Ecosystems

Key terms• Autotrophs/Producers• Heterotrophs/Consumers• Decomposers• Ecological Community• Community-level interactions• Keystone species• Trophic level• Limiting Factors• Know the difference and be able to compare:

• Biotic factors vs. Abiotic factors• Food chains vs. Food webs• Niche vs. habitat

StructureLearning Objectives/questions:

• What defines an ecosystem?

• How to classify and explain the interactions w/in an ecosystem.

Structure• Levels of Ecological Organization:

• Atom• Molecule• Cell• Organism• Population• Community• Ecosystem• Biosphere

electron

neutron

proton

Life on Earth• Life on earth depends on 3 interconnecting factors:

1. The one-way flow of energy (high-quality)o Sun to earth and living thingso Photosynthesis (low – energy)o Can not be recycled

2. Cycling of matter or nutrients (round – trip)o Only certain amount of matter and nutrients on

earth. Required for life sustainabilityo Depending on the cycle, takes seconds to centuries.

3. Gravityo Allows us to hold onto the atmosphere surround the

earth, which allows life to be sustained.

Abiotic FactorsNon-living components:• Water, air, nutrients• Rocks • heat, solar energy• Salinity• Temperature• pH• Wind

Biotic FactorsAll components that consists of living and once lived.• Plants• Animals• Microbes• Dead organisms and parts of organisms• Waste products from organisms

Ecology• Ecology – study of relationships in the natural world.• Ecologist – the person or scientist that study these interactions• Applied ecology – Uses information from ecologists to better understand issues like developing effective vaccination strategies, managing fisheries or large ranches without over harvesting, depleting genetic diversity, designing land/marine conservation reserves for threatened and endangered species (spp) and modeling how ecosystems may respond to global climate change, natural and human disasters.

Biomes• A collection of ecosystems that share similar climatic conditions, vegetation and animals.

In relation to ecosystems• Most changes in ecosystems are caused by climate change, species movement in and out of the ecosystem and ecological succession.

• Species basic physical conditions for survival also play a role in an ecosystem.

• Geography has an important impact on ecosystem changes because of climate circulation patterns (atmospheric and oceanic) and climate zones.• Factors include:

•Temperature ranges, moisture availability, light and nutrient availability, and altitude (height above or below sea level).

BiomesClimate Zones:• Divided into 4 distinct areas -

• Tropics – warmest, wettest regions• Equator - where the sun’s heat and energy are the strongest.• Subtropics – high-pressure creates dry zones @ 30° latitude

North and South.• Poles – Driest and coldest zones @ 60° latitude.

• Reason for climate zones – • The angle of impact of the sun’s rays on the earth

• Equator = 90° Angle• Latitude and altitude change the ambient heat energy the

further you move away from the equator or away from the surface.

• The Earth is tilted at a 23.5° angle creating seasons as it orbits around the sun.

Biomesbroad geographical areas that stretch the globe which contain many ecosystems with a wide range of diverse groups of organisms that are adapted for those specific temperatures and precipitations.

Division of biomes (with subdivisions)Aquatic

Freshwater – swamp forests, lakes, ponds, streams, rivers and bogs

Marine – rocky shore, mud flats, coral reefs, mangrove swamps, continental shelf, deep ocean

TerrestrialDeserts – hot and coldForests – Tropical, temperate, and boreal(taiga)Grasslands – Tropical or savanna and temperateTundra – arctic and alpine

BiomesAquatic Biomes (Freshwater and Marine)• Covers ¾ of the earth’s surface.• Include – open ocean, coral reefs, estuaries, lakes, rivers• Large bodies (oceans & lakes) are layered• Surface – warmest with most amount of light filtration.• Depends on the movement and mixture from deep to surface for nutrients.

Biomes - AquaticWetlands – Freshwater and saltwater swamps, marshes, bogs

•All have standing water, water table is at the surface, ground is saturated• Little oxygen creates special soils and decay takes place slowly.•Creates the coal we use today over a geological time period.

•Bogs – no surface water but have a layer of vegetation that lays on top of the water.•Bacteria found here carry out chemical processes that produce methane and hydrogen sulfide.

Biome - AquaticFreshwater – lakes, rivers, ponds, streams, groundwater.

•Very small portion of the Earth’s water supply.•Used to supply water to homes, industry, recreation, and agriculture.•Rivers and streams are used to transport materials from land to ocean.•Abundant in biotic factors.•Estuaries – mouths of rivers where ocean water and freshwater mix. – rich in nutrients, impt. in breeding sites for fish (salmon).

Biome - AquaticIntertidal zones:

•Areas exposed to the alternation of air during low tide and ocean waters during high tide.•Constant movement of water transports nutrients in and out of the zone.•Major economic resources found here, i.e. seafood•Susceptible to pollution from land and freshwater sources.•Extreme variations in environmental conditions occur here.

Biome - AquaticOpen Ocean:

•Called pelagic region• Tend to be low in nitrogen and phosphorus •Benthos – bottom portion

• Primary food source is dead organic material that falls from above.•Upwellings – Deep ocean waters

• Cold and dark, life is scarce• Rich in nutrients – dead organic material (organisms) fall from surface• Upward flows of waters brings those nutrients to the surface allowing abundant growth of algae and animals at the surface.• Commercial fishing occurs in these areas because of the abundant and diverse fertile organisms found here.

•Hydrothermal vents – occur in deep ocean where plate tectonic processes create vents of hot water with a high concentration of sulfur compounds.

• Chemosynthetic organisms live here• Water pressure is high, and temps range from boiling to frigid.

Differences

OceansFreshwat

erLarge continuous areas Varies in size, mostly isolated

from other water sources.

