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SCI 160 Week 5 • The Final Frontier… • Things we’ve skipped in the text: • • • • • • • Plant Form and Function Plant Life Cycles Animal Bodies and Functions Circulation & Respiration Nutrition, Digestion & Excretion Defenses Against Disease Chemical Control in Animals – Endocrine Systems • The Nervous System • Animal Reproduction Tonight… • Chapters 27 to 30 - The BIG picture • • • • Population Growth Community Interactions How Ecosystems Work Earth’s Ecosystems Chapter 27 • Population Growth Ecology • We are now concerned with ecology – the study of organisms’ interactions with each other AND nonliving parts of their environment. • Some more definitions (small to large): • A population – all members of a particular species who live in a particular area • A community – all interacting populations of different species who live in a particular area • An ecosystem – all communities within a defined area along with their non-living components How Are Populations Distributed in Space and Time? • Individuals in Many Populations Clump Together in Groups – Advantage: can search for food together, reduces the odds of being eaten by predators, improves mating possiblilities – Figure 27.1 Population distributions (p. 548) clumped Even Steven • Uniform distributions –keep a relatively constant distance between each other. • Can defend territories from invading species • Can escape destruction by local disasters (fire/flood) uniform Random Distributions • The species don’t need social groups • And/or and resources are not scare random How Do Populations Grow? • Births, Deaths, and Migration Determine Population Growth – Population Growth Can Be Expressed As a Rate • Like a velocity • Simple even if you bury it in math Factors Affecting Population Numbers Locally… Growth… • A Constant Growth Rate Increases Population Size Rapidly Biotic Potential The Biotic Potential is the maximum rate at which a population could increase under ideal conditions. Different species have different biotic potentials.. How fast is fast? • A Population’s Growth Rate Depends on Patterns of Reproduction – Some Species Produce Large Numbers of Offspring Quickly – Other Species Produce Fewer But Longer-Lived Offspring • Figure 27.2 J-shaped exponential growth curves (p. 551) bacteria Exponential growth curves are J-shaped. time (minutes) number of time (minutes) bacteria 0 1 20 2 40 4 60 8 80 16 100 32 120 64 140 128 160 256 180 512 200 1024 220 2048 eagles Reproduction begins at 4 years. time (years) 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 Reproduction begins at 6 years. time (years) number of number of eagles (i) eagles (ii) 2 2 2 2 4 2 8 4 14 8 28 12 52 18 100 32 190 54 362 86 630 142 1314 238 2504 392 644 4770 9088 1066 17314 1764 How Do Populations Grow? – Delayed Onset of Reproduction Slows Population Growth • Are Americans having children later? – Death Rate Also Influences Growth Rate • Figure 27.3 The effect of death rates on population growth (p. 552) bacteria no deaths 10% die between doublings 25% die between doublings time (hours) How Is Population Growth Regulated? • Rapid Growth Cannot Continue Indefinitely – Some Populations Fluctuate Cyclically • Figure 27.4 A boom-and-bust population cycle (p. 552) • Figure E27.1 Population cycles of predators and prey (p. 554) • Figure E27.2 Experimental predator–prey cycles (p. 554) • Figure 27.5 Lemming population cycles (p. 553) Nutrients are depleted. Favorable growth conditions occur. hares (prey) lynx (predator) year bean weevils (prey) branconid wasp (predator) generation approximate number of lemmings per acre How Is Population Growth Regulated? – Why are the peaks and valleys above not always the same? • Ecosystem Changes May Allow Temporary Rapid Growth – Extra food and water/Less food or water – A new species invading the area = an exotic species • Environmental Resistance Limits Population Growth – You can get a stable population – Birth rate is balanced by death rate – Figure 27.6 The S-curve of population growth (p. 553) number of individuals (environmental