Leaving Certificate Agricultural Science

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Leaving Certificate Agricultural Science
Animal Classification
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Learning Outcomes

• Classification system- Taxonomy
• Invertebrates Vs Vertebrates
• Phyla
• Agricultural Importance of Invertebrates and
  Vertebrates
• Characteristics of Invertebrates.
• Incomplete and Complete Metamorphosis

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Introduction

• Since there is such a variety of living things,
  it is important that we are able to put them into
  groups.
• This is known as classification and the area of
  study is called taxonomy.
• The method used today classifies organisms into
  one of five different Kingdoms, based upon
  similarities in their structures.
• The five Kingdoms are Monera, Fungi, Protista,
  Plantae and Animalia.
• Kingdoms are further classified in Phyla (Phylum
  in singular), then into Classes, then Orders
  (sometimes), then Families (sometimes) and then
  the organism is given a Genus and Species Name.

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Animal Classification

• Animals are classified into two main groups,
  Invertebrates and Vertebrates.
• Invertebrates (slugs and insects) do not have a
  backbone, while vertebrates (Humans, birds and
  mammals) do.
• The animal kingdom is further divided into 20
  phyla, of which the following are of agricultural
  importance

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Kingdom Protista

• This Kingdom includes many unicellular
  free-living animals called protozoans (one cell).
• It was previously considered a phylum to the
  animal kingdom, but has recently been placed in a
  Kingdom of their own along with Algae.
• Most of them live in water, either seawater,
  fresh water or soil borne water.
• They are nearly all microscopic.
• The various species of Protozoans move in a
  number of ways
• Pseudopodia (False feet)
• Cilia (Small moving hairs)
• Tails

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Kingdom Protista - 2

• Reproduction of protozoans occurs by means of
  binary fission or mitosis.
• Amoeba is one of the most common protozoans and
  moves by means of pseudopodia.
• One of the most agriculturally important species
  of Protozoans is Babesia.
• This protozoan causes Red-water Fever, a disease
  that affects 100,000 cattle a year.

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Phylum Platyhelminthes

• The phylum Platyhelminthes are dorso-ventrally
  flattened and have a definite anterior and
  posterior end giving them bilateral symmetry. 
• Some flatworms are parasites, while others are
  free-living carnivores or scavengers. 
• Examples of parasitic flatworms are flukes and
  tapeworms.
• Flatworms also have only a mouth for both food
  and wastes. 
• Their nervous system is composed of a nerve net
  and sometimes light-sensitive eyespots at the
  anterior end. 
• The phylum is classified into three main groups
  or classes
• Class Turbellaria (Free living)
• Class Trematoda (Parasitic Flukes)
• Class Cestoda (Parasitic Tapeworms)
• All platyhelminths are hermaphrodites (are both
  male and female) and can, if required, can
  fertilise themselves.

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Phylum Platyhelminthes - 2

• The most important agricultural species of
  platyhelminths is the Liver Fluke or Fasciola
  hepatica.
• The life cycle of the liver fluke is very
  important in finding ways of controlling the
  disease.
• The Life cycle is complicated and the fluke must
  lay huge amounts of eggs to survive.
• The lifecycle takes place in the cow, on grass
  and in a secondary host (the mud snail).

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Platyhelminthes - 3

• The Liver fluke lives in the ducts of the liver.
• The fluke lays eggs in the bile ducts (20,000 or
  so a day)
• The eggs pass in the faeces and hatch two weeks
  later in water and form a ciliated Miracidium.
• The Miracidium enters the foot of the mud snail
  and changes into a Sporocyst.
• Still inside the snail, the Sporocyst changes
  into a Redia.
• The Redia then produce very small tadpole shaped
  Cercaria.

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Platyhelminthes - 4

• For every Miracidium that enters the snail,
  10,000 Cercaria can be produced.
• The Cercaria then leaves the snail and goes onto
  grass.
• There it becomes encysted (forms a shell) and
  waits to be eaten by a sheep or cow.
• If eaten, the stomach acids dissolve the cyst and
  the liver fluke moves to the liver and restarts
  the cycle.

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Life Cycle of Liver Fluke
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Control of Liverfluke

• Understanding the lifecycle of the liver fluke
  allows us control the spread in the following
  ways
• Dosing any animals to kill the adult fluke
• Spraying molluscicides to kill the snail.
• Draining land (the snail only lives in water)
• Fencing flooded areas
• Dont graze wet lands after August

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Phylum Nematoda

• The phylum Nematoda are the roundworms. 
• Roundworms are cylindrical in shape, tapered at
  both ends, and vary in length from being
  microscopic to  20 inches long. 
• Unlike flatworms, roundworms have a complete
  gut. 
• This means that they have a one-way digestive
  tract with a gut that begins with a  mouth and
  ends with an anus.
• Therefore, they are usually able to digest food. 
  
• However, roundworms have no blood or heart.

