Transcript 34-3: Comparison of Invertebrates + Vertebrates

32-2: Comparison of
Invertebrates + Vertebrates
Invertebrate characteristics
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Symmetry
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Radial or bilateral
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Aquatic – radial; Terrestrial – bilateral
Most animals display bilateral for motility + sensory
functioning (i.e. a BRAIN)
Segmentation
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A body composed of a series of repeating similar
units
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Simple (earthworm) to complex (Arthropods)
Let’s look at these two…
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Symmetry
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Segmentation
Invertebrate characteristics
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Support of the body
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Simple skeletons
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Pressure fluid-filled cavity
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Ex. Sponges
Ex. Roundworms
Exoskeleton – rigid outer covering
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Ex. Lobster + clam
Invertebrate characteristics
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Respiratory + Circulatory Systems
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Gas exchange – CO2 + O2 in blood
Circulatory system – moves blood or fluid
(hemolymph) through body to transport nutrients or
O2 to cells
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Types of circulatory systems:
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Diffusion – Ex. Sponges + Cnidarians
Open – bloodlike fluid pumped from vessels into body
cavity, then pumped back; Ex. Grasshopper
Closed – blood circulates through body in tubular vessels;
Ex. Earthworm
Let’s look at these two…
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Respiratory
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Circulatory
Invertebrate characteristics
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Digestive + Excretory systems
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Digestion
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Sponges –occurs in individual cells
Cnidarians – central chamber
Most others have a digestive tract (gut) to breakdown
food to absorb nutrients
Excretion – removal of wastes
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Aquatic – wastes are excreted as dissolved ammonia
(NH3)
Terrestrial – wastes are filtered before removed;
water gets reabsorbed
Let’s look at these two…
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Digestive
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Excretory
Invertebrate characteristics
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Nervous System
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Sponges
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No neurons – nerve
cells
Individual cells can
react to external
stimuli
Most other organisms
may have some sort of
cephalization
Invertebrate characteristics
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Reproduction + Development
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Capable of both sexual + asexual
Some are hermaphrodites
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Organism that produces both male + female gametes
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Indirect development
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Ex. Earthworm
Larval stage - change of appearances
Direct development
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No larval stage
Animal is born or hatched – no change in appearance
Let’s look at these two…
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Indirect
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Direct
Vertebrate characteristics
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All vertebrate classes, except fish, spend part
or all of their life on land
Categories for terrestrial adaptations:
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Support of body
Conservation of water
Vertebrate Characteristics – highlights
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Have the following:
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Body support – endoskeletons (backbone/vertebrae)
Body covering – integument
Gas exchange – lungs/gills
Circulatory - multichambered heart
Digestive – gut (mouth to anus) = 23 ft long in humans
Excretory – kidneys
Nervous – highly organized brains
Reproduction – fertilization of egg (zygote)
Development – direct development, except amphibians