resistance) carrying capacity equilibrium (biotic potential) rapid growth time How Is Population Growth Regulated? – Density-Independent Factors Limit Population Size • Natural disasters, weather, human activities – Density-Dependent Factors Have Greater Effect As Population Density Increases • Predator and prey cycles • OR parasite and host • Figure 27.7 Predators help control prey populations (p. 555) How Is Population Growth Regulated? – Predators Exert Density-Dependent Controls on Populations • The more prey there is, the more frequently the predators find them – Parasites Spread Faster When Host Population Density Is High • In the same way, when there are more hosts, the parasites spread more easily – Populations Can Soar or Crash When Predator–Prey Relationships Are Disrupted • Break the natural cycle, and numbers can get out of hand! – Competition for Resources Helps Curb Population Size • Then starvation is needed to control numbers How Is the Human Population Changing? • Is it creepy thinking of humans in the same way we think of animals/plants/parasites? The same rules can apply. • Figure 27.8 Human population growth (p. 557) Agricultural advances billions of people bubonic plague Technical and cultural advances Industrial and medical advances How Is the Human Population Changing? • Technological Advances Have Increased Earth’s Carrying Capacity for Humans – Early Tools Allowed Human Populations to Spread and Prosper • There was a cultural revolution when fire was discovered • Tool, weapons, shelter, protective clothing – Agriculture Fostered Population Growth • 8000BC crops and domesticated animals replaced hunting and gathering – Explosive Growth Began with the Industrial Revolution • bacteria, smallpox etc. • Population Growth Continues Today But Is Unevenly Distributed – All countries are not reproducing equally – Population in developing vs. developed countries (p. 558) population (billions) 2004: 6.3 billion developing countries developed countries How Is the Human Population Changing? • The Age Structure of a Population Predicts Its Future Growth – Broken into pre-productive, reproductive, and post-productive slices – The overall shape tells you if the population is growing, steady, or shrinking – Age structure diagram (p. 558) postreproductive (46-100 years) reproductive (15-45 years) prereproductive (0-14 years) expanding stable shrinking 27.4 How Is the Human Population Changing? – 27.4.3.1 Almost All Future Population Growth Will Be in Developing Countries • Figure 27.9 Age structures compared (p. 559) • Figure 27.10 Population growth by world regions (p. 560) Developed countries 2003 age postreproductive (45-79 yr) reproductive (15-44 yr) prereproductive (0-14 yr) millions of people 2025 age Developing countries millions of people World average 1.3% Developing countries 1.6% World regions Africa 2.4% Latin America/Caribbean 1.7% Asia (excluding China and Japan) 1.6% China 0.6% Developed countries 0.1% N. America 0.5% Europe -0.2% annual natural increase How Is the Human Population Changing? – Fertility in Europe Is Below Replacement Level – More deaths than births! But… • The U.S. Population Is Still Growing Rapidly – Natural increase of 0.6%/year – With immigration 1.4% – Example: In 2002: 4.1million more that year, 11,000 more a day – 2050 could be 420 million (up from 295 million presently) – Figure 27.11 U.S. population growth (p. 560) U.S. population (in millions) (1790-2004) year Chapter 28 • Community Interactions Why Are Interactions in Ecological Communities Important? • An ecological community consists of all the interacting populations in an ecosystem. • Can be beneficial, harmful, or have no effect on any two interacting populations • Table 28.1 Interactions within Communities (p. 568) Why Are Interactions in Ecological Communities Important? • Community Interactions Help Limit Population Size – This can be messed up when members of foreign populations are introduced – Completion goes out of balance no natural predators for introduced species – Figure E28.1 Exotic species (p. 570) Zebra Mussels Kudzu Water