What is the world’s most abundant
animal?
The worlds most abundant
animal!
• Copepods!
Wow.• How many copepods are there on earth?
• Estimate:
• 71% of the planet is ocean, average depth of 3.7km.
• This makes 1.347 x109 cubic kilometers of water on earth
• Copepods live at all depths. Assume 1 copepod per liter.
• 1 cubic kilometer = 1 x1012 liters of water
• That means there are approximately 1.347 x1021 liters of • That means there are approximately 1.347 x1021 liters of
water on the planet.
• That give us an estimated total of …..
• 1,347,000,000,000,000,000,000 copepods living on earth
• 7,100,000,000 people on the planet right now
• Source: Boxshall GA. 1998
Phylum Arthropoda
There are approximately
1,500,000 species of animals
on the planet.
Of all animal species, it is
estimated that there are estimated that there are
1,250,000 species of arthropods.
They are the most dominant animal
group on the planet.
Animal Species on Earth
Vertebrates
Nonarthropod
Invertebrates
Arthropods
What is an arthropod?
• Crustaceans
– Crabs, Lobsters, Shrimp, Crayfish, Krill
• Spiders and their friendsSpiders and their friends
– Spiders, Scorpions, Horseshoe crabs, Ticks, Mites
• Insects and their friends
– Insects, Centipedes, Millipedes
Time for examination
• Name the groups
• Identify common characteristics
• Review hypothesis
What has made arthropods so
successful?
What is an arthropod?
• Arthro
• Poda
Characteristics of phylum
Arthropoda
1. Bilateral symmetry
2. Segmented body
3. Hard exoskeleton
4. Jointed appendages4. Jointed appendages
5. Growth followed by molting
Characteristics of phylum
Arthropoda
6. Reduced coelom
7. Open circulatory system
8. Complex muscular system
9. Metamorphosis is common9. Metamorphosis is common
Why are arthropods so successful?
• They have adapted to
their individual
environments
– Evolution!– Evolution!
• Fewer body segments
• Specialized appendages
Shape of life
• http://shapeoflife.org/video/phyla/marine-
arthropods-successful-design
Body Structure
Segmentation
• Body is arranged into 2, 3 or many segments
– Cephalothorax-abdomen
– Head - Thorax – Abdomen
– Trunk segments
• Each segment is modified for specific functions
Segmentation
• What is each segment
modified for?
Segmentation
• Cephalothorax-abdomen
Exoskeleton• Hard outer body covering - chitin
– Protects body
– Site of muscle attachment
– Prevents water loss
Jointed Appendages• Found in pairs
• Antennae, legs, mouthparts
– Adapted for: feeding, mating,
sensing, walking, swimming
Molting
• Hard exoskeleton cannot grow– Must be shed and new one formed
– Video
Feeding and Digestion
• All strategies
– Herbivores, Carnivores,
Omnivores, Filter feeders,
Parasites, Detritivores
– Specialized mouthparts– Specialized mouthparts
• Complete digestive tract
Respiration• Most aquatic arthropods have gills
• Most land arthropods have a tracheal system
– Tubes bring air into the body and close to tissues
– Spiders have book lungs
Circulation
• Heart with open system
Excretion
• Land arthropds have
Malpighian tubules
which concentrate
waste from the waste from the
blood
– Excretory waste
added to digestive
waste
Response and Senses• Brain and ventral nerve cord
– Powers muscular system
– Individual ganglia control
appendages
• Compound eyes • Compound eyes
Movement
• Complex muscular
system
– Muscles pull on
exoskeletonexoskeleton
– Flying, walking
swimming
• Body joints can be
straightened or bent
by muscles
Reproduction
• Land arthropods have internal fertilization
– Specialized organs or sperm packets
• Aquatic arthropods have internal or external
fertilization
Things to research
• Feeding and Digestion
• RespirationRespiration
• Circulation
• Excretion
• Response to stimulus
• Movement
Other things to include
• Special adaptations that make them
successful?
• Pictures
Animals to pick from
• Subphylum Chelicerata
• Class Merostomata – horseshoe crabsClass Merostomata – horseshoe crabs
• Class Arachnidia
– Order Scorpionida - scorpions
– Order Araneae- spiders
– Order Opiliones - spiders
– Order Acarina – mites and ticks
• Class Pycnogonida- sea spiders
Animals to pick from
• Subphylum Crustacea
• Class MalacostracaClass Malacostraca
– Order Decapoda- crabs, lobsters, shrimp
– Order Isopoda- pill bugs
– Order Amphipoda- amphipods
• Class Branchiopoda – brine shrimp,
fairy shrimp, daphnia
• Class Maxillopoda- barnacles and
copepods
Animals to pick from
• Subphylum Myriapoda
• Class Diplopoda-millipedesClass Diplopoda-millipedes
• Class Chilopoda- centipedes
• Subphylum Hexapoda
• Class Insecta
– Ephermeroptera-mayflies
– Odonata- dragonflies
– Plecoptera- stoneflies
– Mantodea- mantids– Mantodea- mantids
– Blatteria- roaches
– Isoptera- termites
– Dermaptera- earwigs
– Orthoptera- grasshoppers
– Phasmida- sticks
– Hemiptera-true bugs
– Coleoptera- beetles