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The study of the interactions of living organisms with one another and their environment.
2 distinct groups:
Bi otic = living
Ex: animals, plants, fungi etc.
Abiotic = non-living
Ex: rocks, water, soil, light etc.

Organization in the environment: in order from largest scope to smallest...
Biosphere - contains all life on the planet
Biome - group of ecosystems with the same climate and similar communities
NOTE: there are many Biomes which we will explore! More to come!
Ecosystem - collection of all organisms within an area along with their physical environment
~ contains both biotic and abiotic factors
Communities - more than one population in a defined area
Population group of individuals in the same species that live together in a defined area
Individual - one of one type of species

Living things need ENERGY !
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Organisms can be divided into 3 groups depending on how they obtain energy:
1.) Producers:
~ use sunlight to directly make their own food
~ Photosynthesis
~ Ex: Plants, algae etc.
2.) Consumers:
~ need to eat other organisms
~ 3 types:
* Herbivores - eat plants (producers)
* Carnivores - eat animals
* Omnivores - eat both plants and animals
Fly agaric fungus
3.) Decomposers:
~ get energy from breaking down dead organisms
~ Ex: bacteria and fungi
~ Are "nature's recyclers" slime mold
Bracket fungus

Food chain: energy flows through an ecosystem in one direction...
sun a producers a consumers
Here are a few examples:

Food web: a network of complex interactions - they link all the food chains together in an ecosystem!
Two actual food webs on earth: Land web and Aquatic web
Just like in the food chain, the arrows show that an organism is food for another.
Which is food for the Birds?
Which is food for the Elephant Seal?
What is the main producer?
What is the top predator?
**Each time something consumes another org., the energy that is not immediately used from that food gets stored in the consumer's tissues. This energy is what then can be passed on once that organism is eaten by something else.

So How Does the Energy Transfer Along the Web?
We can see by using Energy Pyramids !
Because only 10% of the energy of the previous level transfers to the next level, less energy is available at the higher trophic levels.
**This is also why there are more producers than consumers!
Food webs and chains are kept in balance by nature.
For example...
Gray Wolves control the populations of many other animals.
When the wolves were hunted to the brink of extinction, it threw off the balance of the rest of the food web!
Effects: ~ prey populations went up
~ producer populations went down
~ primary consumers began to overbreed and then were starving!
Once the wolves were re-introduced to their home, they started to breed...
Effects: ~ prey populations went down into normal
~ the producer populations came up into normal ranges
~ the web began to balance ranges

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There are several limiting factors that keep populations in check...
1.) Competition for food - more org. = less resources
2.) Predation - predator-prey relationships keep each other in balance
3.) Parasitism and Disease - keeps populations down by killing host
4.) Drought / Climate extremes - extreme heat or cold, lack of or too much water...all can kill
5.) Human disturbances - changing the ecosystem
~ deforestation, waste dumping, killing off predators
Amazon deforestation
Landfill

Populations can grow exponentially if not kept in check.
Just FYI:
~ one bacteria will become
2, then 4 then 8,then 64, then 512,then at the end of one day, there will be
*
4.72 x10 21
Called Exponential Growth!
However, this only happens when populations have every offspring survive to reproduce.
As resources become less available, offspring don't live as well. This stops population growth.
~ This happens when the population has reached carrying capacity
. max # org. an ecosystem can support

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4 Main Ways:
1.)
Competition
- species have similar needs and compete for survival within a population or between similar populations
~ Ex: a population of Elk may compete for the same food plants
Species of trees may compete for sunlight and space in a forest.

2.)
Predation
- one org. eats another
*back and forth adjustment between the 2 results in coevolution ex: the faster the prey gets, the faster the predator gets and vice versa
With this interaction may come several adaptations...
1.)
Camouflage
~
Blending in with the background due to coloration, shape, or action
Let's see it in action...
http://www.bing.com/images/search?q=camo uflage&view=detail&id=0B842C5DFA4C0C4
0F17F313E98D2BC3EF9FD5E69&first=31&
FORM=IDFRIR
View the "Hidden in Plain Sight" clip!
2.) Defensive Chemicals
~ some can spray with an irritating or offensive chemical
* skunk
~others exude the chemical and cause terrible even fatal reactions!
*poison dart frogs
Poinson Ivy uses urushiol
3.) W a r n i n g Coloration
~ Bright colors tell would be predators to stay away!
~ Indicates the animal is dangerous in some way...
*poisonous, venomous, or toxic
*have harmful defense quills, stingers etc.
Yellow jacket - painful sting!
Pitohui - a poisonous bird!
Coral snake - venomous!

Let's learn a bit about this...
http://www.youtube.com/watch?v=zSmL2F1t81Q
3 types: a.) Mutualism - both species benefit b.) Commensalism - one benefits, the other is neither helped or harmed c.) Parasitism - one org. lives on another and harmed ex: tapeworms in mammals the host is
Tick
Tapeworm
Leeches anyone? Let's check out these parasites!
http://www.youtube.com/watch?v=cKUAroimQrk
Wasp larvae on a tomato hornworm

4.) Coevolution
When long term change takes place in two species due to their close interactions with each other
Ex: Ants and the Acacia tree Let's see this in action!
http://video.nationalgeographic.com/vid eo/kids/animals-pets-kids/bugskids/ant-acacia-kids/
The Acacia tree provides nectar or food for the ants while the ants attack anything that tries to eat the leaves.
This is a type of mutualism too!
Here's another example...
Madagascar Hawkmoth and Darwin's Orchid
*This orchid is only pollinated by this species of moth.
*Over many generations, as one specie changed, so did the other.
Let me explain...as the orchid tube that contains the nectar (food for the moth) changed over time to become elongated through mutation, the moth with the longer proboscis survived to reproduce, passing down long proboscis genes. Those with proboscises that were too short, died off leaving those with the longer genes behind to reproduce. Thus, as the flower population changed, so did the moth population. They influenced one another's change over time!
This is what is meant by coevolution!
So what does each get out of this relationship?
~Moth gets a meal
~Flower gets pollinated
There are many, many examples of this...please feel free to research them for extra credit!