hyacinths The rosy wolf snail attacks Hawaii’s native snails Why Are Interactions in Ecological Communities Important? • Community Interactions Influence Evolutionary Change • Wolf and Deer again • Wolves prey on the weakest deer and the weakest deer can’t catch fast deer • This concept is called coevolution What Are the Effects of Competition among Species? • When you have interspecific competition, you have different species competing for the same resources • Each Species Has a Unique Place in Its Ecosystem – Those places are referred to as niches – A niche can be defined by • • • • • range of temperature moisture available nutrients/food/prey time of day food/moisture is available even soil pH (acidity) Niches • BUT The Ecological Niches of Coexisting Species Never Overlap Completely • Often, one survives (a slightly wider range of flexibility) and the other dies out. • Example: two paramecium in a flask… P. aurelia P. caudatum grown in separate flasks grown in the same flask Healthy competition • Critters (species) can coevolve to decrease competition (greater chance of survival that way) • Called resource partitioning • The ones that don’t compete as much as the rest of the species has the greater food/resource supply and survives and reproduces better Warblers as examples of Resource Partitioning each species spends at least 50% of foraging time in designated areas What predators and prey do to each other … • We see the current state of a long playing arms race. Camouflage assists predators • Where ARE the kitties? • and Figure 28.6 (p. 574) Warning coloration – Animals with bright coloration are often poisonous – Figure 28.7 (p. 574) Warning mimicry • Harmless animals may look like harmful ones (Coral Snake and Mt. King Snake) • Distasteful species may end up looking like one another…a universal sign of bad taste (Monarch and Viceroy butterflies) • Or prey can mimic another predator (snowberry fly mimics the jumping spider) • Or they can startle- reveal what looks like large eyes that would belong to a big predator Chemical warfare • Skunks! • Other examples: • Bombardier sprays a hot toxic brew (pictured) • and Monarch caterpillars feed on milkweed that contains a powerful toxin • Figure 28.11 (p. 576) Symbiosis – working together • Parasites – harm, but don’t immediately kill the host (if their life cycle is short, what do they care?) • How does that apply to diseases? – Ebola? – Flu? – AIDS or mad-cow disease? • Lichen = Fungi + Algae (Fungus= protection, Algae = photosynthesis/food • Cows and termites can only digest cellulose containing plant tissue due to protists and bacteria in their guts (you too for many vitamins and digestion) • Figure 28.12 Mutualism (p. 577) Eyelash Mites Keystone species • The controller of other species in a region/habitat/niche • Remove it and other populations explode or crash • Figure 28.13 (p. 577) – The starfish Pisaster controls mollusks – The elephant feeds on small trees and bushes, preventing the encroachment of the forests, preserving the grasslands for everything else All good things must come to and end Jean Luc… • When something disastrous happens to a region, life ‘rushes’ in to grab hold again. • Pioneers (hardy organisms) lead the way • Then it progresses to a stable climax community eventually results • Figure 28.14 New life emerges after disruption (p. 578) Successions… • Figure 28.15 Primary succession (p. 579) – Starts with bare rock, sand or a clear glacial pool • Figure 28.16 Secondary succession (p. 580) – Starts after an existing ecosystem is disrupted or destroyed (farm land or volcanic eruption) • Example: Figure 28.17 Succession in a freshwater pond (p. 581) lichens and moss on bare rock 0 bluebell, yarrow blueberry, juniper time (years) jack pine, black spruce, aspen balsam fir, paper birch, white spruce, climax forest 1000 plowed field 0 ragweed, crabgrass and other grasses asters, goldenrod, broom sedge grass blackberry time (years) Virginia pine, tulip poplar, sweet gum oak-hickory climax forest 200 Chapter 29 • How Do Ecosystems Work? • Biosphere 2 – – – – – – – (What was Biosphere 1?) 