Animal Classification

• The Invertebrates


• Invertebrates are animals with no backbone.
  A species is a group of closely related organisms which interbreed and produce fertile offspring e.g. horses, dogs, cats, humans etc.
  There are between one and two million species.
  Based on a system proposed by Linnaeus each species is given a unique name e.g. for horses it is caballus
  Related species are grouped into a genus e.g. for horses it is Equus
  So the name of the horse is Equus caballus


• Genera are placed in families.
  Families are grouped into orders.
  Orders are grouped into classes.
  Related classes are grouped into a phylum.
  We will look at seven phyla that affect agriculture.

• CLASSIFICATION
  Kingdom
  Phylum
  Class
  Order
  Family
  Genus
  Species


• CLASSIFICATION
  Kingdom
  PHYLUM
  CLASS
  ORDER
  FAMILY
  GENUS
  SPECIES


• HUMAN CLASSIFICATION
  Kingdom- Animalia
  Phylum- Chordata
  Class -Mammalia
  Order -Primatia
  Family- Hominidae
  Genus- Homo
  Species -sapiens
  Homo -sapiens

 

• Phylum Protozoa
  Single celled animals, microscopic.
  Protozoa that produce spores cause diseases in humans and animals.
  Babesia causes redwater fever in cattle and is transmitted by a blood sucking tick (Ixodes ricinus)
  The spores cause red blood cells to burst and haemoglobin is released and passed in the urine, hence redwater.

 

• Phylum Platyhelminthes
  This group contains flat worms, two groups of which are very important to Irish agriculture:
  –Flukes (See book pg. 250 -253)
  –Tapeworms (See book pg. 253)


• Control of Liver Fluke
  The liver fluke can be controlled in a number of ways:
  –Dose cattle/sheep with an anthelmintic which kills the flukes
  –Drain land to get rid of mud snail
  –Fence off wet areas to keep cattle/sheep away from infected areas
  –Use molluscicides to kill snails
  –Introduce geese to control mud snail population


• Phylum Nematoda
  Includes nematodes, eelworms and roundworms.
  Round, not segmented, elongated, pointed at either end and vary from a few mm to 15cm long.
  Life Cycle: eggs passed in faeces of host; hatch into larvae; larvae are eaten and cycle begins again.
  Important examples of nematodes are stomach and intestinal worms, lungworm and potato eelworm.


• Phylum Annelida
  Includes the earthworm, Lumbricus terrestris, and also leeches and marine worms.
  Earthworms are round, segmented and have four pairs of bristles on each segment.
  Earthworms feed on organic matter and excrete worm casts.
  They are very important for soil fertility and structure.


• Phylum Mollusca
  Slugs (no shell) and snails are the most important members.
  They contain a foot that secretes mucus used for crawling and they have a special tongue called a radula.
  Slugs tend to be a problem in horticultural crops where they eat the vegetation.
  Most important member is the secondary host of the liver fluke the mud snail, Lymnaea truncatula


• Phylum Arthropoda
  90% of all animals are in this phylum.
  They have an external skeleton, joined appendages and in order to grow they moult.
  Class Arachnida includes spiders, mites and ticks. These have two body segments and four pairs of legs. Mange mite and the sheep tick are the most important in this group.
  Class Insecta includes lice, fleas , aphids, cranefly (larvae is a leatherjacket) butterfly and clickbeetle (larvae is a wireworm). These have three body segments, three pairs of legs and usually two pairs of wings.


• Life Cycle of Class Insecta
  Complete metamorphosis:
  –Eggs -> larva -> pupa -> adult
  The larva is the feeding stage and the pupa is the resting stage. Some larvae are pests e.g. wireworm and leatherjackets eat crops.
  Aphids suck sap from plants damaging them directly and they may damage them indirectly by transferring virus diseases.

 

• Common Insect Pests and their Larva
  Insect: Crane Fly
  Larva: Leatherjacket
  Insect: Click Beetle
  Larva: Wireworm


• Parasites
  Parasites are species that live at the expense of other organisms.
  Ectoparasites live on the outside of the host and often have claws (lice) and sucking mouthparts (aphids, ticks) to hold on.
  Endoparasites live inside the host and have a special coating called a cuticle which protects them from the hosts defences e.g. fluke, tapeworms, hoose.


• Phylum Chordata
  Vertebrates are animals with a backbone and they belong to phylum Chordata.
  In this phylum are birds and mammals.
  Birds and mammals are the only warm blooded animals.
  This means their body temperature is independent of, and often much higher than, the surrounding environment.


• Birds – Class Aves
  Birds have wings, feathers and specially lightened bones.
  They do not have teeth but have a beak instead.
  In order to reproduce they lay eggs.


• Mammals – Class Mammalia
  Mammals have hair.
  Mammals give birth to live young.
  Mammals nourish their young in the womb via a placenta.
  When the young are born they feed on milk from the mothers mammary gland.
  Ungulates is a word to describe hooved animals.


• Dental Formulas
  Pig 3 1 4 3 Upper Jaw
  3 1 4 3 Lower Jaw
  Sheep 0 0 3 3 Upper Jaw,  3 1 3 3 Lower Jaw
  Rabbit 2 0 3 3 Upper Jaw
  1 0 2 3 Lower Jaw