Arthropods, Echinoderms

1
Arthropods, Echinoderms
2
Phylum Arthropoda

• Characteristics
• Largest group of animals
• Have jointed appendages which include legs,
  antennae, claws and pincers
• Have bilateral symmetry, segmented bodies,
  exoskeletons, a body cavity, a digestive system
  with two openings and a nervous system
• Most have separate sexes and reproduce sexually

3
Arthropods

• Body Segments
• Bodies of these animals are divided into segments
  similar to segmented worms
• Some have many segments, others have segments
  that are fused together to form body regions
• Exoskeleton
• A hard outer covering that supports and protects
  the internal body and provides places for muscle
  to attach.
• Doesnt grow as the animals does, it is shed and
  replaced during a process called molting

4
Insects

• Have three body regions
• Head
• Has a pair of antennae, eyes and a mouth
• Thorax
• Three pairs of legs and one or two pairs of wings
  if present are attached here
• Abdomen
• Where reproductive structures are found

5
Insects

• Have an open circulatory system that carries
  digestive food to cells and removes wastes
• Insect blood doesnt carry O2 instead air enters
  and exits through openings called spiracles found
  on the abdomen and thorax
• Are the only invertebrate animals that can fly

6
Metamorphosis

• A series of changes that an insect goes through
• Two types
• Complete
• Includes stages of egg, larva, pupa, and adult
• Ex. Butterflies, bees, flies
• Incomplete
• Includes stages of egg, nymph, adult
• The nymph form molts several times before
  becoming an adult
• Ex. Grasshoppers, crickets

7
Insects Food

• Feed on a number of things have different mouth
  parts to obtain food
• Grasshoppers and ants have large mandibles for
  chewing
• Butterflies and honey bees have siphons for
  lapping up nectar
• Aphids and mosquitoes have mouth parts that are
  adapted for piercing into plants or other
  organisms

8
Insects success

• Insects are extremely successful based these
  reasons
• Tough flexible, waterproof exoskeleton
• Ability to fly
• Rapid reproduction cycles
• Small sizes
• Insects have other adaptations that allow them to
  be successful

9
ORDER LEPIDOPTERA
What is the difference between a moth (1st
picture) and a butterfly (2nd) ?
Moth antennae end in clubs, theyre bodies are
often furrier and when at rest, their wings are
flat (butterflies rest with the wings pointing up
10
Arachnids

• Have two body regions
• Cephalothorax and an abdomen
• Four pairs of legs and no antennae
• Many are adapted to kill prey with poison glands,
  stingers, or fangs
• Some are parasites

11
Arachnids

• Scorpions
• Have sharp, poison filled stinger at the end of
  abdomen.
• Have a well-developed appendages which they can
  grab their prey.
• Spiders
• Cant chew their food, release enzymes into prey
  to digest itthen suck the predigest liquid into
  its mouth.
• Have book lungs where O2 and CO2 are exchanged.

12
(No Transcript)
13
(No Transcript)
14
Brown recluse bites cause necrosis (death of
tissue).
15
Arachnids

• Mites Ticks
• Most are parasites
• Ticks have specialized mouthparts to remove blood
  from the host.
• Ticks often carry disease such as Lyme disease.

16
Centipedes Millipedes

• Have long bodies and many segments, exoskeleton,
  jointed legs, antennae and simple eyes.
• Found in damp environments
• Reproduce sexually
• Make nests for eggs and stay with them until they
  hatch.
• Centipedes are predators
• Millipedes feed on decaying plant matter.

17
(No Transcript)
18
(No Transcript)
19
(No Transcript)
20
Crustaceans

• Have one or two pair of antennae and mandibles,
  which are used for crushing food.
• Most live in water, but some live in moist
  environments on landsuch as pill bug.
• Have five pair of legs, first pair of legs are
  claws for catching and holding food.

21
Crustaceans

• Swimmerets are appendages on the abdomen which
  help in movement and are used in reproduction
  also force water over the gills used in O2 and
  CO2 exchange
• If a crustacean loses an appendage it can
  regenerate it
• Include crabs, crawfish, shrimp, lobster, and
  sowbugs (rolypolys)

22
(No Transcript)
23
Value of Arthropods

• A source of food
• Agriculture would be impossible without bees and
  other insects to pollinate crops
• Useful chemicals are obtain from some arthropods
• Important part of ecological community

24
Controlling Insects

• Not all arthropods are of value some are pests
  that carry disease or can damage crops

25
Controlling Insects

• Common ways to control insects
• Insecticides, but these also kill non-harmful
  insects
• Biological controls
• Types of bacteria, fungi, and viruses can be used
  to control insects
• Natural predators being released to kill the
  harmful insect
• Some how interfere with reproduction of the
  particular insect

26
Origin of Arthropods

• Some fossils are more than 500 million years old
• Scientist hypothesized that arthropods probably
  evolved from an ancestor of segmented worms
  because they have body segments
• The hard exoskeleton and walking legs allowed
  arthropods to be among the first animals to live
  successfully on land

27
Phylum Enchinodermata

• Characteristics
• Have an endoskeleton covered by a thin, bumpy or
  spiny epidermis
• Radial symmetricalallowing them to sense food,
  predators and other things in the environment
  from all directions
• Have mouth, stomach, intestines
• Feed on a variety of plants and animals
• Have no head or brain, but have a nerve ring that
  surrounds the mouth
• Also have cells that respond to light and touch

28
Water-Vascular System

• A characteristic unique to echinoderms
• Allows them to move, exchange CO2 and O2, capture
  food, and release wastes
• It is a network of water-filled canals with
  thousands of tube feet connected to it.
• Tube feethollow, thin walled tubes that ends in
  a suction cup.
• As pressure in the tube feet changes the animal
  is able to move along by pushing out and pulling
  in its tube feet

29
Types of Echinoderms

• Sea Stars
• Echinoderms with at least 5 arms arranged around
  a central point
• Uses tube feet to open shells of prey, once open
  pushes its stomach into shell and uses an enzyme
  to digest it
• Reproduce sexually
• Can repair themselves by regeneration

30
Types of Echinoderms

• Brittle Stars
• Have fragile, slender, branched arms that break
  off easily
• This adaptation allows them to survive
• They can regenerate broken off body parts
• Use flexible arms for movement and tube feet to
  get food into their mouths

31
Types of Echinoderms

• Sea Urchins Sand Dollars
• Disk or globe-shaped animals covered in spines
• Spines help in movement and in burrowing
• Also can protect them from predators
• Sea Urchins have five tooth like structures
  around their mouth

32
Types of Echinoderms

• Sea Cucumber
• Soft bodied echinoderms
• Have a leathery covering
• Have tentacles around their mouth and rows of
  tube feet on their upper and lower surfaces
• When threatened, they may expel their internal
  organs which will then be regenerated in a few
  weeks

33
Value of Echinoderms

• Feed on dead organisms in the marine environment
• Help recycle material
• Used for food
• Possible sources of medicine
• Sea stars can help control the population of
  other organisms

34
Origin of Echinoderms

• Date back more than 400 million years ago
• Earliest echinoderms had bilateral symmetry as
  adults
• Scientists hypothesize that echinoderms more
  closely resemble animals with backbones than any
  other group of invertebrates
• Have similar embryos that develop similar to
  vertebrates
• Complex body systems