BIOB 272 1st editionLecture 33 Outline of Last Lecture Human Evolution Day 2I. Neanderthals- Interbreeding- Genes Enriched/ De-enriched forII. Denisova Cave Hominin Inhabitation- Denisovans- High Adaptation to High Altitude- Tibetan and Han ChineseIII. “Leaky” Replacement Hypothesis for Expansion out of AfricaIV. What Makes us Human, Genetically?V. Evolution of Brain Regions Involved in LanguageOutline of Current Lecture MacroevolutionI. Macroevolution vs. MicroevolutionII. Life: the first 3 billion years- Pre-Cambrian Fauna- Cambrian Fauna- Cambrian Explosiono What triggered the Cambrian Explosion Morphological InnovationsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute. Ecological Opportunities- RodiniaIII. Calculating Rates of Origination/Extinction from Fossils- Adaptive Radiationi. Ecological Opportunityii. Morphological InnovationIV. Causes of Decline in Diversity- Extinctioni. Background Extinctionii. Mass Extinction- The Five Mass ExtinctionsV. K-T Extinction- Causes- Evidence- Other Disasters the Asteroid CausedVI. Mass Extinctions Random?VII. Earth’s Sixth Mass Extinction - Humans- Habitat Loss- Increasing CO2 Acidifies the OceanCurrent LectureMacroevolutionI. Macroevolution vs. Microevolution- Macroevolution: Evolution patterns above the species levelo Origination, diversification, extinction- Microevolution: Evolution occurring within populationso Adaptive and neutral changes in allele frequencies- Microevolution is the ultimate source of macroevolutionary patternsII. Life: the first 3 billion years- Earth= about 4.5 billion years old- Pre-Cambrian Fauna (565-544 mya)o 1st unequivocual evidence for animals= sponges and jellyfish- assymetrial or radial symmetry- Cambrian Fauna (543-495 mya)o Best fossils found at Field, BC: quarry where fossils were found= Burgess Shale- formed for soft marine sediments- show amazing detail of animals that were alive 520-515 mya- Cambrian Explosiono All major phyla except jellyfish and sponges first appear in the fossil record over a 40 my period o All major animal lineages over about 1% of geologic timeo What triggered the Cambrian Explosion Morphological Innovations: sessile filter feeders to diverse predators, filter feeders, grazers, scavengers,etc. Ecological Opportunities: increased oxygen= photosynthetic algae to higher metabolism and larger bodies- preceding mass extinction (to open niches)?- Rodinia: The “waterworld”= Earth in the time leading up to the early Cambian (650 mya)- this is NOT Pangaeao About 550 mya Rodinia broke up leading to extensive shallow seasIII. Calculating Rates of Origination/Extinction from Fossils- Term explosion implies that the rates of speciation increased during the Cambriano Interplay between speciation and extinction determines diversityo Originations (speciation)- extinctions= diversity- Extinction rate often tracks origination rate- Increase the diversity of taxa= increase origination rate and decrease extinction rate- Adaptive Radiation (Cambrian Explosion): rapid diversification of a single lineage into a large group of ecologically or morphologically diverse descendent speciesi. Ecological Opportunity: results in empty niches and/or isolation from competitiono I.e. Hawaiian Honeycreepers Monohyly shown from phylogeny Descended from a single species of finch in the last 10 million yearso I.e. Hawaiian Silverswords Rapid expansion of monophyletic group resulting in a clade of morphologically and/or ecologically diverse specieso I.e. Darwin’s Finches: Within last 1 million years= huge expansion= 120 genomes= shows radiation occurred in last 1 mil years Within last 1 million years= huge expansion= 120 genomesii. Morphological Innovation: when a key trait allows access to an entirely new ecological/evolutionary space I.e segmentation in arthropods= over 100,000iii. Many Show a combination of both of these- Most adaptive radiations involve exploitation of environments not occupied by competitors- Key innovations can transform how organisms interact with their environmento Paves the way for adaptive radiationIV. Causes of Decline in Diversity- Extinction: occurs when a member of a clade dies (species or group of species)o Ultimate fate of all specieso Overall diversity can decline when extinction increases or origination decreaseso Background Extinction: normal rate of extinction= 96% of extinctionso Mass Extinction: Statistically significant increase about background extinction rate- The Five Mass Extinctionsi. Ordovician – climate change (glacial cycles)ii. Devonian – climate change (cooling)iii. Permian – climate change, ocean acidification, volcanism (CO2)iv. Triassic – climate change (warming, increased CO2)v. Cretaceous – climate change (cooling), catastrophic eventV. K-T Extinction- Causes: Luis and Walter Alvarez proposed in 1980 that a giant meteor hit Earth= caused destruction that caused the extinctions- Evidence:i. Exhibit A: increase in amount of iridium in a thin clay layer all over Earth between Cretaceous and Tertiary rocks- Iridium is rare on Earth but common in meteoritesii. Exhibit B: Abundance of shocked quartz in the K-T boundary layers of clay in some parts of the worldiii. Exhibit C: Presence of micro tektites in K-T boundary clays= found glass like balls that form when molten material, flying through the air, cools before it hits the ground- Evidence shows that the meteor hit on the Yucatan Peninsula about 65 mya- Other Disasters the Asteroid Caused:o Acid rain, wild fires, volcanic eruptions, intense cooling, decreased light, tsunami, ecological falloutVI. Mass Extinctions Random?- No, biology probably mattered a lot during K-T event, dinosaurs and many marine organisms were completely wipes out, but other groups were relatively unscathed (mammals)- Mass extinctions- depending on the cause- may select for certain characteristics of species or other groupsVII. Earth’s Sixth Mass Extinction- has it already began?- current extinction rates are on par with previous mass extinctions- Human Migration/ colonization= huge cause of most extinctions- Habitat Loss= leads to extinction. Increasing amount of habitat loss occurring- Climate change= increases temperatures= increases CO2= Acidifies the