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Group report :) Made by yours truly.
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Nervous Response Earthworm
Donato. Esteban. Madriaga. Tolentino.
WHAT ARE EARTHWORMS?
Earthworms are segmented animals commonly found living in soil that is shaped like a tube (the gut) within a tube (the body). Its digestive system runs straight through its body and it conducts respiration through the cuticle covering of its skin. It has a simple, closed blood circulatory system.
The nervous system allows the body to respond to various changes in the environment.
Receptors are groups of specialized cells that can detect changes in the environment, which are called stimuli, and turn them into electrical impulses. Receptors are often located in the sense organs.
An effector is any part of the body that produces the response.
Reflex actions are extra-rapid responses to stimuli. It also involves the nervous system, but bypasses the brain. When a receptor is stimulated, it sends a signal to the central nervous system, where the brain co-ordinates the response.
TAXIS VS. TROPISM
Tropism involves an organism (mainly plant) growing toward or away from a stimulus.
Taxis involves an organism (protist or animal) moving toward a stimulus.
MATERIALS:
Earthworms
MATERIALS:
Dissecting pan
MATERIALS:
Wet paper
MATERIALS:
Dissecting needle
MATERIALS:
A card with a 2 millimeter hole
MATERIALS:
Flashlight
MATERIALS:
Alcohol lamp (with matchsticks)
MATERIALS:
Glass rod
MATERIALS:
Xylol (Reagent)
Methodology
Wash the dissecting pan
Cover the pan with a sheet of
wet paper
Place an active live
earthworm
Methodology: Contact
Touch the earthworm’s
anterior part with the needle
Touch the earthworm’s
posterior part with the needle
Touch the earthworm’s
middle part with the needle
Methodology: Light
Use a flashlight to shine on the earthworm’s anterior part
Use a flashlight to shine on the earthworm’s posterior part
Use a flashlight to shine on theearthworm’s middle part
Methodology: Heat
Place the heated end of the rod on the earthworm’s
anterior part
Place the heated end of the rod on the earthworm’s
posterior part
Place the heated end of the rod on the
earthworm’s middle part
Methodology: Moisture
Line a clean and dry dissecting pan with a tissue paper
Dampen one half of the tissue and let the other half
stay dry
Place the worms at random locations.
Observe its location.
Methodology: Chemical
The tip of the glass rod (with xylol) was placed near the earthworm’s
anterior part
The tip of the glass rod (with xylol) was placed near the earthworm’s
posterior part
The tip of the glass rod (with xylol) was placed near the earthworm’s
middle part
Results: Contact
Results: Contact
Results: Contact
Results: Light
Results: Light
Results: Light
Results: Heat
Results: Heat
Results: Heat
Results: Moisture
DRY WET
Results: Moisture
DRY WET
Results: Chemical
Results: Chemical
Results: Chemical
Results
STIMULUS ANTERIOR REGION
MIDDLE PART
POSTERIOR REGION
CONTACT + - +LIGHT + - +HEAT + + +
MOISTURE + + +CHEMICAL + + +
DISCUSSION
References
Answers. Answers Corporation. Accessed on 27 July 2012 <http://wiki.answers.com/Q/What_is_the_difference_between_taxis_and_tropism>.
BBC. BBC Vision. Accessed on 27 July 2012 <http://www.bbc.co.uk/schools/gcsebitesize/science/aqa_pre_2011/human/thenervoussystemrev1.shtml>.
Wikipedia. Wikimedia Foundation, Inc. Accessed on 27 July 2012 <http://en.wikipedia.org/wiki/Earthworm>.
THANK YOUFOR
LISTENING!