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