Organisms have a more free range of movement through areas, Less need to adapt to changes in conditions

More adept to a wider range of changing conditions and able to change habitats.

Biomes - TerrestrialTundra – treeless plains that occur in the harsh climates of low rainfall and low average temps.

•Dominant vegetation – grasses, mosses, lichens, flowering dwarf shrubs•Two types

•Arctic – High latitudes, Antarctica and N. Canada/Greenland•Alpine – High elevation, Himalayas, Rocky Mountain Ranges, Swiss Alps• They differ by the types of animals found

•Permafrost – permanently frozen ground, extremely fragile

Biomes - TerrestrialBoreal (Taiga) Forests:

•Forests of cold climates•High latitude and High •Dominated by conifers (trees), form dense small trees.

• Spruce, firs, pines, aspens and birch to name a few.•Biological diversity is low•Commercially valuable resources• Include large mammals, small rodents, many insects, birds, raptors•Contain some of the Earth’s largest remaining wilderness•Conservation is important (Yellowstone)

Biomes - TerrestrialTemperate Deciduous Forests:

•Climates are somewhat warmer than Boreal.•N. America, Eurasia, Japan•Dominant vegetation

• Maples, beech, oaks, hickory, chestnuts• Taller trees than Boreal

•Dominant animals• Smaller mammals that tend to live in trees (squirrels), birds, rodents, insects• Larger mammals tend to live in the younger forests where tree population is smaller

• Long dominated by humans • Important nature preserves (Yellowstone, Yosemite) • Very few remaining uncut, old growth forests left

•Fire is natural and recurring, but not as dominant as in Boreal

Biome - TerrestrialTemperate Rain Forests:

•Temps are moderate and precipitation exceeds 250cm/year•Rare but spectacular•Dominant vegetation –

• Coniferous and evergreen trees• Redwood, Sequoia, Douglas Fir, Western Cedars

•Northern Hemisphere – • California, Oregon (Redwood, Sequoia)• Canada

•Southern Hemisphere – • New Zealand

•Major source of Timber crops, esp. in N. America• Low diversity of plant and animal species because of the low sunlight available on the forest floor.

Biome - TerrestrialTemperate Woodlands:

•Temp patterns are like deciduous forests, but climate is slightly drier.•N. Hemisphere –

•New England, Georgia, Caribbean islands.•Dominant veg –

• Samll trees – pinion pine, evergreen oaks, ponderosa pine• Stands are open and wide allowing plenty of sunlight to reach forest floors

•Fast growing and used for timber crops•Animal species –

•Deer, small/med mammals, birds, rodents

Biome - TerrestrialTemperate Shrublands:

•Mediterranean climates, low rain fall and cool seasons, Drier climates called Chaparral

•Coastal California (mid to lower), Chile, S. Africa, Med region of Europe (Ancient Greece and Rome).

•Miniature woodlands with dominant shrubs•Highly modified by humans because of the climate and is conducive for ranching and farming.•Young tree/shrub lands – conducive to fires•Used to decorate many streets and gardens

Biome - TerrestrialTemperate Grasslands:

•Too dry for forests, too moist for deserts.•Dominant plants –

•Grasses and flowers•Soils have a deep organic layer, perfect for farming

• i.e. – Midwest, Kansas, Wyoming•Covers areas from Canada down to Northern Oklahoma. •Abundant animal species

• Large mammals – horses, American Bison, Kangaroos (Australia), antelope and other large herbivores (Africa)• Small mammals – rodents (prairie dogs), foxes

Biome - TerrestrialTropical Rain Forests:

•Avg temp is high and relatively constant the whole year, rainfall avg is high and frequent.•Northern South America, Central America, Western Africa, N. Australia, Indonesia, Philippines, Borneo, Hawaii and parts of Malaysia.•Diverse plant and animal species –

•Approx 2/3 of all flowering plants live here.•Mammals tend to live in trees – Monkeys, sloths, etc.•High diversity of bird species and insect species

Biome – TerrestrialTropical Seasonal Forests and Savannas:

•Low latitudes, avg temp is high and constant•Rainfall is abundant but seasonal•Location –

• India, SE Asia, Africa and N & S Americas.•Savannas – grasslands with scattered trees•Large mammals – Lions, Tigers, Herds like Zebras, Giraffes, Pandas, Elephants, etc.•Abundance of plant species.

Biome – TerrestrialDeserts:

•Driest regions where vegetation can survive.•Rainfall is typically less than 50cm a year.•Sahara (Africa), Mojave (Ca/Az), Whitesands (N.M), Mexico and Australia occur at low latitudes.•Cold deserts – Utah, Nevada and W Asia•Specialized vegetation

• Joshua tree in Ca/Az.• Cacti• yuccas, • turpentine bush• prickly pears, • false mesquite, • agaves and brittlebush.

•Specialized animal species• Vertebrate – lizards, snakes, jackrabbits, foxes, rodents, burrowing animals, birds, kangaroo mice• Invertebrates – insects, beetles, arachnids

Food Webs and Food Chains•Food webs:

• shows the complexity of relationships and energy flow between organisms within an ecosystem.

•Food Chains:•Shows a simple one-way relationship and energy flow between a set group of organisms.

Arrows represent the way the energy flows through a system. (eaten to eater)

Examples:Food chain –

Grass grasshopper sparrow Fox Cougar

• Food Web

Cougar

Fox Deertree sparrow

grasshopper worm

flower butterfly

vole grass

• Tertiary consumer

• Secondary consumer 2

• Secondary consumer 1

• Primary consumer

• Producer

Pyramids of Ecosystems• Trophic level pyramid: