Introduction to Biogeography Lecture PDF

“From the frozen wastelands of Antarctica to the warm, humid rain forests of the tropics; from the cold, dark abyssal depths of the oceans to the near-boiling waters of hot springs; even in rocks several kilometers beneath Earth’s surface—in short, nearly everywhere on Earth—at least some kinds of o...

“From the frozen wastelands of Antarctica to the warm, humid rain forests of the tropics; from the cold, dark abyssal depths of the oceans to the near-boiling waters of hot springs; even in rocks several kilometers beneath Earth’s surface—in short, nearly everywhere on Earth—at least some kinds of organisms can be found. But no single species is able to live in all of these places. In fact, almost every species is restricted to a small geographic area and a narrow range of environmental conditions. The spatial patterns of global biodiversity are a consequence of the ways in which the limited geographic ranges of the millions of species overlap and replace each other over Earth’s vast surface.” Lomolino, et al, 2017  Goals of Today’s Lecture 1. To introduce you to the course organization. 2. To lay the foundations for what we will discuss in this class.  Biogeography (GEOG 2437) - Check out D2L site - Review course outline and schedule Introduction to Biogeography  Biogeographical Truths Life is found nearly everywhere on Earth …but no species is found everywhere Life varies from place to place in a highly non-random and predictable manner Patterns of life recognized by early hominins and ancient civilizations – Essential to survival  What is Biogeography? The science of documenting and understanding the spatial patterns of biological diversity Studying the distribution of organisms, both past and present The study of all the patterns of geographic variation in nature – from genes to communities to ecosystems The study of the elements of biological diversity that vary across geographic gradients – including gradients of area, isolation, latitude, depth, elevation What is Biogeography? What biological processes (e.g., predation, competition), limit species distributions? How does the relative influence of these factors vary across geo- graphic regions, taxa, and time periods? How and why does biological diversity vary over Earth’s surface?  Why Study Biogeography? Helps us make sense of the forces structuring the natural world A holistic discipline in the natural sciences – Combines and synthesizes inputs from genetics, geology, paleontology, anthropology, meteorology, oceanography, ecology… Supports conservation – Assess changes in biodiversity due to habitat fragmentation or climate change – Assess spread and establishment of invasive species  Fundamental Terms & Concepts Historical biogeography – Focuses on long term processes that unfold over evolutionary or geological time periods – Larger scale geographic areas (often); higher taxonomic levels, taxa that are extinct – e.g., What is the history of the group, and where did earlier members of the group live? Ecological biogeography – Generally deals with shorter time periods, smaller geographic scales, and extant taxa – e.g., What is the relationship between mountain elevation and species diversity of butterflies?  Fundamental Terms & Concepts Phytogeography Zoogeography – Study of plant distributions – Study of animal distributions – Flora – Fauna In reality…highly intertwined  Biogeography: Integrations A synthesis of biology (life science) and geography (earth science) Evolutionary biology – Role of geographic isolation in evolution; maintains genetic differentiation Ecology, climatology and physiology – Distributions constrained by predators, parasites, competition for food / resources – Distributions constrained by physiological abilities to survive / reproduce in certain climatic conditions Geology – Plate tectonics Penguins and Polar Bears Lomolino et al, 2017  Exploration and Biogeography 18th C: “Age of Exploration” Explorers encountering numerous plant and animal specimens – Need for standard, systematic scheme to classify Carolus Linnaeus (1707-1778) – Binomial nomenclature – Considered origin and spread of life – Post-Creation and post-biblical flood – animals and plants colonized down exposed slopes of an exposed mountain (“Paradisical” Mountain or Mt Ararat), then worldwide Early Hypotheses for Diversity  Exploration and Biogeography Georges Buffon (1707-1788) – Buffon’s Law: Different parts of the globe, even with similar climatic and environmental conditions, contain different species – Postulated northern origin of all life forms (Creation), and southward spread with changing climate – Theorized that organisms “improved” or “degenerated” as they became isolated, and the survival of improved forms – The Earth and its species were dynamic!  Voyages of James Cook, with naturalists Lomolino et al, 2017  Voyages of James Cook, with naturalists Johann Forster Sr. Important contributions to plant biogeography Buffon’s Law applied to plants Plant diversity increases toward equator Larger islands (with more varied habitats) have more plant species than smaller islands Lomolino et al, 2017  Exploration and Biogeography Alexander Von Humboldt (1769-1859) – Founder of plant geography (phytogeography), among many others – Recognized world is divided into natural biogeographical regions, with distinct assemblage of plants/animals – Took a holistic approach; nature as interconnected phenomena  Exploration and Biogeography Augustin de Candolle (1778-1841) – Contributed to knowledge of plant dispersal and barriers to dispersal – Studied plant adaptations to heat, moisture – Stressed importance of competition for resources – Coined the word “endemic” – Ideas used by Darwin  How Old is The Earth? End of the 18th C… Biogeographic knowledge growing, but… – Primarily descriptive – “How” and “why” for explaining patterns was lacking Distribution maps based on ecological biogeography Historical biogeographical approach needed to explain distribution, but… – Lack of understanding and acceptance of ancient age of earth – Biblical interpretation: Earth only a few thousand years old  How Old is The Earth? James Hutton (1726-1797) Charles Lyell (1797-1875) – Recognized Earth’s history is – “Principles of Geology” immense – Popularized uniformitarianism – Uniformitarianism: the present and ancient age for Earth is the key to the past  Darwin, Wallace and Evolution Charles Darwin (1809-1882) – Naturalist aboard the HMS Beagle – Finches: ancestral South American species had colonized Galapagos Islands, then over time radiated and adapted to different lifeways – Postulated evolution by natural selection Evolution: Life on Earth is NOT fixed & unchanging Darwin’s Voyage  Darwin, Wallace and Evolution Alfred Russel Wallace (1823-1913) – Voyages of exploration – Jointly postulated evolution by natural selection – Noted biogeographic divisions of animal populations 1854 trip through Malay Archipelago Darwin, Wallace and Evolution  Dispersal vs Vicariance Historical explanations (vicariance, dispersal) of the disjunct distribution of two taxa (A, B). (Modified from Nelson & Platnick, 1984 and Cranston & Naumann, 1991).  Explaining Disjunctions Disjunct distributions presented a problem – E.g., Glossopteris fossils (300-250 mya) – How did this distribution arise? – Wind? Land bridges? – Continental movement?  Explaining Disjunctions Lomolino et al, 2017  Explaining Disjunctions Continental Drift: Solid Earth is NOT fixed & unchanging  Late 20th Century Progress Cladistics – Organisms categorized into groups (“clades”) based on hypothesis of most recent common ancestry – Based on shared derived characteristics  Late 20th Century Progress Molecular genetics – Uses fundamental characteristics of organisms (in DNA) to determine evolutionary relationships Maturation of ecology as a science – Integration with biogeography – Ecological biogeography focusing on biotic and abiotic factors that influence distribution – Seminal work on island biogeography (MacArthur & Wilson, 1967) Marine biogeography as the “final frontier” – Growth in knowledge of marine realms – Technological innovations; deep sea exploration, satellites Questions / Comments?  Readings Review readings Cox et al, Biogeography: an ecological and evolutionary approach – 10th edition (2020): pages 1-19 – 9th edition (2016): pages 1-16  Next time Patterns of Distribution – Biology and taxonomy basics – How we describe distributions of biota – Limits on distributions Readings for next unit Cox et al, Biogeography: an ecological and evolutionary approach – 10th edition (2020): pages 39-92 – 9th edition (2016): pages 33-85