Species Interactions & Community Ecology Environmental biology

Case Study  Mussels & the Great Lakes  Border of US and Canada  5 giant lakes & a number of small ones  These were formed by the last Ice Age  More polluted in the past  Took ‘Big Government’ intervention to clean up - Clean Water act, 1970  Arrived by ship from Europe 

Case Study cont…  Within 2 years the mussels had established themselves in all the Great Lakes  Then spread even further to the great Mississippi River Watershed - 40% of US land mass.  Their main limiters were absent here  Predators  Competitors  Parasites

Case Study cont…….  IMPACT  = Economic mostly  = industrial interference  = infrastructure damage  = Ecological  = Overeat the native phytoplankton  = Kill local molluscs  = Alter local ecology towards bottom dwellers  Permit more light penetration  Deposit organic matter on bottom

Case Study cont…….  However, recently they are being replaced by another species  Quagga mussel is moving in  It is reducing the zebra mussels  What impact this new one shall have? We will have to wait and see….

INVASION!!!!!  Look up and see. They are coming…  ___________ ___________

What is ecology?  The study of how organisms interact with each other and their physical environment.

Species Interactions  Species interact with each other  Many ways have been studied and documented  Some are beneficial to both species  Other to one or the other  And some to neither….

Species interaction types

 Intraspecific - within a species  Example = _______________????  Interspecific - between species  Example = _______________????  Solution is resource partitioning = basically sharing by adapting  There is a total negative effect on both! Competition

Predation  One species kills the other to live  Predator is the killer  Prey is the victim  Example = _______________????  Drives evolution - Natural selection  These interaction are direct and do generally cycle…

Figure 5.2

Parasites  No immediate death involved  Example = _______________????  Parasite depends on the host for food and shelter  The host is harmed to some degree!  The parasite benefits entirely  Co-evolution also works here

Herbivory  Animals feed on plants  Insects on plants  Example = _______________????  Plant does not die (at least not initially)  Plants defend themselves too  Example = _______________????  Evolutionary Arms Race!

Mutualists  Both are good for each other  Provide other with something it needs  Example = _______________????  Symbiotic  Example = _______________????  Pollination  Example = _______________????

Ecological Communities  Each has its;  Producers - make food  Consumers -  Primary - grasshoppers  Secondary - frogs  Tertiary - birds  Decomposers - Nonliving organic consumers  recyclers

Food chains & Energy  As one feeds on another, in a community, there is a relationship built - this is known as the food web.  As one moves further away from produces then amount of energy available is reduced (by 90% per level)  Energy Pyramid

Keystone Species  If you were to eliminate a single species from a community and see the effects of that action, one would notice:  Most have little impact  One will devastate the ecosystem  This one species is the keystone species  Example = _______________????

Ecological Succession  A new volcanic island will be populated by life in a predictable way;  Primary succession - No life at beginning  Primary species = first  Example = _______________????  Secondary succession - Some form of life or organic matter remains - and it starts with that.  WATCH ME! WATCH ME!

Biomes  What are they?  Just regions of the planet with certain similar communities of life.  The Earth has 12 such regions  TGEplbU TGEplbU

Biomes…  In general, there is no sharp demarcation between biomes.  Life on Earth is a continuum based on moisture and heat…

Other Biomes…  Also, there are aquatic biomes too…  These are considered later in the course