species interactions & community ecology environmental biology
TRANSCRIPT
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
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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!
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Biomes
What are they? Just regions of the planet with certain
similar communities of life. The Earth has 12 such regions
http://www.youtube.com/watch?v=ag5ATGEplbU
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Biomes…
In general, there is no sharp demarcation between biomes.
Life on Earth is a continuum based on moisture and heat…
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Other Biomes…
Also, there are aquatic biomes too… These are considered later in the
course