Homework Answers
Windowbox gardens
The invertebrates (the little things that run our world)
Click on the tabs below, the list of phyla below left, the top ten below, the photographs, or use the Google search box at the top right of every page.
The invertebrates to be found in and around Torphins Wood, Scotland

home Animal kingdon Taxonomy Geological table definitions
 
Featured Phyla
Uniramia insects, millipedes, centipedes
Platyhelminthes flatworms, flukes, tapeworms
Mollusca snails, slugs, squid, octopus, clams, ship worms
Annelida worms, earthworms, leeches
Chelicerata spiders, harvestmen, mites, ticks, scorpions, horseshoe crabs
Echinodermata star fish, sea urchins, sea cucumbers, brittle stars, sea biscuits
Cnidaria, jellyfish, medusae, corals, anemones, sea fans, sea pens
Chaetognatha Arrow worms
Pentastomida tongue worms
Onychophora velvet worms
Tardigrada water bears
Nematoda round worms, hook worms
Crustacea crabs, shrimps, barnacles, water fleas, cyclops, woodlice
Nemertea ribbon worms
Chordata sea squirts, vertebrates
Nematomorpha hair worms
Porifera sponges
Ctenophora comb jellies & sea gooseberries
Pogonophora
Hemichordata
Brachiopoda lamp shells
Echiura spoon worms
Sipuncula peanut worms
Bryozoa moss animals, polyzoa, ectoprocts
Phoronida
Priapulida
Loricifera
Entoprocta
Acanthocephala spiny-headed worms
Kinorhyncha
Gastrotricha
Rotifera
Mesozoa
Gnathostomulida, jaw worms
Placozoa
choanocyte sponge cell Invertebrates make up 99% of animal life on Earth. On this site you will find descriptions and images of the various invertebrate phyla; just click on one of the top ten below, or the Animal Kingdom tab above, or the list on the left. Or if you are not sure where to look try the Google search at the top right.

The invertebrates are the little things that run our world. Because of our great size we tend not to notice them, but they were here long before us, and will be here long after we are gone (see my rant at the bottom of the page). And it would do our egos good to remember that without them we would soon die, but if all of us vanished tomorrow they would hardly notice.

In the average patch of Amazonian rainforest 93% of the dry weight of animal tissue is invertebrate according to Edward O. Wilson, the Harvard ecologist and ant expert.

A hectare of good quality soil has about 1000 kg each of earthworms and arthropods (uniramia, chelicerata) according to David Pimentel of Cornell University.

On the left the choanocytes of sponges.

January 2010 top ten pages
1 Porifera (sponges). On this page you will find drawings of the various cells (see the drawing of choanocytes above), characteristics of the different classes, and photographs of some species.
2 Compare and contrast. This page contains answers to some of the most common questions that come up in biology.
3 Homework answers. Definitions, brief notes, lists, essays.
4 Crustacea. Crabs, shrimps, barnacles, water fleas, woodlice, etc.
5 Hexapoda. The entry page to the insect pages. This pages contains general information and diagrams on the insect body - wings, legs antennae (see the drawing below of the different shapes of antennae) etc., as well as links to more detailed pages.
6 Platyhelminthes. The flatworms, flukes and tapeworms (see the head of a tapeworm below) - find out what's living inside of you!
7 Cephalopoda. Octopus, squid, nautilus - drawings (see the cephalopod eye below), photographs and text.
8 Animalia. An overview of the animal kingdom with diagrams (see below) , tables, etc.
9 Nematoda. Round worms, hook worms etc. Drawings and photographs and information about which of these parasites might be living in you (see the female hook worm at the bottom of the page), your pet, whales, and even in insects - nematodes are everywhere!
10 Cnidaria. Jelly fish, coral, sea fans, sea pens, medusae and anemones.

Animal Kingdom

Above a diagram showing the major division of the animal kingdom, and below the eye of a cephalopod.

Cepalopod eye

insect antennae

Above, just some of the many types of insect antennae

Global warming and pollution caused by us are having a real effect on the Earth. Species are going extinct in numbers higher than the normal background rate. However what is all this compared to Earth's past history which is measured in millions of years, while our recorded history is just a few thousand years, and as a species just a few hundred thousand years?

We are destroying the Earth as we know it, but we are not destroying the Earth. Nothing in human power can come close to the catastrophes the Earth has weathered in the past. Neither atomic bombs nor global warming at its worst will be as severe as the mass extinctions caused by the meteor impact in the late Cretaceous. This impact wiped out half the marine species it is estimated, as well as leading to the demise of the dinosaurs. Yet the earth recovered, and the small, hairy mammalian afterthought that was our ancestor prospered. Even this was as nothing to the huge catastrophe in the Permian, which is estimated to have caused the extinction of 95% of species. And the Earth went on and life continued, and species evolved.

So when we moan and groan about global warming and pollution it is OUR world we want to save. OUR species, OUR furry, feathery animals. The trees and plants WE like to look at and, smell and eat. And if we fail? Well many of them will go extinct along with us, but the Earth will go on. It will turn in its axis and the sun will rise. And life will go on. Some species will prosper in the new conditions, and other species will undergo changes, and divisions will occur and new species will emerge. Humans do not have the power to snuff out life, but we do have the power to snuff out species and change the world into something we cannot live in. So, do we keep this little paradise we have, or do we shuffle off and leave it to more adaptable species?
The choice is yours, isn't it?

Ascaris sp. female nematode in cross section

edible crab ventral

On the left a cross-section of a female hookworm, above the underside of a crab, and on the right the head of a tapeworm.

tapeworm scolex
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It is better to debate a question without settling it, than to settle a question without debating it. - Joseph Joubert 1754-1824.