Download Grasshopper Introduction

Grasshopper Dissection Introduction
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta (flies, grasshoppers, butterflies, beetles, and others)
Insects are by far the largest group of organisms on earth and probably include one to ten million
species. At least 70% of all known species of animals are insects, and they dominate all terrestrial
habitats. Three separate body regions and six thoracic legs are the major diagnostic features of
insects. Of course, insects possess all the major characteristics of arthropods, but their ability to
fly is probably the key to their great success. There are many advantages to being able to fly, such
as avoiding predators. While other groups of organisms can fly, insects were the first fliers. Most
insects have two pair of wings. However, insect wings are not modified appendages. Rather, they
are evaginations (outgrowths) of the thoracic exoskeleton.
The success of insects on land is further enhanced by an efficient respiratory system of tubes called
tracheae, which conduct air throughout the body. Insects also have highly modified mouth parts.
For example, mouth parts of grasshoppers grind coarse plant tissue, whereas mosquito mouth parts
form structures for puncturing and sucking.
1. Name the largest group of organisms on Earth: ___________________________
2. The two major diagnostic features of insects are:
1.
2.
3. The key to the great success of insects is their ability to ______________________
4. What are evaginations? _______________________________________________
All insects belong to the class Insecta, which is divided into orders. Scientists have now found
approximately 30 orders, but because insects are so numerous, unclasssified ones are found quite
often. As many as 750,000 different insects have been classified. Classification of insects is based
mainly on structure and number of wings, but number and shape of antennae, structure of legs, and
mouthparts are also considered.
The grasshopper is an excellent insect to study because it has characteristics common to many
insects, and it is large enough for easy identification and observation. Grasshoppers belong to the
order Orthoptera. Other orthopterans include crickets, katydids, locusts, and roaches. The
characteristics that set the orthopterans apart from other orders are their two sets of wings. The
forewings are parchment like and very stiff to protect the second pair of wings, which are
membranous. The other outstanding characteristic of this order is the extraordinarily muscular
hind leg, which is designated for jumping. This allows the grasshopper to leap up to 20 times the
length of its body.
5. To what phylum do the insects belong? _____________________________
To what class? _____________________________
Classes are subdivided into groups called _____________________________ of which there
are ____________ (a number) among the insects.
6. Name the order for the grasshoppers: _____________________________
7. Give two characteristics of this order:
1.
2.
Insects are mainly terrestrial animals and occupy almost every environmental habitat on land. The
development of wings gave insects such distinct advantages over other terrestrial invertebrates as
greater dispersal, access to more food supplies, and more efficient methods of escape from
predators. Insects have an exoskeleton composed of chitin. They have three pairs of jointed legs
and three distinct body regions. These regions are the head, thorax, and abdomen. Usually, two
pairs of wings are attached to the thorax. As members of the class Insecta, grasshoppers have one
pair of antenna and one pair of large compound eyes. They also have a tracheal-spiracle system
for gas exchange. The very efficient respiratory system of insects provides oxygen for the rapid
movement of muscles. The high reproductive capacity and relatively short reproductive cycle of
insects enables them to increase their populations at a rapid rate.
8. What does terrestrial mean? __________________________________________________
9. What is the exoskeleton composed of? Is this material a carbohydrate or protein?:
___________________________________________________________________________
10. How many pairs of legs are found on insects? ______ How many pairs of wings? ______
Grasshoppers live all over the world, mainly in open grasslands, weed patches, and roadside
growth, where they eat grasses and other leafy vegetation. The grasshopper exhibits gradual (or
incomplete) metamorphosis (definite series of changes during development) from the young
(nymph) stages to the adult. The grasshopper you will dissect is the Lubber Grasshopper (Romalea
microptera).
11. Grasshoppers are herbivores – this means they eat ______________________________
12. Define metamorphosis: ____________________________________________________
13. Give the name for a young grasshopper: ______________________________________
14. Give the scientific name for the grasshopper you will dissect: _____________________
15. Give its common name: _______________________________