class: center, middle, inverse, title-slide .title[ # Life and the Environment ] .author[ ### Daijiang Li ] .institute[ ### LSU ] --- class: left, middle class: left, center, inverse .font300[Announcements] --- class: center, top ## An understanding of the physical environment is key to understanding all ecological phenomena  --- background-image: url('figs/biomes.svg') background-position: 90% 50% background-size: contain class: left, top # .blue[Biomes] --- # Biomes #### Large-scale biological communities sharing _similar_ **plant** growth forms; often owing to convergent adaptations to similar physical environments; determined largely by temperature and rainfall (climate) .center[] ??? how does a particular environment result in similar plants? selective pressure lead to similar functional traits through evolution why defined by plants? plants form the foundation of life on earth; they are primary producers --- # Primary productivity on Land  --- # Primary productivity in Oceans ### Almost half of all primary productivity on Earth  --- # Ecoregions (867 distinct ones) .center[] Olson et al 2001 _Bioscience_ .font200[Other factors such as soil types and elevation can also have strong influences] ??? how many biomes depends on who do you ask; or how different to go --- # Major Determinants of Global Climate ### 1. Spherical shape of the earth: uneven heating .center[] ??? while the global distribution of biomes is determined by climate, what determines the distributions of climate? --- # Major Determinants of Global Climate ### 2. Revolution of the Earth around the Sun on a tilted axis (seasons) .center[] <!--  --> --- # Seasons  --- # What is the main cause of winds? .font200[ a. the rotation of the earth around the sun b. the rotation of the earth on its axis c. the differential heating and cooling of different geographical locations on earth ] --- background-image: url('figs/hot_air.png') background-position: 0% 50% background-size: contain class: right, middle .pull-right[ ## Hot air expands & rises ## As air rises, it expands and cools ] --- # Wind is caused by differential heating of the Earth’s surface  --- background-image: url('figs/sun_heat.png') background-position: 0% 50% background-size: contain class: right, middle .pull-right[ ## Wind is caused by differential heating of the Earth’s surface ] ---  --- # Major Determinants of Global Climate ### 3. Rotation of Earth around Earth’s axis. Creates **Coriolis effects** (conservartion of momentum) .pull-left[  ] .pull-right[  ] --- # Air circulation patterns (surface) .pull-left[  ] .pull-right[] --- ## Ocean currents are driven by winds and redistribute heat, and modified by Coriolis effects  --- # Rising warm airs --> Rain  ---  --- ## Why does it rain on the windward side of mountains, and why is it dry on the leeward side?  .right[Kauai 22° N] --- # Rain shadow effect  --- background-image: url('figs/Rain_shadow_effect2.png') background-position: 0% 50% background-size: contain class: right, bottom # Rain shadow effect --- background-image: url('figs/deserts.png') background-position: 0% 50% background-size: contain class: center, top # Climate and World Biomes --- background-image: url('figs/biomes_shape.jpg') background-position: 0% 50% background-size: contain class: right, top .pull-right[ ## Terrestrial biomes largely determined by temperature and precipitation ] --- # Tropical rain forests .pull-left[ .middle[] ] .pull-right[ .font150[ Dominant canopy plants: broad-leaved evergreen trees Also epiphytes, lianas, palms, and generally sparse understory More-or-less continuous growing season Contain ~50% of Earth’s species & ~37% of terrestrial carbon in ~11% of terrestrial veg. cover ] ] --- # Tropical seasonal forests and savannas .pull-left[ .middle[] ] .pull-right[ .font150[ Tropical dry forests Thorn woodlands Tropical savannas Generally smaller-stature trees and more deciduousness than in rain forests Resource availability, fire & large herbivores help determine the balance between grasses vs. woody species Pronounced wet / dry seasons ] ] --- # Deserts .pull-left[ .middle[] ] .pull-right[ .font150[ Populations of plants & animals are often sparse (owing to resource limitation) Succulence (fleshy water-storage tissue in leaves, stems, etc.) is common among the plants Sustained periods of high temp. & low water avail. ] ] --- # Temperate Grasslands .pull-left[ .middle[] ] .pull-right[ .font150[ Dominant plants = grasses Greater temp. variation than tropics Relatively warm, moist summers & cold, dry winters Some have sufficient rainfall to support woody veg., but fire & grazers maintain grasslands Soils rich in organic matter (especially from proliferation of grass roots) ] ] --- background-image: url('figs/grassroots.jpg') background-position: 0% 50% background-size: contain class: center, top --- # Temperate Shrubland and Woodlands .pull-left[ .middle[] ] .pull-right[ .font150[ Winter rainy season (e.g., Mediterranean-type climates – water and temperature conditions for growth are somewhat asynchronous) Fire is a common feature Evergreen, sclerophyllous (tough, leathery) leaves are common ] ] --- # Temperate Deciduous Forests .pull-left[ .middle[] ] .pull-right[ .font150[ Tree-dominated Deciduous leaves owing to freezing temperatures Sufficient rainfall & soil fertility to support tree growth (trees largely outcompete grasses) ] ] --- # Temperate Evergreen Forests .pull-left[ .middle[] ] .pull-right[ .font150[ From warm coastal zones to cool maritime or continental climates Generally on nutrient-poor soils Northern Hemisphere – needle-leaved conifers Southern Hemisphere – needle-leaved & broad-leaved trees ] ] --- # Boreal Forests / Taiga .pull-left[ .middle[] ] .pull-right[ .font150[ Generally above 50º N latitude Coniferous tree species in continental climate zones and deciduous birch forests in some maritime zones Extreme weather Permafrost common Largest terrestrial biome, with ~33% of forested land ] ] ??? Immense carbon pool --- # Tundra .pull-left[ .middle[] ] .pull-right[ .font150[ Beyond latitudinal tree line, e.g., above ~65º N latitude Dominated by sedges, grasses, forbs, lichens, mosses & prostrate shrubs Primarily in the Arctic Extreme weather and adaptations for prolonged dormancy Permafrost very common ] ] --- # Mountains: A Diversity of Biomes  .right[[Elsen et al. 2018](https://paulelsen.files.wordpress.com/2019/10/elsen-et-al.-pnas-2018.pdf)]