PowerPoint Presentation

InsectaWeitian Sun and Paul Park

Classification and taxonomyKingdom: AnimaliaPhylum: Arthropoda Subphylum: HexapodaClass: Insecta

http://en.wikipedia.org/wiki/Insect2Phylogeny and evolution

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The evolutionary relationships of insects to other animal groups are still remained unclear . However, evolutionary evidence has emerged favoring closer evolutionary ties with crustaceans. And of course we can explore how insects were adapted to environment around them.3reproductionSexual: individuals develop from zygotes.

Asexual: individuals develop from gametes directly. example: Parthenogenesis

http://en.wikipedia.org/wiki/Insect_physiology45

Insects Developmentholometabolous insects complete metamorphosisgg -> hatch -> nymphs -> grow -> adult

hemimetabolous insectsincomplete metamorphosisEgg -> hatch -> nymphs -> grow -> adultholometabolousmetamorphosis

5(image from www.cals.ncsu.edu)There is two types of metamorphosis in insects, One is holometabolism and the other one is hemimetabolism.

Holometabolism is also referred to as complete metamorphosis. Holometabolous insects undergoes a series of changes in four stages. An holometabolous egg hatches and becomes a larva, and it forms pupa, and it becomes adult by undergoing ecdysis.

Hemimetabolism is also referred to as incomplete metamorphosis. Hemimetabolous insects undergoes a series of molts. Immature hemimetabolous insects are called nymphs. The appearance of nymphs are very similar to its adults, except for the presence of wings, which are not developed until its adulthood, as nymphs grow they become more similar in appearance to adult insects. And its adult does not undergo ecdysis.

Anatomy ExoskeletonThere are seven main parts of body: mouthparts, antenna, head, thorax, abdomen, legs and wings.

6Basic partHeadThoraxabdomen

http://www.entomology.umn.edu/cues/4015/morpology/7headNervous system Central nervous system: brain, sensory, motor, ventral nerve cord Peripheral nervous system: branches of axon from ganglia to muscle cell

9Defense and predation

Mimicry Aposematic colouration Crypsis Thick exoskeletonrepulsive odoursdisgusting tastes Irritating sprays Stingers Running or flying away

9Image from(www.flickriver.com)

Insects have ways to increase probabilities of succeeding predation or prevent predation.For example, by mentis mimicking leaves, it can hunt other insects without found by the hunting object nor its predator, like birds.There are more strategies of insects defense themselves or increase the probabilities of predation, they are Mimicry, Aposematic colouration,Crypsis, Thick exoskeleton, repulsive odours, disgusting tastes, Irritating sprays, Stingers, Running or flying away

Insects in ecosystem and human relationshipsoil turningAerationpest controlpollination wildlife nutrition

Image from (www.warrenphotographic.co.uk)

Insects play one of the most important roles in their ecosystems, which includes many roles, such as soil turning and aeration, pest control, pollination and providing wildlife nutrition.

We can classify insects as two different groups. One is beneficial insects and the other one is harmful insects.1011

Harmful insectsParasiticDamage structureDestroy agriculturesTransmit diseases

Malaria (mosquitoes)Typhus (lice)Plague (fleas)Yellow fever (mosquitoes)

11Harmful insects are also referred as pests.Those harmful insects are often adapted to be parasitic. Parasitic insects live in or out side of host body, and gain nutrition and protection from its host.

12Human perspectivehoney from bees (apiculture)silk from silkwormscross fertilization of cropsladybug (beetles)praying mantis

Ecological perspective important in food chains decompose dead animalPollinationParasitism

Beneficial insects

12Picture from (http://pakagri.blogspot.ca/2012/01/benefic-and-value-of-insects.html)

There are also insects that are beneficial to the environment and to humans.For example bees gather nectars from plants and provide honey.Silk worms provide silk, and so on.

From the ecological perspective insects are beneficial, since they provide a way of pollination, parasitism, decompose dead organism, and they plays important roles in food chains.Thank you for watchingReferencePicture from (http://pakagri.blogspot.ca/2012/01/benefic-and-value-of-insects.htmlImage from (www.warrenphotographic.co.uk)Image from (www.warrenphotographic.co.uk)Image from(www.flickriver.com)Source from (http://www.entomology.umn.edu/cues/4015/morpology/source from (www.cals.ncsu.edu)