Community Interactions

Relationships Between Organisms

•

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

Keystone Species

: – A species of great importance to a community – If it’s population changes it can cause dramatic changes to structure of community

– Ex: • Sea Otters off Pacific Coast of North America – Links to Sea urchins, kelp and many other species – http://www.youtube.com/watch?v=eYpM qDNKzs&safe=active

• Beavers (a keystone species) http://www.youtube.com/watch?v=kZVbKwDmr-o&safe=active

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?v=nRkWz LzCi2U&safe=active

Mutualism

: – Both species benefit Ex: • Clown Fish and Sea Anemone • Ants and aphids • “Cleaning Stations” (Rhino and “Tick Bird”)

• 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?v=CiBAq2a6qjQ&safe=active

• • Ant and Butterfly Symbiosis: http://video.nationalgeographic.com/video/ animals/bugs-animals/ants-and termites/ant_caterpillarsymbiosis/ • • Goby and Shrimp http://www.youtube.com/watch?v=dKuWlB jUFo8&safe=active

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

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)

• Check out this Crazy Fungal Parasite!

• Cordyceps: http://www.youtube.com/watch?v=XuKjBIBBAL8&safe=a ctive • • Body Invaders: http://www.youtube.com/watch?v=vMG LWyNcAs&safe=active

• • Symbiotic Relationships: http://www.youtube.com/watch?v=zSmL2F 1t81Q&safe=active

Ecological Succession

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

Islands of Hawaii

• How did they become a tropical paradise?

• Started off as volcanic rock.

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

Soil Formation

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

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_id=182733

• 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

Primary Succession

How Long Does it Take?

Note: Animal life will also change with the succession of plants Ex: grass eaters – shrub dwellers – tree livers

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?v=iZA5yfrzLV8&safe=active

• 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

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?v=C2ZRe_kIRdA&safe=active

• Pine Barrens Fire

Note: some species require catastrophe to reproduce Ex: Certain pine cones will only release seeds if heated by fire

Secondary Succession Can Happen Here Soil is Established

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

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

Biomes of the Earth

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

• 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 Earth’s axis and amount of sunlight over course of the day

• 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

Types of Terrestrial Biomes

Tundra

http://education portal.com/academy/lesson/biomes tundra-taiga-temperate-grassland and-coastlines.html

•

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)

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)

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

Taiga

http://dsc.discovery.com/tv-shows/other-shows/videos/assignment-discovery-shorts-iii-biomes-taiga.htm

•

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

Taiga

•

Vegetation:

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

Taiga

•

Animals

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

Deserts

•

Characteristics:

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

•

Vegetation

: • Special adaptations to conserve water

Deserts

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

•

Animals:

• Many active at night, sleep during day due to heat

Deserts

• Adaptations to conserve water and radiate excess heat • Fennec, snakes, lizards, spiders, scorpions, foxes, coyotes, hawks, owls, kangaroo rat http://www.youtube.com/watch?v=7Ifk9IJl0A0&safe=active

Temperate Deciduous Forests

•

Characteristics

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

Temperate Deciduous Forests

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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

Temperate Deciduous Forests

•

Animals

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

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?v=msdY-JJilzM&safe=active

Grasslands

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Vegetation

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

Grasslands

•

Animals

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

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

Tropical Rain Forest

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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

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

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

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 Earth’s temp.

– Temperature very stable, changes less during the day than on land

•

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

•

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

•

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