insects are invertebrates!
living things are placed into groups depending on common characteristics.
The animal kingdom is informally divided into two groups, the vertebrates
and invertebrates. Invertebrates are a group of animals that
have no backbone, unlike animals such as reptiles, amphibians, fish,
birds and mammals who all have a backbone.
or taxonomy is a means of arranging living things into orderly groups.
These groups are mostly distinguished by structure and reflect evolutionary
relationships. Standardised categories allow quick recognition of
individuals and groups of similar organisms.
are 7 levels of classification, KINGDOM,
PHYLUM, CLASS, ORDER, FAMILY, GENUS and SPECIES.
highest classification level "KINGDOM' incorporates organisms that
share only a few important features. Modern taxonomy recognises
- Animalia (animals)
- Plantae (plants)
- Fungi (fungi)
- Procaryota (bacteria)
- Protoctista (algae, protozoans, slime moulds)
you move down through the levels, organisms are grouped into smaller
and smaller groups. Individuals within each group become more alike,
until you are left with a group of all the same type of organism
i.e. all the same species.
Groups at Each Level
other multicellular animals e.g. birds, mammals, worms, starfish
other arthropods e.g. insects, crustaceans, spiders, scorpions
insects e.g. grasshoppers, bugs, beetles, flies, butterflies
other Hymenoptera only e.g. bees, wasps, ants, sawflies
other ants, 95 Genera e.g. meat ants, green ants, sugar ants
members of this species only
95% of all animals on the earth are invertebrates of one form or
another. Invertebrates are found just about everywhere in both terrestrial
and aquatic habitats, and include animals ranging from sponges,
corals and seastars to insects, crabs and worms, just to name a
few. For information on collecting aquatic invertebrates in freshwater
environments see the Waterwatch
80% of all invertebrates are grouped into the single phylum Arthropoda
that includes spiders, crustaceans, centipedes, millipedes and insects.
All arthropods share the following common features:
segmented body and paired limbs
hard outer skin (known as an exoskeleton) with flexible
bilateral symmetry (meaning each side of the body is a mirror
image of the other)
remaining invertebrates consist of worms, slugs and snails.
Unlike arthropods these animals lack segmented legs and
are generally soft bodied.
are different from most other invertebrates. They are the largest
Class of organisms and account for over 75% of all animal species.
Insects can be separated from other invertebrates as they generally
have 6 legs and conform to a common body plan. This body plan comprises
of 3 parts, the head, thorax and abdomen although some parts may
be more distinct than others. Particular insect orders may have
some structures absent, reduced or greatly modified and some young
stages can appear very different from their mature adult form.
to identify insects?
you would like to identify insects then you must learn the parts
of their anatomy. There are three main parts which make up the body
of an insect, each having a specific role.
is designed for feeding and sensory purposes and consists of one
pair of compound eyes and up to 3 simple eyes, 1 pair of antennae
and mouthparts, which may be piercing, chewing or sucking types
depending on the insect.
is designed and is made up of 3 segments with each carrying 1 pair
of legs. In some adult insects the last two segments of the thorax
may support a pair of wings depending on the species.
is designed for reproduction. The abdomen is the largest and softest
of the 3 body parts. The abdomen houses all the organs vital for
insect survival such as respiration, digestion and reproduction.
Insects inhabit a diverse range of habitats, both terrestrial and
aquatic and this is often reflected by the great diversity in their
appearance. Most undergo some degree of change or metamorphosis
during their life cycle and young may not have all of the adult
insect features such as wings.
insects, such as silverfish show no change throughout their lifetime
except for an increase in body size. While other insects such as
bugs or grasshoppers go through gradual stages of development, each
successive stage (or nymph) is slightly more developed than the
previous one. For example wings begin to develop from small wing
buds and grow larger with each moult.
insects such as moths or beetles are typical of insects that undergo
a number of abrupt changes as they mature; egg - larvae - chrysalis/pupae
- adult. In insects such as these, the wings develop inside the
body and are visible only after the adult emerges from the pupal