The Animal Kingdom…

To date we have recorded animals associated with the 4 following phyla. The arthropoda, the annelida, the mollusca and the chordata. We have also found numerous nematodes (round worms), which have their own phyla but currently we are unable to identify them…

The most diverse phylum on the planet. Includes spiders and insects. Very well represented in the Garden.

An abundant phylum that includes the earth worms. Under recorded in the Garden.

The slugs and snails of the Garden. An interesting and often persecuted group of animals.

The backboned animals, having a notochord defines this group of animals to which we ourselves belong.

What are Animals?

Plonk an animal in front of most people and they instantly and instinctively it seems, recognise it as being ‘Animal’. Be it a Lion, a Grasshopper or an Electric Eel. We just seem to know. However that is not to say there isn’t any bias involved.

When asked for an example of an animal, the first answer most people give will be something familiar, along the lines of a Cat or Dog. Less frequently perhaps a Bird, and rarely perhaps a Fish, Amphibian or Reptile. Some may give the name of more obvious ‘lower’ animals such as a Spider, Butterfly or Bee. Yet few would jump straight to a Slug or Flea despite them often being frequently encountered. Oddly, the least likely answer is often a Human, as many consider us to be above animal status or indeed any form of classification.

Defining the characteristics of animals is however very challenging. As although animals share many characteristics with other animals, these same characteristics are present in other non-animal forms of life. For example:

Animals are multicellular. This is true for all animals*. However, it is also true for Plants and Fungi. To confuse things further some single celled life exists in colonies so can also appear multicellular, such as Nostoc…

Nostoc. Our unicellular resident, looking distinctly multicellular as part of a colony

*To confuse things further, a group of organisms called Choanoflagellata, of which there are about 150 species, are both single celled / colonial AND regarded by many as Animals.

Animals are Eukaryotic. Ok, so this isn’t obvious, but it is rather important. In simple terms it means the cells in our body contain a membrane bound nuclei full of DNA. All animals share this characteristic, but then again so do Plants and Fungi.

Sexual reproduction. Ah yes, this will be it surely! Animals produce sexually. This shouldn’t need explanation but to clarify, this is two parent individuals of the same species, a male and a female, combining DNA to create offspring. But guess what! Lots of Plants and Fungi do this as well. And to confuse things there are animals that don’t produce sexually. But we won’t go into that for now.

The ability to move under their own power. Now we are getting somewhere! Animals all have the ability to move at some stage in their life cycle, although for a few species (but not ones regularly found in gardens) it is not at all obvious. Plants and Fungi lack this ability in the truest sense, although some plants can for example fling seed across a garden, so have a form of partial propulsion. However many single celled organisms also move about.

So what do Animals have, do or contain that is missing from all other forms of life. Well to be frank you need to start getting down into some serious microbiology here. One characteristic is a stage in the development of the embryo called the Blastula which is apparently unique to Animals. As is the production of collagen. Indeed, the aforementioned single celled Choanoflagellata are only considered by some to be animals because they can also produce collagen, suggesting perhaps that these organisms are an ancient reflection of a shared ancestor.

But we have digressed a bit. What we want to know is what “factor”, when stood in our Garden immediately identifies something as an Animal. Well, you never see a plant or fungi eating. But fungi are consumers (heterotrophs), as are some plants, and besides you don’t need to see an animal eating to know it’s an animal. Likewise with sleeping, although the definition of sleep is hard to pin down, you could argue that’s all plants and fungi appear to do.

The truth seems to be that we instantly recognise that an animal’s body has lots of different functional parts which we know means it’s an animal and many of these can move. If it has eyes, legs, wings, teeth or if it crawls, wriggles, flies or walks then it’s an animal. A distinct form of symmetry, where one half looks just like the other if you cut the animal in the right direction, is probably a subconscious factor when considered in combination with all this moving around.

Animal Classification

The Kingdom of Animals is broken down into groups of loosely related/similar creatures and these groups are termed Phyla. To date we have identified species associated with 4 such phyla. The first three containing the Arthropods, Annelids and Molluscs are all “Invertebrates” (they lack amongst other things a backbone). As indeed does a fifth phyla called Nematoda, which we also have records of in the garden but are yet to identify what species we have. The fourth recorded phyla are the Chordates which are the backboned animals “Vertebrates” to which we ourselves belong.

Click HERE for a better explanation of classification.

What are all these animals doing in the garden?

This is a difficult question to answer but becomes easier as we look at individual species or closely related species. For example, explaining what animals do in the garden would take some time, but explaining what spiders do in general terms is a little simpler.