Transcript 83. - Berwick Area School District / Overview

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Natural Selection causes some organisms to
be better adapted (suited) to the
environment, and so these creatures are more
likely to survive and reproduce.
Ex: rabbits living in a snowy environment;
white rabbits are more likely to escape attack.
When all the brown ones are eaten, the rabbit
population changes to ONLY white rabbits–
we call this change in a population over
time: evolution
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Nature selects certain individuals to survive.
White fur is a more useful adaptation
(physical characteristic that improves survival)
for hiding in snowy conditions.
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Niche (rhymes with “witch”) is an organism’s
role or job in the ecosystem.
There are 5 major niches:
1) producer (makes food by photosynthesis)
2) herbivore (eats plants)
3) carnivore (eats other animals)
4) omnivore (eats both plants and animals)
5) decomposer (breaks down dead organisms)
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http://www.sheppardsoftware.com/content/a
nimals/kidscorner/games/animaldietgame.ht
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Predators are carnivores designed to be
excellent hunters/killers.
Predator adaptations for hunting include:
speed, sharp teeth, long claws, etc.
Prey are the animals that are hunted & eaten.
Prey adaptations for survival could include:
camouflage (blending in), sharp spines, etc.
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Symbiosis is a close relationship between two
species in which at least one of them benefits
Three types of symbiotic relationships exist:
1) Mutualism – both species benefit from
close contact
2) Commensalism – one species benefits
while the other is neither helped or hurt
3) Parasitism – one organism lives on or
inside another organism that is harmed by
this relationship
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The Cleaner Shrimp and Cleaner Wrasse both
work to remove parasites and dead skin from
larger fish
http://www.youtube.com/watch?v=OMFiI2at1
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A freshwater crab and some algae
http://www.youtube.com/watch?v=8K3rgj6f_I
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A parasitic wasp has inserted its eggs inside
the body of a caterpillar
http://www.youtube.com/watch?v=vMGLWyNcAs
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A leech draining blood from a man’s arm
http://www.youtube.com/watch?v=cQGXmU-cuo