Arthropod Characteristic Differences

Transcription

1 Subphylum Uniramia

2 Arthropod Characteristic Differences Subphylum Characteristics Representatives Uniramia Chelicerata Crustacea 1 pair of antennae uniramous legs tracheal system = spiracles, trachea and trachioles mostly terrestrial No antennae Fangs (chelicerae) Pedipalps (pinchers) 8 legs 2 pairs of antennae biramous legs legs attached to abdomen gills Millipedes Centipedes Insects Horseshoe crabs Spiders Ticks/Mites Scorpions Crabs Lobsters Shrimp Pill bugs

3 Uniramia Fossil Record!"#$#%&'$$()(*#+%,-./0$%1.2%34$"%,"#%+.,# '&%).5+%.-,"-'3'+$%6./0%(5,'%,"# 7.16-(.5 %+,-. Cambropodus 7.16-(.5!"#$%&'($)*%$

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5 How does the Subphylum Uniramia fit into the Arthropoda and Animalia? all other phyla other arthropods Largest arthropod subphylum Subphylum Uniramia Comprises 75% of all known animals

6 Uniramia Characteristics Most live on land Incredible evolutionary adaptation = can live where few metazoans can (oil swamps, sulfur springs etc) Close to 1 million insects described (20-50 million undescribed) Beetle family (65,000 species) largest Appendages multiarticulate Body with several tagmata Needless to say, in order to cover everything interesting and important you will need an entire course = Entomology

7 Uniramia: Gas Exchange by tracheal system (consists of thin-walled tubes) tracheal tubes open to the outside by spiracles if juveniles are aquatic, they may have gills spiracles

8 Uniramia: Circulatory System Semi-closed circulatory system consisting of tubular hearts (with openings = ostia) and a hemocoel (main body-cavity) filled with hemolymph (blood)

9 Uniramia: Digestive System Complete digestive system (straight) with regional specialization cuticle foregut midgut (where absorption of nutrients takes place) hindgut

10 Malpighian tubules: proctodeal evaginations Uniramia: Excretion

11 Uniramia: Reproduction sexual and dioecious usually internal fertilization Extensive larval development = including several developmental stages

12 Subphylum Uniramia Class Chilopoda aka the centipedes active predators = some with poisons body is slightly flattened dorsoventrally

13 Subphylum Uniramia Class Chilopoda 2 tagmata: head trunk Somite 1 pair of appendages on most somites 1 st somite has poison claws

14 Subphylum Uniramia Class Diplopoda millipedes generally herbivores + detritovores body is cylindrical

15 Subphylum Uniramia Class Diplopoda 2 tagmata: head trunk Somite 2 pairs of appendages on most somites

16 Subphylum Uniramia Class Insecta Most numerous and diverse group of the arthropods about 1 million described species, million still undescribed.

17 Keys to Insect Diversity Small size (can exploit more niches) Short generation time (adaptation can occur quickly) Metamorphosis Winged adults (dispersal) Adaptations to terrestrial environment (e.g. waterproof cuticle, tracheal system) Sophisticated sensory system Behavior and communication Co-evolutionary interactions with other organisms (e.g. mutualisms and parasitism)

18 3 tagmata: Subphylum Uniramia Class Insecta has 1 pair of antennae may have wings thorax has 3 pairs of legs may have 2 pairs of wings abdomen head

19 Class Insecta: Flight Some insects have both direct and indirect flight muscles (e.g. Orthoptera, Odonata): indirect muscles pull body wall down and lift wings direct muscles pull the wings down direct indirect

20 Class Insecta: Flight Some insects have only indirect flight muscles (e.g. Diptera, Hymenoptera). In these insects, the wings are moved by altering the shape of the thorax.

21 Class Insecta: Subclasses Insects are separated into 2 subclasses based on whether they undergo metamorphosis/develop wings. Subclass Apterygota - primitive insects that do not have wings Subclass Pterygota - insects that develop wings via 2 types of metamorphosis silverfish

22 Class Insecta Subclass Pterygota 2 types of Metamorphosis: Division Exopterygota Hemimetabolous (incomplete metamorphosis) Division Endopterygota Holometabolous (complete metamorphosis)

23 Class Insecta, Subclass Pterygota Division Exopterygota Hemimetabolous (incomplete metamorphosis) 5 ORDERS: Order Orthoptera Order Isoptera Order Odonata Order Hemiptera Order Homoptera

24 Class Insecta, Subclass Pterygota Division Endopterygota Holometabolous (complete metamorphosis) 4 ORDERS: Order Coleoptera Order Lepidoptera Order Hymenoptera Order Diptera

25 Ecology Insects are important pollinators Many flowering plants have evolved to exploit insects as pollinators Sexually deceptive orchids Extrafloral nectaries Many flowering plants have evolved rewards to attract pollinators (nectar) Nectar guides and displays to advertise these rewards.

26 Ecology Eusocial (truly social) insects (Hymenoptera and Isoptera) live in societies characterized by: Cooperative care of young Overlap of generations Polymorphism (caste system)

27 Symbioses Parasitism Parasitic insects are usually only parasites for part of their lives (e.g. mosquitoes). However, some insects are parasites for their entire lives (lice). Anopheles mosquitos transmit malaria Lice are ectoparasites of most birds and mammals

28 Symbioses Parasitoids Parasitoid larvae are parasites that eventually kill their hosts, while the adults are free-living.

29 Symbioses Mutualisms Some insects are involved in obligate mutualisms (both partners require one another). These are often plantpollinator relationships. Figs and fig wasps Yucca and Yucca Moths

30 Behavior Fungus gardening (leaf-cutter) ants Collect leaves and bring them back to nest The ants chew up the leaves, and inoculate the mash with enzymes from the hind gut which allow certain types of fungus to grow. The fungus is fed to the developing larvae.

31 Behavior Honey bees are capable of communicating the location of foraging sites to the rest of the colony by dancing. The waggle dance communicates the location and quality of distant food sources. The round dance communicates the location and quality of nearby food sources.