EVIDENCE TO SUPPORT EVOLUTIONARY THEORY

Like pieces of a puzzle fossils enable us to develop a picture of the past THE FOSSIL RECORD Archaeopteryx ‘Ancient wing’

 Word origin: Latin fossilis means “obtained by digging”  Preserved remains or traces of animals, plants, and other types of organisms  Formed in 6 ways Unaltered Preservation :insects or plant parts trapped in amber, frozen in ice, or submerged in bogs or tar Petrification : rock-like minerals seep in slowly and replace the original organic tissues with silica, calcite or pyrite, forming a rock-like fossil - can preserve hard and soft parts - most bone and wood fossils Replacement : An organism's hard parts dissolve and are replaced by other minerals, like calcite, silica, pyrite, or iron Carbonization: only the carbon remains in the specimen - other elements, like hydrogen, oxygen, and nitrogen are removed Recrystallization : hard parts either revert to more stable minerals or small crystals turn into larger crystals Authigenic Preservation: molds and casts of organisms that have been destroyed or dissolved

Unaltered Preservation Petrification Replacement Carbonization RecrystallizationAuthigenic Preservation Mold Cast Unaltered Preservation

 Majority of fossils are formed, and found, in sedimentary rock. Why?  The constant shifting of the earths crust, together with the processes of erosion and weathering, gradually expose the fossils HOW FOSSILS ARE FORMED No heat, pressure or chemical changes in the rock that would destroy any organic remains

Relative Dating Fossils are dated ‘relative’ to their position of other fossils, either above or below them, in the layers of rock Absolute Dating Fossils are dated using radioactive decay analysis of carbon which decays at its own rate, unaffected by external physical conditions. By measuring the amount of original and transformed carbon atoms in an object, scientists can determine the age of that object. HOW FOSSIL AGE IS DETERMINED

 Basic principle of geology.  Younger strata, or layers, are deposited on top of older strata  Farther down you are the farther back in time you go… LAW OF SUPERPOSITION

 Illustrates decent with modification aspect of the theory  Current species appear to be descended from former species  Process of natural selection determines which variations survive and which become extinct FOSSIL RECORD AND EVOLUTIONARY THEORY

and vary little over time Of change -Transitional links may not be found -Transitional links should be found RATES OF EVOLUTIONARY CHANGE

DNA codes structural and functional proteins that can be traced in all organisms GENETIC EVIDENCE

Understanding how natural selection leads to evolutionary change begins with morphology  Branch of biology that deals with the form and structure of organisms and their origins  Organisms having similar morphologies, can be unrelated genetically; different morphologies can be closely related genetically  All structures are controlled by the genes of the organism, however, morphological similarities or differences can be altered by natural selection MORPHOLOGY

 All vertebrate embryos follow a common developmental plan due a set of genes that gives the same instructions for development.  These homeobox, or hox genes, define basic body plan and orientation of structures. Ex: head-tail, bilateral symmetry, eye position.  These same hox genes are found in all vertebrates and illustrates their common ancestry  As they grow, the differences that will distinguish the embryos as adults become more and more apparent as structures differentiate genetically EMBRYOLOGICAL COMPARISONS Can you identify these vertebrate embryos? chicken, cow, fish, hog, human, turtle, rabbit, salamander,

 Structures that are shared, or similar, between organisms due to common ancestry.  The more closely the organisms are related genetically, the more similar their structures.  Differences in homologous structures illustrate divergent evolution and can result in speciation  As a result of divergence similar organisms can end up looking very different as selection pressures place different demands upon survival HOMOLOGOUS STRUCTURES

 Structures similar in function or appearance but not ancestral origins  Structures develop due to similar selection demands in the environment, not, due to similar genetics  Illustrate convergent evolution as organisms with different ancestral origins look more and more similar to each other ANALOGOUS STRUCTURES

Divergence  Also called adaptive radiation  evolution in which two related species gradually become increasingly different.  occurs when closely related species are isolated into different habitats, or a mutation occurs. Convergence  evolution takes place when species of different ancestry begin to share traits of one another because they are in the same environment. DIVERGENCE VS CONVERGENCE Parent species

 A structure in an organism that has lost all or most of its original function in the course of evolution  The genes exist to produce the structure, however, loss of function is due to it no longer being subjected to positive selection pressures in a changing environment  More urgently the feature may be selected against when its function becomes definitely harmful. VESTIGIAL STRUCTURES

CO-EVOLUTION  Occurs when the evolution of one species directly influences the evolution of another.  Examples include all forms of symbiotic relationships:  Predator/prey  Plants/pollinators  Parasitism, commensalism, mutualism  Mimicry: when a species evolves features similar to another. Either one or both are protected when a third species cannot tell them apart.  Camouflage is not co-evolution as adaptations are in response to the environment and not another species

 Carbohydrates are produced by autotrophs through photosynthesis and are used as a source of most organisms  Lipids form essential membranes and protective coverings for cells and organelles  However, all living organisms are dependent on the Nucleic Acids, DNA and RNA to form the proteins that are essential  for the construction of biological structures  the ability of the organism to function. THE MACROMOLECULES

 The study of evolutionary relatedness among various groups of organisms through molecular sequencing of genes and proteins  Since certain genes mutate at regular intervals, the differences can be used as a ‘biological clock” of when species diverged  Forms the basis for the new method of classification called cladistics PHYLOGENETICS

 Developed by Carolus Linnaeus(Carl vonLinne) it groups organisms based upon external morphological similarities LINNAEAN TAXONOMY

PROBLEMS WITH MORPHOLOGICAL TAXONOMY BOTH ARE ROBINS SPANISH ‘MOSS’ AND PINEAPPLES ARE RELATED GENETICALLY MIMICRY!!! NOT TOXIC! MILDLY TOXIC REALLY TOXIC SAME SPECIES DIFFERENT SPECIES ARTIFICIAL SELECTION

 Illustration used to illustrate the phylogenetic evolutionary relationships between species CLAD0GRAMS CLADES: Groups of Organisms that share same traits DERIVED TRAITS: more shared closer evolutionary relationship, ie the more recently their common ancestor lived SPECIATION EVENT ANCESTRAL TRAIT Backbone

SETSTRAITS KANGAROO LAMPREYRHESUS MONKEY BULLFROGHUMANSNAPPING TURTLE TUNA Set 1 Dorsal Nerve cord Notochord XXXXXXX Set 2 Paired appendages Vertebral column XXXXXX Set 3 Paired legs XXXXX Set 4 Amniotic Sac XXXX Set 5 Mammary Glands XXX Set 6 Placenta XX Set 7 Canine teeth short Foramen magnum forward X TOTALS

MAKING A CLADOGRAM

HUMAN: FMF, short canines RHESUS MONKEY: placenta KANGAROO: mammary glands TURTLE: amnion FROG: paired legs TUNA: paired app, vert LAMPREY: DNC

Dorsal nerve cord notochord LAMPREY Paired appendages TUNA Paired legs Amnion Mammary Glands Placenta Foramen magnum forward, short canines FROG TURTLE KANGAROO MONKEY HUMAN IGUANA GOLDFISH RAT E. Summary: 3 TYPES OF INFO -- F. Application: Why? -iguana -rat -goldfish

CLADOGRAM PHYLOGENETIC TREE