1991: a 3 acre glass and steel ‘greenhouse’ 900,000 gallon ocean 8 people for 2 years at a time sealed in CO2 (rich soil and concrete) Nitrous Oxide (rich soil) Ants (stressed all vertebrates, ended pollination etc.) – Ultraviolet (photosynthesis not as efficient) – Yams did well… with strange side effects How Do Ecosystems Obtain Energy and Nutrients? • Energy flows through the Earth system • Nutrients are cycled around (reused) • Trivia: Has anyone else breathed the air or drunk the water you are breathing and last drank? • Figure 29.1 Energy flow, nutrient cycling, and feeding relationships in ecosystems (p. 588) HEAT producers Energy from sunlight HEAT NUTRIENTS primary consumers detritus feeders and decomposers HEAT solar energy heat energy energy stored in chemical bonds higher-level consumers nutrients HEAT How Does Energy Flow through Ecosystems? • Energy Enters Ecosystems through Photosynthesis – After reflection, absorption, hitting a plant and making it to the chlorophyll, about 1% of the sunlight that makes it here can be used in photosynthesis. Then only about 3% of that is actually made into sugars/energy containing molecules – = 0.03% of the sunlight becomes food for the earth – Everything is either a producer or a consumer. Which are you? Which is your brother-in-law? – Figure 29.2 Photosynthesis (p. 589) Energy is captured from sunlight. Carbon dioxide is absorbed from the air. photosynthesis Water is absorbed from soil, used in photosynthesis, and stored in cells. Oxygen is released. Sugar is synthesized and used in plant tissues. plant tissues, growth Inorganic mineral nutrients (nitrate, phosphate) are absorbed from soil and used in plant tissues. How Does Energy Flow through Ecosystems? • Energy Captured by Producers Is Available to the Ecosystem – Called the biomass – Produces oxygen as a byproduct (the only thing putting oxygen in the atmosphere) – Figure 29.3 Ecosystem productivities compared (p. 590) in grams of organic material per square meter tundra (140) tropical rain forest (2200) open ocean (125) continental shelf (360) estuary (1500) coniferous forest (800) temperate deciduous forest (1200) grassland (600) desert (90) How Does Energy Flow through Ecosystems? • Energy Passes from One Trophic Level to Another – Primary consumers eat plants (herbivores –plant eaters) – Secondary consumers (carnivores- meat eaters) – A tertiary consumer is a carnivore that eats carnivores • Feeding Relationships within Ecosystems Form Chains and Webs – We can picture these levels in a more complex way… – Figure 29.4 Food chains (p. 591) – Figure 29.5 A food web in a shortgrass prairie (p. 592) TERTIARY CONSUMER (4th trophic level) PRIMARY CONSUMER (2nd trophic level) PRODUCER 1st trophic level SECONDARY CONSUMER (3rd trophic level) SECONDARY CONSUMER (3rd trophic level) Phytoplankton PRODUCER (1st trophic level) Zooplankton PRIMARY CONSUMER (2nd trophic level) TERTIARY CONSUMER (4th trophic level) How Does Energy Flow through Ecosystems? • Detritus Feeders and Decomposers Release Nutrients for Reuse – Then everything dies and decomposes – Detritus feeders – tiny animals and protists that feed on dead things – Then the fungi and bacteria break it down further to just nutrients = decomposers Passing on the energy • Energy Transfer through Trophic Levels Is Inefficient – Only 1/10th of the energy consumed by one level is available to the next level that eats it – Waste heat/energy is what keeps you warm and alive, but is lost to the environment as you live – Figure 29.6 Energy transfer and loss in a forest (p. 593) HEAT heat energy stored in chemical bonds producer primary consumer detritus feeders and decomposers secondary consumer How Does Energy Flow through Ecosystems? • Energy Pyramids Illustrate Energy Transfer between Trophic Levels – Remember 90% is lost each level (1/10th or 10% is available to the next level) – Figure 29.7 An energy pyramid for a prairie (p. 593) – Figure 29.1 The price of pollution (p. 594) tertiary consumer 1 calorie secondary consumer 10 calories 100 calories 1000 calories primary consumer producer How Do