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Nematoda - 2

• Most roundworms are parasites and are found in
  all habitats.
• They have separate sexes generally and reproduce
  sexually. 
• The roundworm Trichinella, causes the disease
  called trichinosis. 
• People get trichinosis from eating infected,
  undercooked pork. 
• All these worms reproduce by laying thousands of
  eggs, which become encysted in the grass and wait
  to be ingested.
• The most important agricultural species are
• Lungworms (Causes Hoose)
• Hairworms (Worms in school children)
• Potato eelworm
• Stomach worms

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Nematoda - 3

• Trichinella gets into muscles and leaves calcium
  deposits which effect muscle contraction. 
• Trichinosis can affect the heart. 
• Another roundworm, Ascaris, parasitizes human
  lungs.
• The Filaria worm attacks the lymphatic system
  causing great swelling.
• This condition is called elephantiasis.
• Hookworms and pinworms are also roundworms which
  parasitize humans.

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Phylum Annelida

• The phylum Annelida are the segmented worms and
  are abundant in all habitats.
• Segmentation gives worms more flexibility in
  movement.
• If one segment is damaged, it isn't usually fatal
  to the animal because their organs are duplicated
  in other segments. 
• Annelids have a A tube within-a-tube body plan
  known as a coelom which is fully lined and
  contains the body organs. 
• The coelom runs from the mouth to the anus.
• Annelids have bilateral symmetry and a
  well-developed brain.
• Earthworms belong to this phylum. 

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Annelida The Earthworm

• Each segment of the earthworm has setae or
  external bristles made of chitin.  These bristles
  allow the earthworm to move and to burrow into
  soil.  
• Earthworms have a head and a central nervous
  system. 
• Earthworms respire through their moist skin as
  they dig through the soil and help loosen it.
• They have a closed circulatory system in which
  blood is pumped by five pairs of hearts. 
• Most earthworms feed on decomposing vegetation
  causing it to decompose faster.
• Earthworms bring the nutrients from the subsoil
  to the top soil, thereby helping plants to grow. 
  
• Undigested materials or castings are deposited
  outside burrows.

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Earthworms and Soil

1. They eat their way through the soil and mix the
   ingested material with mucus in their guts. This
   helps to improve soil crumb structure.
2. Depositing soil in different places and mixing
   horizons.
3. Improve drainage of heavy clay soils
4. Introduces more air into the soil.
5. When they die the further increase the amount of
   organic matter.

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Phylum Mollusca

• The molluscs include slugs, snails, squid,
  mussels, clams and octopus.
• These animals generally have a foot, which
  excretes a slimy mucus.
• They also have a rasping tongue.
• The most important mollusc is the mud snail
  (Lymnaea truncatula)

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Arthropoda

• The members of the phylum Arthropoda all have
  jointed appendages. In fact, the word "arthropod"
  means jointed leg. 
• There are more species of arthropods than any
  other phylum.
• Arthropods have these characteristics
• Hard exoskeleton which is usually composed of
  substance called chitin
• Go through periodic ecdysis (moulting) as they
  shed or moult their exoskeleton
• They have specialized body segments (head, 
  thorax, cephalothorax, abdomen)
• Jointed appendages such as legs, antenna, and
  mouthparts.  
• Open circulatory system  (blood is pumped out of
  blood vessels into the body)
• The most important groups of arthropods are as
  insects, spiders and crustaceans.

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Arthropoda Class Insecta

• They have three main body parts Head, thorax and
  abdomen
• They include aphids, lice, fleas, crane-flies and
  butterflies.
• The life cycle of all insects follows this path
• Egg Larvae Pupa Adult
• The larva is another name for a maggot and the
  pupa is a cocoon.

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Aphid
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Lice
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Fleas
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Crane Fly
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Crane Fly Larvae Leather Jackets
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Class Arachnida

• The spider has two main body segments, the
  cephalothorax and the abdomen.
• Some of the diseases spiders cause on the farm
  are mange (scabies) and mite attack.
• Ticks are blood sucking spiders that can attack
  sheep and spread disease (red water fever)
• Mange is again caused by borrowing into the skins
  and laying eggs.
• The animal suffers from a severe allergic
  reaction and secondary bacterial infection can
  occur.

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Mite
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Phylum Arthropoda - Parasites

• A lot of the members of phylum Arthropoda are
  Parasites.
• Parasites are animals that live at the expense of
  other animals.
• There are two main classes of parasites
• Endoparasite inside animals
• Ectoparasites outside animals.

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Phylum Chordata

• All animals in the phylum Chordata have backbones
  and are vertebrates.
• Examples include fish, birds, amphibians,
  reptiles and mammals.
• The two main agricultural classes are Class Aves
  (Birds) and Class Mammalia (Mammals).
• Only these two classes are said to be
  homoeothermic warm blooded and can regulate
  their body temperature.

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Class Aves

• All members of this class have feathers, no teeth
  but a beak, lightened bones and no bladder

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Class Mammalia

• All mammals have the following traits
• Hair
• A Placenta
• Mammary glands to produce milk
• Again they are further classified into sub
  classes.
• Some of the common sub classes are
• Carnivores (Dogs and cats)
• Ungulates (Hooved animals)
• Odd toed - horse
• Even toed sheep, cattle
• Marsupials kangaroos
• Primates monkeys and humans

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