Evo Bio Exam #3

• Microevolution


  Evolution occurring within populations, involving adaptive and neutral changes in allele frequencies from one generation to the next
• Macroevolution


  Evolution occurring above the species level, involving the origination, diversification, and extinction of species over long periods of time
• Biogeography


  The study of the distribution of species across space/geography and time
• Species diversity is highest around the equator and tropics
• Biogeographical Provinces


  Subdivisions of biogeographic realms, classified based on biomes or habitat type
• Wallace Line


  Boundary between Southeast Asia and Australia, both sides have similar environments but different species assemblages (due to an underground trench)
• Dispersal


  Movement of populations from one geographic region to another with very limited, or no, return exchange
• Vicariance


  Formation of geographic barriers to dispersal and gene flow, resulting in separation of once continuously distributed populations
• Marsupials


  • Evolved through a mix of vicariance and dispersal
• Area cladogram reveals Antarctic marsupial is most closely related to Australian
• Fauna


  Assemblage of many different species that live together in an ecosystem or region
• Turnover rate


  Number of species eliminated and replaced per unit of time
• Turnover


  Disappearance of some species and their replacement by others
• Standing diversity


  Number of species present in a particular area at a given time
• Diversity Equation

  Diversity 1 + Originations - Extinctions = New Diversity 2
• Diverse taxa have higher origination rate [alpha] than extinction rate [omega]
• There was a higher extinction rate than origination rate with no new mutations, leading to the extinction of dinosaurs
• Diversity


  Directly correlated to increasing temperatures and increasing oxygen levels
• Anagenesis


  Gradual morphological change without speciation
• Cladogenesis


  Rapid morphological change and speciation
• Punctuated equilibria model


  Model of evolution that proposes that most species undergo relatively little change for most of their history but are punctuated by brief bursts of rapid change
• Bryozoans


  • Marine filter feeders that show rapid speciation 6 million years ago
• Gradualism model

  Slow accumulations over time to form 2 lineages
• Ginkgo trees show little polyploidy in gymnosperms, suggesting slow evolution
• Adaptive radiation


  Evolutionary lineage that has undergone exceptionally rapid diversification into a variety of lifestyles or ecological niches
• The Cambrian Explosion (541 million years ago) was caused by an increase in oxygen and rising sea levels creating more habitable areas
• Hawaiian Silverswords


  • 30 species in 3 genera all from single ancestor in California, occupying a wide range of habitats over 5 million years, made it to Hawaii 4 million years ago, with variation in trichomes, ability to collect morning dew and protect from solar radiation, and ability to hybridize
• Hawaiian Honeycreepers


  • Evolved based on food sources and resource partitioning
• Cichlid Fishes


  • Evolved similar body plans through adaptive radiation and convergent evolution in Lake Tanganyika and Lake Malawi of Africa
• Background extinction


  Normal rate of extinction for a taxon or biota
• Mass extinction


  Statistically significant departure from background extinction rates that results in a substantial loss of taxonomic diversity
• The Cretaceous, Triassic, Permian, Devonian, and Ordovician periods all had ocean acidification events
• Permian Extinction


  The biggest mass extinction, caused by volcanic activity in the Siberian Traps, Russia, leading to toxic metal poisoning, ocean acidification, CO2 increase, and anoxic conditions in the marine environment, and chlorine, fluorine, nitrate, nitrite, SO2, acid rain, and ozone depletion in the terrestrial environment
• Cretaceous Extinction

  Also known as the KT/KP (Cretaceous-Tertiary/Paleogene) Boundary, caused by an asteroid impact in the Yucatan Peninsula of Mexico, leading to an iridium spike, changes in carbon isotopes, microtektite formation, and a shift in foraminifera
• The Hell Creek Formation in Montana, which extends into Badlands National Park in South Dakota, shows no dinosaur fossils in the top 3 meters of rock, suggesting they were already going extinct
• 6th Mass Extinction


  Caused by anthropogenic influence, including habitat loss, increasing CO2 levels, warming temperatures, ocean acidification, invasive species, and overcompetition
• Deforestation in Borneo, Indonesia from 1950-2005


  • Production of palm oil led to burning land to plant palms, destroying orangutan habitats
• Systema Naturae = catalogue of 4,162 types

  Typological Species Concept = a species is a set of organisms that resemble one another and is distinct from other sets

  Nominalistic Species Concept = name given based on convenience
• Charles Darwin — “Origin of Species“

  separated barnacles!
• Phylogenetic Species Concept = species are the smallest possible groups whose members are descended from a common ancestor and who all possess defining or derived characteristics that distinguish them from other groups

  NO CONSIDERATION OF REPRODUCTIVE ISOLATION