Community Interactions

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Community Interactions

• Relationships Between Organisms

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• Predator-Prey Relationships
• Predators can affect the size of prey populations
  in a community and determine the places prey can
  live and feed
• Ex Fox and rabbit populations

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• Herbivore-Plant Relationships
• Herbivores can affect both the size and
  distribution of plant populations in a community
  and determine the places certain plants can
  survive and grow
• Ex White tailed deer and food plants

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• Keystone Species
• A species of great importance to a community
• If its population changes it can cause dramatic
  changes to structure of community

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• Ex
• Sea Otters off Pacific Coast of North America
• Links to Sea urchins, kelp and many other species
• http//www.youtube.com/watch?veYpM-qDNKzssafeac
  tive

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• Beavers (a keystone species)

http//www.youtube.com/watch?vkZVbKwDmr-osafea
ctive
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Symbiotic Relationships

• Organisms live in close association with each
  other and at least one benefits.
• Relationships that help one or both species to
  survive
• Symbiotic Relationships
• http//www.youtube.com/watch?vnRkWzLzCi2Usafeac
  tive

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• Mutualism
• Both species benefit
• Ex
• Clown Fish and Sea Anemone
• Ants and aphids
• Cleaning Stations (Rhino and Tick Bird)

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• Ex Protozoa in digestive tracts of termites
• Termites have cellulose digesting microorganisms
  in their digestive tract
• Provide food and a place to live
• Termites could not get nutrients from wood
  without them.

http//www.youtube.com/watch?vCiBAq2a6qjQsafeac
tive
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• Ant and Butterfly Symbiosis
• http//video.nationalgeographic.com/video/animals/
  bugs-animals/ants-and-termites/ant_caterpillarsymb
  iosis/
• Goby and Shrimp
• http//www.youtube.com/watch?vdKuWlBjUFo8safeac
  tive

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• Commensalism
• One species benefits, the other species is
  neither harmed nor benefitted
• Ex Remora and pilot fish and shark
• Eats scraps from sharks meal
• Barnacle and whale
• Whale travels about, allowing them to get a
  constantly new supply of food

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• Parasitism
• One organism benefits and the other is harmed
• Generally parasites weaken, but do not kill the
  host
• EX
• Tapeworms in digestive tract
• Mistletoe plant sends roots into host plant and
  absorbs water, minerals and nutrients
• Cowbird (brood parasite)
• Leeches, Ticks, Fleas, Lice (feed on blood and
  skin of animals)

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• Check out this Crazy Fungal Parasite!
• Cordyceps http//www.youtube.com/watch?vXuKjBIBB
  AL8safeactive
• Body Invaders
• http//www.youtube.com/watch?vvMG-LWyNcAssafeac
  tive

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• Symbiotic Relationships
• http//www.youtube.com/watch?vzSmL2F1t81Qsafeac
  tive

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Ecological Succession
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Succession in Communities

• Changes that take place to communities over time
  (especially after disturbances).
• Living organisms alter their environment making
  it more suitable for some, less suitable for
  others
• Original organisms slowly replaced by others
  until climax community is reached
• Takes decades or even centuries to develop

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Islands of Hawaii

• How did they become a tropical paradise?
• Started off as volcanic rock.

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Primary Succession

• Colonization of new sites (lifeless areas)
• Bare rock, new volcanic islands, sand, stream
  bank (no organic material present)
• Slow process
• Begins with soil formation

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• Soil Formation
• Starts with rocks
• Erosion by wind/rain causes pieces to break off
• Freezing/thawing of water causes cracks to form

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• Pioneer Organisms
• first organisms to colonize barren areas
• Ex
• Lichens (mutualistic symbiosis between
  fungus/algae)
• Cling to rocks, secrete acids that help break
  down rock
• When they die, they add layer of organic material
  that starts soil formation

http//teachertube.com/viewVideo.php?video_id1827
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• Plants like mosses now can grow in the thin layer
  of soil
• When they die out the soil layer gets thicker and
  thicker eventually allowing plants with deeper
  and deeper roots to thrive.
• Eventually a climax community develops

