Ecosystems and CommunitiesCh. 4

What is Climate?• Temperature, weather (rain, snow,

windy, etc…), amount of sunlight, etc…

• Climate the average temperature/precipitation over long periods of time

• What abiotic factors effect climate?1) Greenhouse gasses CO2, CH4,

and H2O help trap heat from the sun inside the Earth’s atmosphere

2) Latitude Earth spins at 23o angle, so northern and southern areas get less sunlight while near the equator the amount of sunlight is the same all year long

What is Climate?3) Wind and Water Currents • hotter air at the equator and

cooler air everywhere else creates wind currents that move heat around the Earth

• Same effect in water; warm water rises and cold air sinks

• Areas along these current paths gain warmer temperatures (more energy)

Niches and Community Interactions• What is a habitat?– Place an organism spends most

their life– Organisms have a Range of

Tolerance flexible conditions that it CAN survive

– All habitats must fit somewhere in an organism’s range

• What is a niche?– Specific way an organism

interacts with the environment (gets recourses, reproduces, etc…)

– What is the special rule about niches?

Competitive Exclusion Principle• No two species can have the

same niche; competition will eliminate the weaker species– Intraspecific competition

between same species• IntRA = same

– Interspecific competition between different species• IntER = different

• How do organisms limit the effects of competition?– Organisms get resources in

many ways

Resources in Cycles• Predator-Prey relationship

one animal (predator) eats another animal (prey); number of predators changes with the number of prey

• Herbivore-Prey Relationships one animal (herbivore) eats producers; plants density changes with herbivore density

• In both systems there is always a Keystone Species – Species, if removed, that would

have the greatest effect on the ecosystem

Interactions Produce Symbioses• Symbiosis close interaction

between two or more species• 3 types:1) Mutualism both animal

benefit from relationship; ex. Clown fish and Sea anemone

2) Parasitism one benefits and one is weakened (not killed); ex. Tape worm

3) Commensalism one benefits and one is not affected; ex. Barnacles on Whales

Major Shifts in an Ecosystem• Ecological Successions:1) Primary Succession first life

(pioneer species) in an area of only freshly exposed land– Volcano forms an island

2) Secondary Succession after massive destruction, surviving life spreads quickly into new space– Growth after a forest fire

• After a succession, populations grow until a Climax Community is obtained

• Studying successions and climax rate tells scientists about the history of the ecosystem

Homework• Finish reading Ch. 4 and Start reading Ch. 5• Ch. 4 “Apply Vocab” and questions #1-18 on p 103-

104 all due Friday Morning• Presentations on 2 Biomes next MondayHow to present:1) Everyone in your group speaks2) Must have a good PPT:

– Text is easy to read– NO PARAGRAPHS!– Use Pictures to help explain yourself

3) Good Presentations:– NO READING!– Speak clearly and loudly– Talk to the students, NOT to me!

4) STAY IN YOUR TIME LIMIT: 5 minutes!– If you go over your time, I will stop your group and

you will lose points• YOU GET 1 CLASS TO DO THESE

PRESENTATIONS!!!!!!!!!!!!!!!!!!!