Transcript Invertebrates

Invertebrates
By: Ryan , Rachael and Darrin
Sample Organisms
Some sample organisms are …
 Jellyfish
 Grasshoppers
 Sea anemone
 Earth worm
 Sea sponge
 Spiders
 Flatworm
 Hydra
Habitat of Invertebrates
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Since all invertebrates rely on aerobic
respiration, they cannot survive in places without
oxygen.
They can live anywhere oxygen is available.
It is very hard for most invertebrates to survive in
cold weather.
Characteristics of Invertebrates
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Invertebrates don't have an internal skeleton or back
bone.
Many invertebrates have a fluid-filled, hydrostatic
skeleton. Others have a hard outer shell, like insects and
crustaceans.
Heterotrophic
No cell walls
Eukaryotic
How are invertebrates further classified?
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The animal kingdom is split up into vertebrates and
invertebrates
Invertebrates are split up into 34 different phylum including
Porifera (sponges)
Cnidarian (jellyfish)
Platyhelminthes (flatworms)
Nematoda (roundworms)
Echinoderm (starfish)
Molluska ( clams)
Annelida (segmented worm)
Arthropoda ( spiders)
Labelled Diagram of the Jellyfish
Jellyfish Nervous System
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The jellyfish has a nervous system
characterized by a series of interconnected
nerve cells (a nerve net).
The nerve net conducts impulses around
the entire body of the jellyfish.
The strength of a response is equal to the
stimulus strength. In other words, the
stronger the stimulus, the larger the
response.
The jellyfish lack a true organ system they
have no real nervous systems or brain, no
heart, and, with the exception of the box
jelly, no eyes. They don’t even have bones
or blood or dense muscles.
Corporal Structure
Symmetry
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There are many different types of inverbretes and among
them the three types of symmetry (bilateral, radial and
asymmetrical) can all be found
For example sponges are asymmetrical, Starfish and
jellyfish have radial symmetry and grasshoppers and
spiders have bilateral symmetry.
Corporal Structure
All invertebrates are classified as being
eukaryotes and are all multicellular
jellyfish.
 Almost all invertebrates have tissues
except for a select few such as sponges
 All invertebrates lack a cell wall
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Corporal Structure
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Most invertebrates have organs and the higher
invertebrates also have systems
For example grasshoppers have organs such as eyes
the heart and the reproductive organs.
They have systems such as nervous, digestive and
circulation
Reproduction and Lifecycle
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Reproduction in invertebrates can be
sexual, asexual or hermaphroditic.
For example spiders reproduce sexually. It
is every males spiders goal to get as many
females as possible pregnant.
First the male spider has to locate a
female.
Next the spider has to beat off any other
contenders to the female spider.
Next comes courtship, the male spider has
to signal he’ s the right species and not
food.
They usually express court ship through
web building. If the female accepts they
reproduce if she doesn't its all over
Reproduction and lifecycle
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Once a spider's eggs are fertilized, they have to stay
safe from predators until the spiderlings can hatch out
Some spider species will encase their eggs in a silken
pouch and abandon them, and others will stay with them
until the babies hatch.
Reproduction and lifecycle
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The spiderlings continue molting, growing larger until
they reach sexual maturity.
Then the entire cycle begins again -- males seek out
females, and females lay eggs.
Most spiders have a fairly short lifespan, ranging from a
few months to a couple of years. But some spiders, such
as various female tarantulas, can live as long as 20
years.
Respiration
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All invertebrates need oxygen to survive, meaning they do
anaerobic respiration.
For Example grasshoppers have small openings called
spiracles, on the side there abdomens . These lead to a
system of branched air tubes and tracheae, spreading
throughout the body to all the cells.
Air is pumped in and out of the tracheae by the muscular
contractions and expansions of the abdomen.
In this way O2 is brought in and CO2 is expelled
Digestion
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The many species of invertebrates use either a tubular, channelnetwork or saccular digestive system to digest food.
A channel-network is several water channels lined with whip like
structures called flagella that create a steady flow of water
currents which bring nutrients in the water to the animal. For
example sponges.
Digestion
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A tubular digestive system is with a complete tubular tract with an
opening at each end ; one end is the mouth and the other is the
anus. For example grasshoppers
A saccular digestive system has a sac-like body composed of an
outer and inner layer of cells and a central cavity. The outer layer
is for sensory and protective covering, the inner layer of cells
absorbs nutrients and the central cavity, possesses an opening
that functions as both a mouth and an anus.
Circulation
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Many invertebrates do not have a circulatory system at all.
Their cells are close enough to their environment for oxygen,
other gases, nutrients, and waste products to simply diffuse
out of and into their cells.For example
flatwormsexchange gases exclusively by diffusion through
their body surface.
In some higher invertebrates, there are two primary types of
circulatory systems -- open and closed.
Circulation
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Arthropods and mollusks for example have an open circulatory
system. In this type of system, there is neither a true heart or
capillaries as are found in humans. Instead of a heart there are
blood vessels that act as pumps to force the blood along.
The closed circulatory system of a few mollusks and
other invertebrates( for example earthworms) is a much more
efficient system. Here blood is pumped through a closed
system of arteries, veins, and capillaries, much like us humans
Interesting Facts
Invertebrates were the first animals to
evolve.
 Invertebrates account for 97 percent of all
known species.
 Invertebrates will eat almost anything that
was or is alive.
 Many of the world's parasites are
invertebrates.
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