Download Community Interactions – several species living together!

Ch. 4
COMMUNITY INTERACTIONS –
SEVERAL SPECIES LIVING
TOGETHER!
What determines world
climate? Sunlight and
precip!
Niche  A range of conditions in which a species lives,
survives in and hopefully reproduces.
Competitive Exclusion
Principle:
 Species partition
 Resources so they
 Are not competing
 Against each other
 And all can survive!
Symbiosis – Any relationship
where 2 species live closely
together.
 There are 3 main classes:
 Mutualism +/+ Both benefit
 Commensalism + / 0 One benefits, the other is
neither helped nor harmed.
 Parasitism +/- One benefits while the other is
harmed.
 Look at the following photos and write M, C or P
for each relationship:
A squirrel living in an oak:
Cleaner wrasse and eel:
Ramora and shark:
Flea and dog:
Bee pollinating flower:
Bromeliad on tree:(epiphyte)
Sea lamprey and fish:
Blind shrimp and Gobi:
Tomato hornworm and wasp pupa:
Barnacle and whale:
Acacia tree and ants:
Clown fish and anenome:
Tapeworm and human:
Cattle egret and water
buffalo:
This crustacean devours the
fish tongue and takes its’
place.
Greenland shark and copepod:
Toxoplasma in rats/cats:
http://v.youku.com/v_show/id_X
Mjk1OTYxMTg0.html
Succession – over time,
ecosystems change

Primary – a land ecosystem that has been destroyed to the point that not
even soil remains. Ex: glaciers, volcanoes

Pioneer species come in first (lichens, fungi) to break up rock and create soil.
Soon plants can get a foothold and the area changes as soil nutrients build
up - plants bring ani mals and decomposers etc…
Secondary Succession:
 An ecosystem is disturbed, but soil remains and new life can come
back quickly. First smaller plants and then over time larger plants,
animals etc… until a CLIMAX community (mature thriving species) is
created.
 Ex: fire in Yellowstone Park 1988
Aquatic areas
go through
successtion too!
Keystone species  Not the most numerous or “biggest”
organism in the ecosystem, but one that is
key to other organisms success in that same
environment. If something happens to it,
other things will go too.
 Ex: Prairie dogs, otters
Major biomes:
Terrestrial
Acquatic biomes:
Freshwater:
 1. Rivers and streams – lots of oxygen, few plants.
 2. Lakes/ponds – plankton, fish
 Phyto- light so producers
 Zoo – animal so consumers
 3. Wetlands – part of the year. Cattails/red winged
blackbirds.
Marine: Oceans
 Intertidal – covered by water and exposed to air.
Barnacles, seaweed, starfish.
 Coastal – shallow water – highly productive because light
shines here. Kelp and coral reefs.
 Open ocean – 500 – 10,000 meters. Many creatures, can
be large (whales), few nutrients and producers.