Transcript 4/20 & 4/21 - 7th Grade Agenda

4/20 & 4/21 - 7th Grade Agenda
Collect HW: Reading & Notetaking 196 –
197
Cnidarians & Worms
Classwork: Making Scientific Names
Pass back HW & Test
Video: Life (Deep Ocean)
Textbook Reading 417 – 421
HW: Reading & Notetaking 199– 200
Sea anemone and many circular
adial
animals exhibit R______
ymmetry
S_______
• What are some
characteristics of Radial
Symmetry Animals?
• Do not have distinct
front or back ends
• Lives in the ocean
• Senses their
environment in all
directions
The balanced arrangement of a
butterfly’s body is called
ymmetry
ilateral
B_______
S________
• What are some
characteristics of
Bilateral Symmetry
Animals?
• Larger & More complex
than radial symmetry
animals
• Moves more quickly
• Sense organ in the front
Is a Sponge an animal or a
plant?
• Sponge is an animal
• Although it cannot
move around from
place to place sponge
take food into their
bodies
What do sponges eat?
• Tiny
organisms
such as
bacteria and
protists
• Sponge gets
its oxygen
from water
• Network of
spikes support
the sponge
Sponge Larva
• Sponge reproduce
asexually and sexually
• Sponges do not have
separate sexes
• At any one time of the
year, some sponges are
producing eggs and
others are producing
sperms
What are Cnidarians?
Jellyfish Facts
•
•
•
•
They are not used to make Jelly
98% Water
No Heart or Blood
Most don’t have a brain (except
Box Jellyfish)
• Most only detect light. Some have
24 eyes (Box Jellyfish)
• When stung, Vinegar (not urine) is
the best treatment
• Irukandji Jellyfish (size of fingernail)
can kill you with a single sting.
More on Cnidarians
• Unlike sponges, cnidarians have
specialized tissues
• Muscle like tissues for swimming
• Anemones stretch out
How does cnidarians obtain and
digest food?
• Cnidarians captures
its prey by using its
stinging cells to inject
venom
• Then the cnidarian’s
tentacles pull the prey
animal to its mouth
• From there the food
passes into a body
cavity where it is
digested.
How are coral reefs made?
• Built by cnidarians
1. Free swimming coral
larva attaches to a solid
surface ( broken shell,
sunken ship)
2. The coral polyp
produces a hard, stony
skeleton around its soft
polyp body
3. Over thousands of
years, as live corals add
their skeletons, the reef
grows
What are the major type of worms
• Flatworms
• Roundworms
• Segmented Worms
Lifecycle of a tapeworm
An organism that lives inside or
on another organism and takes
its food from that organism is a
arasite
P_______
Do worms have brains?
• Yes
• They also have a heart, digestive tract and
reproductive organs
Is an earthworm helpful?
• Yes.
• Earthworm dropping
make the soil fertile.
Earthworm tunnels
loosen the soil and
allow air, water, and
plant roots through it
How do Earthworms Mate?
• Earthworms are hermaphroditic meaning
each worm has organs of both sexes.
• One worm has to find another worm in order to
mate
Do earthworms have eyes?
• They do not have eyes
• But they do possess light- and touchsensitive organs (receptor cells) to
distinguish differences in light intensity and
to feel vibrations in the ground.
What is the "bump" in the middle
of the earthworm?
• The bump is the clitellum.
• It contains the gland cells which secrete a slimy
material (mucus) to form the cocoon which will
hold the worm embryos.
Earthworm Cocoons
Can earthworms regenerate
themselves?
• Yes, but only the front or head end of the
earthworm will survive and the
amputated tail portion will die.
Virtual Dissection of Earthworm
What is the difference between
front end and back end?
Front End
(Anterior)
Back End
(Posterior)
What is the difference between
top side and bottom side?
Top side (Dorsal)
Bottom side (Ventral)
Dissecting the earthworm
Internal View
Aortic Arches (Primitive Heart)
Cross section view
Does earthworm have bilateral or
radial symmetry?
• Bilateral Symmetry