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Primary Succession
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How Long Does it Take?
Note Animal life will also change with the
succession of plants Ex grass eaters shrub
dwellers tree livers
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• Climax Community
• Community at the end of line of succession that
  is mature and stable
• Described in terms of dominant plant forms
• Type of climax community depends on the physical
  factors in environment
• Ex
• Good soil/good rainfall forest community
• Good soil/less rainfall grassland community
• Climax Communities
• http//www.youtube.com/watch?viZA5yfrzLV8safeac
  tive

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• Examples of Climax Communities
• Sphagnum Bog shallow lake/pond, peat moss
• Mangrove Swamp muddy tidal flat, mangrove trees
• Pine Barrens sandy peat soil, pine trees

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Secondary Succession

• Occurs in an area where the climax community has
  been destroyed
• However, SOIL IS STILL THERE!
• Occurs at a faster rate, soil is already present.
• Ex
• Forest fire, flood, volcanic explosion, human
  development
• Succession after Fire
• http//www.youtube.com/watch?vC2ZRe_kIRdAsafeac
  tive

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• Pine Barrens Fire

Note some species require catastrophe to
reproduce Ex Certain pine cones will only
release seeds if heated by fire
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Secondary Succession Can Happen Here Soil is
Established
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• Succession in Lakes and Ponds
• Sediment, fallen leaves, debris gradually
  accumulate on the lake bottom
• Plants take root in the shallower water along
  edge
• Pond eventually becomes a marsh
• Eventually fills up becoming dry land

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• Succession Summary
• http//education-portal.com/academy/lesson/ecologi
  cal-succession-from-pioneer-to-climax-communities.
  html

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Biomes of the Earth
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• Biomes large geographical regions
• characterized by a particular type of climax
• community
• Have similar
• temperature range
• annual precipitation
• sun exposure
• type of soil
• type of plants and animals

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• Temperature Differences
• Not all parts of the earth get the same amount of
  sunlight
• Five times stronger at equator than at the poles
• Seasons change due to tilt of Earths axis and
  amount of sunlight over course of the day

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• Topography
• Mountain ranges can affect rainfall patterns from
  one side of mountain to another
• Can often see changes in plant communities with
  increasing altitude as temperature changes

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Types of Terrestrial Biomes
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Tundra
http//education-portal.com/academy/lesson/biomes-
tundra-taiga-temperate-grassland-and-coastlines.ht
ml

• Characteristics
• Low average temp, short growing season
• Long cold winters where ground is completely
  frozen
• Only thin top layer thaws in summer, rest is
  permafrost
• Average precipitation 10-12cm per year (mostly
  snow)

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Tundra

• Vegetation
• lichens, moss, grasses, sedges, shrubs
• Almost no trees due to permafrost and short
  growing season
• Nutrient poor soil due to slow rate of
  decomposition (nutrients recycled slowly)

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Tundra

• Animals
• Reindeer, mush oxen, caribou, wolves, arctic
  hares, arctic foxes, lemmings, snowy owls
• During warm season a lot of insects like flies
  and mosquitoes bring birds, ducks, geese to nest
  and breed in safety because of relative absence
  of certain predators

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Taiga
http//dsc.discovery.com/tv-shows/other-shows/vid
eos/assignment-discovery-shorts-iii-biomes-taiga.h
tm

• Characteristics
• Cold severe winters, short mild summers
• Ground thaws completely in summer (no
  permafrost), so can support tree growth
• Precipitation 35-40cm a year with a lot of fog

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Taiga

• Vegetation
• Mostly coniferous pines, firs, spruce
  (evergreens)
• Soil often acidic due to pine needles

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Taiga

• Animals
• Moose, wolves, bears, lynx, deer, elk,
  wolverines, martens, snow shoe hares, porcupines,
  rodents, birds, insects

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Deserts

• Characteristics
• Driest biome
• Sandy soil, nutrient poor
• Rainfall less than 25 cm per year (arid)
• Temp. varies widely during day

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Deserts

• Vegetation
• Special adaptations to conserve water
• Widespread shallow roots to get maximum water
  when available
• Cactus, yucca, mesquite trees, sagebrush,
  creosote bushes

