8_27 lecture.pdf

BIOL 3309 Principles of Ecology Life on Land Dr. Joseph Manthey Texas Tech University Fall 2024 Class notes: TopHat participation starts counting next week HE+ section will be updated on Blackboard next week 1st in-class quiz next Tuesday Natural h...

BIOL 3309 Principles of Ecology Life on Land Dr. Joseph Manthey Texas Tech University Fall 2024 Class notes: TopHat participation starts counting next week HE+ section will be updated on Blackboard next week 1st in-class quiz next Tuesday Natural history Historically driven by collection Collect Name and categorize Display and archive Largely descriptive Often provides the information leading to questions in the Natural history forms the scientific process foundation upon which modern ecology developed. 1800s: formations Now: biomes Natural History is key to defining biomes Climate and predominant plants Think rain forest and desert Part 1: Climate Learning Objectives: 1.Difference between climate and weather 2.What causes short- or long-term variation in climate? 3.How do solar radiation and the Coriolis effect cause the Earth’s wind patterns? Climate vs. weather Weather: The temperature and moisture conditions for a specific place and time Climate: The long-term pattern of weather in a locality, region, or even over the entire globe Climate and weather differ in spatial extent and timescale. Climate is long-term average of weather patterns.  This week in 2022 Climate vs. weather This week in 2024 What causes variation in climate? Uneven heating of the earth’s spherical surface by the sun and the tilt of the earth on its axis combine to produce predictable latitudinal and seasonal variation in climate Solar radiation Tilt of earth’s axis affects intensity of incoming solar radiation Solar radiation = solar energy with capacity to heat earth’s surface Axis tilt leads to spread of sunlight over greater area, less energy per unit area, less heating Spread over greater area of atmosphere, less sunlight reaches earth  Polar versus tropics Large variation at poles Extreme seasonality in day length and temperature Small variation in tropics Small variation in day length and temperature Direct solar radiation from 23.5°N (Tropic of Cancer) to 23.5°S (Tropic of Capricorn) Recall tilt of earth’s axis is 23.5° Day length 23.5° tilt towards sun in summer, away in winter Long summer days, short winter days Long-term climate fluctuations ~ last 1-2 million years Tilt and solar radiation also drive global precipitation and atmospheric circulation So, what about wind and rain? Hadley Cell (at/near equator) Hot air rises, cool air falls Hot air can hold more moisture than cool air Air flows from high pressure to low pressure Extent of Hadley Cells Heavy rain around equator Deserts around 30°N and 30°S What about the rest of the planet?  Ferrel Cell Cool dry air falling at Horse 30° creates high Latitude pressure zone, spreads north and south Dry air spreading toward pole picks up Intertropical moisture Convergence Meets cold polar air Zone flowing south Polar Cell Spreading toward pole, cools and falls to spread back towards equator Coriolis effect North-South circulation caused by convection cells East-West circulation caused by Coriolis effect Coriolis effect causes apparent deflection of winds clockwise in northern hemisphere and counterclockwise in southern hemisphere  Horse Hadley Cells: Latitude Trade Winds E -> W Ferrel Cells: Westerlies Intertropical W -> E Convergence Zone (ITCZ) Polar Cells: Polar Easterlies E -> W Hurricanes North South rwu.edu Check out this wind resource: https://earth.nullschool.net/#current/wind/surface/level/orthographic=-104.80,24.92,550  Temperate versus tropical seasonality Temperate: Spring, Summer, Autumn, Winter Tropical: Rainy, Dry Equatorial Rainy seasons Solar equator: Region of strongest solar radiation shifts from Tropic of Capricorn (23.5°S) to Tropic of Cancer (23.5°N) Passes over equator twice One rainy season at Tropic of Cancer, Capricorn Two rainy seasons at Equator  Continental and oceanic effects Water has high specific heat Specific heat = amount of heat (energy) per unit mass required to raise the temperature by one degree Celsius Material Specific Heat (J/g °C) Soil 0.79 Land heats and cools much faster Aluminium 0.88 Wood 1.71 than water (oceans, lakes) Water 4.19 Continental and oceanic effects Large bodies of water moderate climate Water cools air in summer, warms Station Latitude Min. Max. Range air in winter (°C) (°C) (°C) Continental climate Lubbock 33° 40’ 4.56 26.83 22.27 more extreme Airport No moderating Los Angeles 33° 56’ 13.67 20.89 7.22 effect of water Airport Los Angeles mean ocean temperature: 17.2°C Part 2: Climate Diagrams Learning Objectives: 1.Read and interpret climate diagrams Climate diagrams Climate diagrams Invented by Heinrich Walter (1985) Summarize climatic information using a standardized structure 1. Locality 2. Elevation 3. Mean monthly temperature 4. Mean monthly precipitation 5. Frost period (based on mean daily minimum temperature) Temperature (°C) plotted on primary Precipitation (mm) vertical axis plotted on (primary y-axis) secondary y-axis 10°C = 20 mm Plant growth needs 20mm/10°C Look at relative position of precipitation and temperature lines. If precipitation > temp, sufficient moisture for plant growth What latitude? Climate diagrams and terrestrial biomes Desert: Tropical dry < 300 mm, forest: many much ~1000 mm, less summer rainy season Mediterranean Tropical : 300 – 600 rainforest: >2000 mm, summer mm, drought year round Part 3: Terrestrial Biomes Learning Objectives: 1.Major characteristics of Earth’s major biomes 2.Combine knowledge of climate diagrams and biome characteristics  Natural History is key to defining biomes Terrestrial Biomes Climate Predominant plants What makes up a terrestrial biome? 1) Climate 2) Soils + Nutrients 3) Fire frequency Tropical rainforests Most within 10° of equator Tropical rainforests 5% of land area (used to be 12%), but 50% (or more) of species Very dense canopy, competition for light Interesting Adaptation: Epiphytes (plants that grow on other plants) and vines are very common Tropical dry forest 0° - 25° Note opposite rainy season in Northern and Southern hemisphere May be dry for up to 8 months Little variation in warm temperature Tropical savanna 10° - 20°, north or south of tropical dry forests Short rainy season, during warm months Tropical savanna Interesting Adaptation: Dry season drought Lightning strikes start fires Trees and shrubs generally are not fire resistant Grasses quickly resprout Tropical dry forest and savanna Interesting Adaptation: High rate of photosynthesis during wet season Trees are deciduous, drop leaves dry season Tropical dry forest and savanna Interesting Adaptation: Remember the Hadley Cells? Desert 30° N and S 20% of earth land surface Water loss (evaporation and transpiration) usually exceeds precipitation Not necessarily hot, not necessarily low precipitation Continental climate! Latitude Desert Interesting Adaptation: Plants have many adaptations to reduce water loss Reduced/no leaves Hairs Leaves only when rain Ephemeral plants Dormant seeds in soil until wet period Desert Interesting Adaptation: Sandgrouse and water Mediterranean Woodland and Shrubland aka Chaparral (NA), Matorral (SA), Fynbos (S. Afr.), Mallee (Aus.) Seasonality is key Hot dry summer, fire plays a key role Mediterranean Woodland and Shrubland Interesting Adaptation: Typical plants are fire adapted Herbaceous plants don’t grow in hot, dry summer Avoid fire Many trees have fire-resistant bark  Mediterranean Woodland Wine producing regions and Shrubland Temperate Grassland Temperate grasslands mostly gone -e.g., tallgrass prairie >97% gone Why? Temperate Grassland Interesting adaptation Herbivore predation avoidance Temperate Forest 30° - 50° May freeze, but temperatures not extreme More rainfall than grasslands Temperate Forest Interesting Adaptation Songbird migrations Black and white warbler Boreal Forest (aka Taiga) Northern hemisphere only Why? 11% of global land area Extreme temperature variation Long winters (> 6 months) = short growing season Boreal Forest (aka Taiga) Interesting adaptation: Frogs in long winters? Antifreeze-like proteins in blood https://home.nps.gov/gaar/learn/nature/wood-frog-page-1.htm Tundra North of arctic circle Cold Typically low precipitation Extreme short growing season Part 4: Texas Biomes Learning Objectives: 1.Have a broad understanding of biome diversity in Texas Forests Shrubland Deserts, Grasslands, and Savanna Part 5: Mountains Learning Objectives: 1.Mountain range impacts on climate Mountains Rain shadow effect Cooling with altitude: 5 – 8°C cooling every 1000m Adiabatic cooling: as air rises, pressure is reduced, air expands and cools Cool air holds less moisture, leads to precipitation Rain Shadow: Air arriving on opposite side of mountain is dry Mountains Higher Temperature Elevation Lower Temperature Lower Precipitation Higher Precipitation Mountains Cooling with altitude: 5 – 8°C every 1000m