication, sensory or locomotor function

Radial Symmetry Multiple lines of symmetry Not as simple communication, sensory or locomotor function; but still not as complex

Bilateral Symmetry One line of symmetry Usually longitudinal, dividing animals into right and left mirror images Characteristic of active, motile, crawling or swimming animals Usually move in one direction – so the end that faces the world is normally where complex sensory, nervous and feeding structures evolve and develop. (Cephalization)