DINOSAUR FINAL Evolution The process by which different kinds of living organisms are thought to have developed and diversified from earlier forms during the history of the earth Natural Selection The process where by organism better adapted to their environment tends to survive and produce off spring Charles Darwin fitness reproductive success Period ERA Cenozoic Mesozoic Cretaceous Jurassic Triassic Paleozoic Dinosauria The concestor of Iguanodon and Megalosaurus and all of its decendants Principal of Stratigraphy 1 Original Horizontality Description Sedimentary rocks are deposited into flat layers 2 Superposition Bottom oldest progressively younger as you go up 3 Cross Cutting Relations A structure that deforms rock must be younger than the deformed rock 4 Fossil Succession Single non repeating sequence of appearance of species through time Food Chain producers usually plants 1st order consumers 2nd order consumers apex preditor highest on food chain Fossil The physical trace of life s past Trace Fossils record of organisms behavior Body Fossils record of an organisms physical structure Taphonomy The study of burial and fossilization Modes of Preservation Unaltered Bone original hard parts are still present with nothing added This is rare Permineralized common hard part remains but new material is added kind of like cement Recrystallization after burial crystals reorder and grow into each other mineralogy remains but structure is lost Replacement partial complete replacement of crystals of one mineralogy with another Carbonization organic material is distilled under pressure material is lost but carbon film is intact preserves soft tissue Impressions as if the body was pressed into mud and hardened Bone Wars Marsh and Cope Helped find more fossils and increased our knowledge of evolutionary trends Evolutionary Trends Correlated Progression Divergence Convergence Variation Sexual Dismorphism different sexes have different traits Ontogenetic babies look different than adults Geographic populations in different regions have different traits Stratigraphy ancestors may shift in some traits Individual no two individuals in a population are identical Triassi Jurrasic Extinction Wiped out Non dinosauromorphs Pseudosuchains other than ancestors of crocodilians Therapsids other than ancestors of mammals Therefore only leaving Dinosaurs Four methods to infer dinosaur biology Analogies to modern animals Development and diversification distribution of traits in current animals should be present in dinosaurs Biomechanics The sedimentological and trace fossil record Isometry the growth of body part increase directly in proportion to increase in total mass Negative Allometry body part grows proportionally slower than over size increase Positive Allometry body part grow proportionall faster than overall size increase Behaviors Displays various messgaes Sexual Displays to attrack mates Territorial Displays defend territory Defensive Displays to warn off potential threats Specific Recognition features distinction to each species Combat Locomotion adaptions for weight baring vs speed Feeding carnivore and herbivorous Intraspecific within a species Interspecific between species Sexual Dismorphism when the two sexes have distinct forms Ontogenetic Changes some differences between males and females are present at birth Birds Paternal care males watch over the nest Ground Nesting nested on the ground Precocial Able to more around easily shortly after birth Altricial Nest bound wholly dependent on parents for food Lines of Arrested Growth LAGS growth rings one per year when the lines get loser together the dinosaur has stopped growing Skeletochronology Used to determine chronology of age r Selected Have lost of babies Don t invest a lot of time in one baby Chance of survival is small Short life span K Selected Only a few babies Invest a lot of time in their babies Chanced of survival are much better Tend to have longer life spans How and why did dinosaurs get so large Short food chains usually only three steps therefore they receive more of the energy and nutrients Change in atmosphere higher oxygen levels and therefore making it easier to power such high metabolisms Energy Source Metabolic Rate energy used Termperatures Warm Blooded Cold Blooded Comes from inside the cells Turns food into energy to heat endotherm Main energy source is the sun ectotherm Rate of fuel use is high Tachymetabolic fast metabolism Body temperature regulated by internal mechanisms homeotherm Rate of fuel use is slow Bradymetabolic slow metabolism Body temperature fluctuates with external environment poikliotherm Warm Blooded endotherm tachymetabolic homeotherm Cold Blooded ectotherm bradymetabolic poikliotherm Why do we think dinosaurs are warm blooded Upright position o Problem no relationship ever established Origins of birds they were warm blooded o Problem people believe earlier birds were ectothermic cold blooded Growth Rate great rate suggested tachymetabolic o Problem known ectotherms have good growth rates also Why do we think Dinosaurs are cold blooded Small Brain Size o Problem no link between brain size and endothermy Overheating Dinosaurs would overheat if they were warm blooded o Problem some animals can dump excess heat Growth Lines o Problem no connection to blood What they actually are Warm Blooded Why In order for huge dinosaurs to run they must have high metabolic rates and therefore they must be tachymetabolic Aerobic Respiration glucose oxygen water energy Anerobic Respiration food lactic acid energy Mass extinction geologically rapid extinction of many distantly related taxa which are not immediately replaced in ecological space Usually what causes a new era The end of the Mesozoic Era is the boundary between the Cretaceous period K and the Paleogene period Pg Therefore this boundary is called K Pg Not the largest extinction but the most recent one that was really large Who died out Coccolithophorids nannoplankton algae Common in Cretaceous Survived but at much reduced numbers Base of the food chain Ammonoids shelled relative of squids Common in the Mesozoic Food for many reptiles Were extinct But there were a lot of survivors Why did this extinction occur Old predictions Poison gas from comets Diseases Caterpillars ate all of the food what Allergies to angiosperm Supernova The Chicxulub Impact occurred last Iridium an element common in asteroids but rare on earth Walter Alvarez found a lot of iridium