6: Ecdysozoans

what are the most species rich animal group?

ecdysozoans

what animals belong to the ecdysozoan clade?

crayfish, lobsters, barnacles, spiders, ticks, and insects

what are ecdysozoans covered by?

a tough coat called a cuticle (outer covering)

what does the cuticle do?

shed or molt thought a process called ecdysis

what are the 2 largest phyla?

nematodes and arthropods

what are nematoda?

roundworms

do roundworms have segmentation?

no

how do roundworms grow?

by periodically shedding their exoskeleton

what type of coelom do roundworms have?

a psuedocoelom

what are some species of nematoda?

plant and animal parasites

Trichinella spiralis causes…

trichinosis

Wuchereria bancrofti causes…

elephantiasis

elephantiasis is vectored by what ecdysozoans?

a microscopic filarial worm or mosquito bites (arthropod)

adult filarial worms cause…

inflammation of the lymphatic system leading to lymphatic vessel damage and lymphatic dysfunction

what is an important research development from ecdysozoans?

Coenorhabditis elegans

what ecdysozoans are the most diverse found in nearly all habitats?

arthropoda

what are characteristics of arthropoda ?

segmented bodies in 2-3 parts, hard exoskeleton, and jointed appendages

how do arthropods get their name?

bc they shed their exoskeleton

what animal is an example of an arthropod?

lobsters w 3 body parts: head, thorax, and abdomen

what are marine species of arthropods made of?

CaCO3 calcium carbonate

what are cuticles of arthropods made of?

polysaccharide chitin and proteins

what does the cuticle prevent ?

desiccation so they can live and colonize land

what are land species of arthropods special characteristic?

they’re waterproofed w/waxes

what enabled the first arthropods to colonize land ?

the cuticle

what does the exoskeleton limit?

growth and final body size

what must be shed for arthropods to grow?

the cuticle

do arthropoda have an open or closed circulatory system?

open

hemolymph

fluid that’s pumped in vessels and bathes tissues

what do phylum arthropoda not have?

blood pigments for carrying O2

gas exchange

CO2/O2

what do aquatic species of phylum arthropoda have for gas exchange?

hemolymph pumped thru gills/thin cuticles when in contact w/water

what aquatic arthropod has gills ?

crayfish

what do terrestrial arthropods have for gas exchange ?

tracheae and book lungs as respiratory organs

tracheal system

takes air directly to cells for gas exchange at cell lvl

what arthropod has book lungs and what’s their fxn?

spiders and their hemolymph flows through book lungs in contact w/air

what animals are examples of chelicerates?

arachnids such as spiders, scorpions, ticks, and mites

how do chelicerates feed?

using chelicerae

chelicerae

claw-like appendages (scorpions) or poisonous fangs (spiders)

what do chelicerates lack?

antennae

what do scorpions body consist of?

1 pair of pedipalps

4 pairs of walking legs

1 pair of chelicerae

pedipalp

feeding appendages used for sensing, defense, and reproduction

chelicerates can be either…

land predators or parasites

what parasites are chelicerates?

ticks and mites

what animals are examples of chelicerates?

black widows and brown recluse

what does the body plan of spider or tick/mite include?

cephalothorax and abdomen

cephalothorax

head and thorax

abdomen

reproductive and digestive organs

what do spiders and ticks/mites lack?

antennae

spiders are not the only arthropods that can make…

silk

spiders are the only arthropods that can…

catch prey with silk

what are myriapods body described as?

many identical segments and legs

what do myriapods use for feeding?

chewing mandibles

what’s significant of myriapods?

they have 1 pair of antennae and are all terrestrial

millipedes

detritivores/herbivores that have 2 pairs of legs each segment of their body

detritivore/herbivore

feed on plant detritus

centipede

predators that have 1 pair of legs per segment with a position claw

what animals are crustaceans ?

lobsters, shrimp, crayfish, krill, and barnacles

where do most crustaceans live?

mostly marine and freshwater but some live in land

how do crustaceans obtain food?

they can be predators, herbivores, scavengers, filter-feeders, and few parasites

scavengers

feed on dead creatures

what are the only arthropods with 2 pairs of antennae?

crustaceans

what do crustaceans feed with and how many legs do they have?

chewing mandibles and have many legs

what are the only invertebrates that have evolved flight?

insects

scientific name of fruit fly

drosophila

insects are hexapods meaning…

they’re six-legged and extremely successful on land

what are insects wings derived from?

cuticle extensions

what are insects 3 body parts?

head

thorax

abdomen

thorax contains…

bears 3 pairs of legs and 0-2 pairs of wings

head contains…

1 pair of antennae, compound eyes, and mouthpart

abdomen contains…

digestive and reproductive organs

compound eyes

independent photo perception units that allow for large view and detection of fast movement

what were the 3 pairs of legs adapted for in insects?

walking

jumping

grasping prey

digging in soil

paddling on water

what complex organ systems do insects have?

malpighian tubules

malpighian tubules fxn

excretion of metabolic waste

tracheal system fxn

gas exchange

what insects have protective color patterns and disguises such as modifications to antennae, wings, and bodies?

stick insects, leaf-mimic katydid, and caterpillars resembling bird poop

some insects have complex…

social systems

insects have a huge positive human/ecological impact for?

pollination of crops

food for wildlife

research

insects have a huge negative human/ecological impact for?

disease vectors

damage to homes

destruction of crops