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Deserts

• Animals
• Many active at night, sleep during day due to
  heat
• Adaptations to conserve water and radiate excess
  heat
• Fennec, snakes, lizards, spiders, scorpions,
  foxes, coyotes, hawks, owls, kangaroo rat

http//www.youtube.com/watch?v7Ifk9IJl0A0safeac
tive
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Temperate Deciduous Forests

• Characteristics
• Cold winters, hot and humid summers
• Growing season about 6 months of year
• Rainfall 75-150cm per year

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Temperate Deciduous Forests

• Vegetation
• Soil thick top layer of humus
• Mostly deciduous trees
• Period of plant dormancy during winter (lose
  leaves)
• Oak, maple, hickory, beech, chestnut, birch,
  shrubs, herbaceous plants, ferns and mosses

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Temperate Deciduous Forests

• Animals
• Many hibernate during winter
• Wolf, fox, bobcat, deer, raccoon, squirrel,
  chipmunk, rabbits, salamanders, birds (many
  migrate during winter)

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Grasslands

• Characteristics
• Prairies, steppes, pampas, savannah
• Occurs in both temperate and tropical climates
• Rainfalls is 25-75cm per year (usually with dry
  season)
• Soil deep and rich, (good farmland)

• http//www.youtube.com/watch?vmsdY-JJilzMsafeac
  tive

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Grasslands

• Vegetation
• Many species of grass (rye, oat, wheat) and wild
  flowers
• Where more water present, shrubs and some trees
  may develop.

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Grasslands

• Animals
• North America coyote,rattlesnake, prairie dog,
  jack rabbit, bison, pheasant, prairie chicken,
  hawk, owl
• Africa zebras, giraffes, gazelles, lions,
  elephants

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Tropical Rain Forests

• Characteristics
• Most biologically diverse ecosystem
• Greatest number of species per unit area
• Uniform warm wet climate through year
• Constant rainfall 200-400cm per year

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Tropical Rain Forest

• Vegetation
• Broad leaved plants, most do not lose leaves
• Little light hits lower canopy
• Only shade tolerant trees, vines and shrubs, grow
  below tall trees
• Little organic material in soil (poor farmland)
• Organic materials decay quickly and recycle back
  into living plants

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Tropical Rain Forest

• Animals
• Wide variety, many are adapted to live at a
  particular level of the canopy
• Monkeys, bats, parrots, snakes, lizards, tapirs,
  insects

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Aquatic Ecosystems

• Major Abiotic Factors
• Water depth
• Photic Zone sunlight can reach it,
  photosynthesis can occur
• Aphotic Zone deeper water, photosynthesis cannot
  occur
• Amount of dissolve gasses and nutrients
• Oxygen and Carbon Dioxide, Nitrogen, Phosphorus

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Aquatic Ecosystems

• Marine Biomes (saltwater oceans)
• Largest most stable biome (70 of earths surface)
  
• Most photosynthesis on Earth is done here by
  algae near ocean surface
• Oceans absorbs and hold large quantities of heat
  and help to regulate Earths temp.
• Temperature very stable, changes less during the
  day than on land

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• Marine Animals
• Ocean floor (benthic life) Sponges, corals,
  barnacles, anemones, starfish, clams, snails,
  crabs
• Free Swimming squid, fish, turtles, seals,
  whales

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• Plankton float near surface and are carried by
  currents
• Phytoplankton Photosynthetic producers
• Zooplankton Consumers
• Form basis of food web for whole marine ecosystem

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• Zones of the Oceans
• Intertidal Zone
• High tide submerged
• Low Tide exposed to air sunlight
• Coastal Ocean (Littoral Zone)
• Shallow, slopes to open ocean
• Contains nutrients carried into ocean by rivers
  and streams
• Open Ocean
• Deep water, photic aphotic zones
• Most photosynthesis happens here
• Deep Ocean
• No sunlight, under high pressures
• Food webs based on dead organisms that fall from
  above or on chemosynthetic organisms

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• Estuaries
• Saltwater meets freshwater (where river meets the
  sea)
• Excellent nurseries to raise young aquatic
  wildlife (offers protection)

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• Freshwater Biomes
• Ponds, lakes, streams, rivers, wetlands (swamps
  and bogs)
• Provide most land animals with fresh drinking
  water
• Many be nutrient rich or poor depending on amount
  of sediment