Nutrients Move within and among Ecosystems? • Remember, energy flows through (from the sun, to the Earth, is used for a bit, then goes back to space) • Carbon Cycles through the Atmosphere, Oceans, and Communities – Fossil fuels ADDS OLD carbon to the systemmaking a NEW balance in the system – Figure 29.8 The carbon cycle (p. 596) reservoir processes/locations CO2 in atmosphere trophic levels burning of fossil fuels fire respiration CO2 dissolved in ocean producers consumers wastes, dead bodies soil bacteria and detritus feeders fossil fuels limestone How Do Nutrients Move within and among Ecosystems? • The Major Reservoir for Nitrogen Is the Atmosphere – But it can’t be used by plants directly – Needs to be ‘fixed’ in the soil for root uptake – Ammonia produced by bacteria (symbiosis again!) – Figure 29.9 The nitrogen cycle (p. 597) reservoir processes/locations trophic levels/organisms electrical storms produce nitrate nitrogen in atmosphere burning produces nitrogen oxides fertilizer factories consumers producers wastes, dead bodies denitrifying bacteria uptake by plants soil bacteria and detritus feeders ammonia and nitrate in soil and water nitrogen-fixing bacteria in legume roots and soil How Do Nutrients Move within and among Ecosystems? • The Major Reservoir for Phosphorus Is Rock – Worn down through erosion – Bacteria in the soil – And the return of phosphorous from waste or dead organisms (fertilizer!) – Figure 29.10 The phosphorus cycle (p. 598) reservoir processes/locations trophic levels geological uplift phosphate in rock runoff from rivers consumers producers runoff from fertilized fields phosphate in water detritus feeders phosphate in soil phosphate in sediment How Do Nutrients Move within and among Ecosystems? • The Hydrologic Cycle does the major moving • WATER again! Very important for large scale life and us on our own. • Water Remains Unchanged During the Water Cycle – Just goes through phase changes – Figure 29.11 The hydrologic cycle (p. 599) reservoirs processes/locations water vapor in atmosphere evaporation from land and transpiration from plants evaporation from ocean Precipitation over ocean precipitation over land lakes and streams water in ocean surface runoff groundwater What Is Causing Acid Rain and Global Warming? • The earth CAN absorb some of ANY pollutant…but when we exceed the rate it can break down/take up/utilize (biotic and abiotic systems) then we have too much of a ‘normal’ substance. = Pollution. • Figure 29.12 A natural substance out of place (p. 599) • (There ARE microbes that can break down oil…just slowly.) What Is Causing Acid Rain and Global Warming? • Overloading the Nitrogen and Sulfur Cycles Causes Acid Rain – Primarily from the combustion of fossil fuels – coal is really bad unless cleaned before of after combustion – About 20 million tons of sulfur dioxide emitted in the US – Volcanoes do too, but not as consistently. – Combines with water (droplets or drops) in the atmosphere acid rain – 29.4.1.1 Reactions in the Atmosphere Form Acid Deposition • Figure 29.13 Acid deposition is corrosive (p. 600) What Is Causing Acid Rain and Global Warming? – In the Adirondack Mts. – acid levels of about 25% of the lakes is too high for fish to live – Forests harmed – Acidic water dissolves lead in old piping solder = high lead levels in your drinking water – Acid Deposition Damages Life in Lakes, Farms, and Forests • Figure 29.14 Acid deposition can destroy forests (p. 600) What Is Causing Acid Rain and Global Warming? • Disruption of the Carbon Cycle Contributes to Global Warming – Release of OLD carbon from oil/coal upsets the normal levels – Deforestation removes the things that can uptake the carbon (remember: trees etc. are just solidified atmospheric carbon dioxide!) – Greenhouse Gases Trap Heat in the Atmosphere • More like a THERMAL BLANKET than a Greenhouse, but the name has stuck. • Figure 29.15 Increases in greenhouse gas emissions contribute to global warming (p. 601) • Figure 29.16 Global warming parallels (p. 603) heat radiated into space sun outer space sunlight CO2 CFCs methane nitrous oxide atmosphere heat trapped in atmosphere volcano forest fires factories vehicle emissions houses cows average world temperature (°C) CO2 concentration (parts per million by volume) CO2 temperature The famous carbon graph Back in time… And back and back… What Is Causing Acid Rain and Global Warming? – Global Warming May Have Severe Consequences • Polar ice cap and glacier loss • Rising sea levels (NOT from ice, but from ocean EXPANSION) • Spread of tropical diseases • Change of economies/farming regions • And more? Only you can prevent… • Our Decisions Make a Difference – We are ~5% of the worlds population but produce 20% of it’s carbon dioxide – If we all switched to low power florescent light bulbs (now coming in more natural soft colors) we can reduce energy consumption – Will the leveling off of oil production and it’s increase cost change this via market pressure? • Are SUV’s as popular now as they were? Chapter 30 • Earth’s Diverse Ecosystems What Factors Influence Earth’s Climate? • Both Climate and Weather Are Driven by the Sun – What causes the seasons? – We are close to the sun at one time of the year and further from the sun at anther time. – Which times of the year are we closest or further? The reason for the season – We are closest to the sun Jan 5th – We are further from the sun July 11th (give or take a few days) – IT IS NOT THE SUN EARTH DISTANCE!! So what is it? What Factors Influence Earth’s Climate? • Sunlight Strikes Earth at Various Angles – Gives us the seasons AND the hottest time of the day and coolest time of the night – Figure 30.1 Earth’s curvature and tilt produce seasons and climate (p. 610) sunlight sunlight The Earth at 23.5O Tilt Seasonal Variation. What Factors Influence Earth’s Climate? • Air Currents Produce Regional Climates – Figure 30.2 Distribution of air currents and climatic regions (p. 612) Air Mass Formation General Air Patterns Atmospheric Circulation Pattern The sun, through heating of land and air, drives the earth’s patterns of rains, winds, and ocean currents. Air on the move Coriolis Effect Cell Names… http://goes-rap.cira.colostate.edu/GOES-10/GEMS/Original/JPEG/Current/fulldisk_c01.jpg Global Patterns of Air Circulation/Precipitation • Air rises at the equator (equator = hot) First convection cell is highest because most energy • Adiabatic cooling • Rain occurs (cool air holds less water). • Air from the North and South comes in to replace it. • Coriolis effect - air is deflected because of momentum. Air Pressures Areas of High and Low Pressure Generate Surface Winds cold, dry air falls rain forest cool, moist air rises (rain) 60º N warm, dry air falls 30º N desert rain forest 0º hot, moist air rises (rain) desert 30º S warm, dry air falls 60º S cold, dry air falls cool, moist air rises (rain) South African Desert Sahara Desert Arabian Desert Coriolis Effect Coriolis Effect Responsible for where wind blows from; wind patterns influence regional weather. Winds Wind is the horizontal movement of air from areas of high to low pressure. High pressure regions are dominated by cold, descending air, while low pressure areas are associated with warm, rising air masses. Winds blow from high pressure to low pressure. Winds are deflected from their course by the Coriolis Effect (to the right in the Northern Hemisphere) Ocean Currents Due to Coriolis Effect and Land Masses Ocean waters warmed in the equatorial regions transport heat energy to other parts of the globe. Circulation of Warm and Cool Ocean Waters has a Moderating Effect on Coastal Cities Effects of Upwelling and Downwelling on Currents When the wind blows parallel to a Northern Hemisphere coastline and the ocean is to the right of the wind direction, upwelling can result. Wind in the opposite direction produces downwelling. Upwellings Bring Nutrients to Surface ENSO (El Niño – Southern Oscillation) The Southern oscillation is a phenomenon that refers to the see-saw effect of surface air pressures in the Eastern and Western Pacific Ocean. For Example, when air pressure recordings are high in Tahiti, they are low in Eastern Australia. Also noted was a cycle of varying Pacific Ocean temperatures which occurs annually on a small scale. This was recognized by Peruvian fishermen who called it El Niño (Christ Child) because it occurred during the winter close to Christmas. Normally, have warm waters and heavy precipitation in the western Pacific. El Niño, have warm waters migrate to the eastern Pacific along with the convective cell and increased rainfall. El Niño and La Niña La Niña (cold conditions) Normal Conditions El Niño (warm conditions) Climate Changes Associated with ENSO (El Nino in the media) http://proa.accuweather.com/www/phoenix2/includes/professional/misc/misc-sst.htm 30.1 What Factors Influence Earth’s Climate? • 30.1.4 Ocean Currents Moderate Nearshore Climates – Figure 30.3 Ocean circulation patterns (p. 612) Greenland Eurasia Eurasia North America Africa South America Australia Antarctica Antarctica What Factors Influence Earth’s Climate? • Continents and Mountains Complicate Weather and Climate – Figure 30.4 Effects of elevation on temperature (p. 613) – Figure 30.5 The rain shadow of the Sierra Nevada (p. 613) rock, snow, and ice tundra coniferous forest deciduous forest tropical forest equatorial regions Latitude polar regions average annual precipitation (cm) altitude (m) winds west Where do you find places like this in the US? east What Conditions Does Life Require? • Nutrients from which to construct living tissue • Energy to power that constuction • Liquid water in which metabolic reactions can take place • Appropriate Temperatures • What about mushrooms? • Figure 30.6 Environmental demands mold physical characteristics (p. 614) – nearly identical but widely separated evolutionary areas… How Is Life on Land Distributed? • Terrestrial Biomes Have Characteristic Plant Communities – Biomes are the regions with similar temperature, nutrient supply, etc. – Biomes are typically named by the major type of vegetation found there – Figure 30.7 The distribution of biomes (p. 614) – Figure 30.8 Rainfall and temperature influence biome distribution (p. 615) 60º N 30º N 0º (equator) 30º S 60º S tropical forest chaparral grassland desert temperate deciduous forest coniferous forest savanna and tropical shrub forest temperate rain forest tundra and alpine vegetation ice low Temperature tundra coniferous forest (taiga) cool desert high warm desert low cool grassland warm grassland temperate rain forest temperate deciduous forest savanna Rainfall tropical deciduous forest tropical rain forest high A quick survey… How Is Life on Land Distributed? • Tropical Rain Forests – Temperatures 77 to 86F; little seasonal variation – 100-160 inches of rain a year! – Highest biodiversity on the planet • Picture of Tropical rain forests (p. 616) • Figure 30.9 The tropical rainforest biome (p. 616) • Human Impact: Deforestation… • Figure 30.10 Fire engulfs a tropical rain forest in Brazil (p. 617) How Is Life on Land Distributed? • Tropical Deciduous Forests – Slightly further from the equator – A definite wet and dry season – Plants usually drop their leaves in the dry season to conserve water • Tropical deciduous forests (p. 618) How Is Life on Land Distributed? • Savannas – Moving away from tropical deciduous forests, trees get more sparse – Rainy season with 12 inches/year or less • Figure 30.11 The African savanna (p. 618) • Human impact: poachers • Figure 30.12 Poaching threatens African wildlife (p. 618) How Is Life on Land Distributed? • Deserts – Usually at about 30 degrees N and S of the equator – Less than 10 inches of annual rainfall – Often hot, but can be very cold » The Gobi Desert in Asia = temperature below freezing for half the year – Plants adapted to harsh low water environment • Human Impact – off road damage to delicate life Web • Figure 30.13 The desert biome (p. 619) • Figure 30.14 The Sonoran Desert (p. 619) How Is Life on Land Distributed? • Chaparral – – – – Coastal regions that border deserts Vegetation called chaparral Annual rainfall as much as 30 inches Wet winters, hot dry summers • Figure 30.15 The chaparral biome (p. 620) How Is Life on Land Distributed? • Grasslands – – – – • • • • Located in the center of continents 10-30 inches of rain typically Warm/hot summers, cold winters Fires are important to life cycles Human impact: Grazing and Farming Figure 30.16 Tallgrass prairie (p. 620) Figure 30.17 Shortgrass prairie (p. 621) Figure 30.18 Sagebrush desert or shortgrass prairie? (p. 621) How Is Life on Land Distributed? • Temperate Deciduous Forests – More precipitation than grasslands – 30-60 inches a year – Cold winters! – Trees drop leaves during cold weather. – Many insects and arthropods to feed on biomass • Human Impact: Hunting of predators/deer etc. • Figure 30.19 The temperate deciduous forest biome (p. 622) How Is Life on Land Distributed? • Temperate Rain Forests – – – – – Mountains on the western (upwind) side of continents Up to 160 inches of rain a year Mild temperatures year round No need to shed leaves Fog is common • Figure 30.20 The temperate rainforest biome (p. 623) How Is Life on Land Distributed? • Taiga – – – – – North of grasslands and temperate forests Also called northern coniferous forest Slow growth trees – conifers Harsh cold winters Large game, bear, moose, caribou etc. • Human Impact: The lumber industry • Figure 30.21 The taiga (or northern coniferous forest) biome (p. 624) • Figure 30.22 Clear-cutting (p. 624) How Is Life on Land Distributed? • Tundra – – – – – The last biome before the polar ice cap Winters often reach –40F or below Strong winds Average less 10 inches a year freezing deserts Permafrost = permanently frozen soil usually about 1.5 feet below the surface – Roots limited to a shallow soil layer – Short growing season • Human impact: Any human changes last for centuries, little grown to erase scars. • Figure 30.23 The tundra biome (p. 625) How Is Life in Water Distributed? • Freshwater Lakes Have Distinct Regions of Life – Life Zones Are Determined by Light and Nutrients • Littoral zone = shallows, plants can anchor, lots of sunlight and nutrients • Limnetic zone = Enough light penetrates to allow some photosynthesis • Profundal zone = No light, dead stuff falls to feed bottom dwellers • Figure 30.24 Life zones of a lake (p. 628) – Freshwater Lakes Are Classified by Nutrient Content littoral zone limnetic zone profundal zone How Is Life in Water Distributed? • Marine Ecosystems Cover Much of Earth – Photic zone = depth sunlight penetrates to support photosynthesis – Aphotic zone = too dark for direct production of energy from sunlight – Upwelling is needed to bring nutrients from the deep to fish and creatures in shallow (warmer) water – Figure 30.25 Ocean life zones (p. 630) intertidal zone near-shore zone dry land open ocean photic zone 200 m aphotic zone How Is Life in Water Distributed? – Coastal Waters • • • • • Support a LOT of life Nutrients are available Tides move nutrients and oxygen around Salt marshes and estuaries protect the shore in storms and provide for much life • Human Impact: Hotels, recreation, oil spills etc. • Figure 30.26 Nearshore ecosystems (p. 631) How Is Life in Water Distributed? – – – – Coral Reefs Water about 72-82F In the photic zone – less than 130 feet deep Build up from carbon fixed in carbonate shells over long periods of time – Wide diversity of life – Human Impacts: Over fishing, river pollution, many are getting ‘sick’ presently • Figure 30.27 Coral reefs (p. 632) How Is Life in Water Distributed? – The Open Ocean - about 65% of the planet – Food Web depends on phytoplankton • Things that swim (surface is far far below, outside of the reach of sunlight) • A strange variety of deep see creatures – much to be discovered • Human Impact: Over fishing (whales etc.) and pollution. • Figure 30.28 The open ocean (p. 634) How Is Life in Water Distributed? – Hydrothermal Vents • Discovered in 1977 • Superheated volcanically warmed water rises from the ocean floor • Supports a wide variety of life – blind, no photosynthesis, sulfur and other chemical reactions power life • Some can survive in water up to ~250F! • Figure 30.29 Hydrothermal vent communities (p. 635) Finis! • You’ve now been from atoms to life across the planet and through time.