Exam 3 - Biology of Animals

What clades are nematoda and nematomorpha in from most broad to most sepcific?

Bilateria, protostomia, and ecdysozoa

Ecdysozoans

Animals that molt a cuticle

Example of organisms in nematoda

Roundworms

Where can you find nematodes?

Freshwater, marine, and terrestrial

What method of feeding do most nematodes exhibit?

Parasitism

How many germ layers do nematodes have?

3

Organisms with 3 germ layers are…

Triploblastic

Organisms with 2 germ layers are…

Diploblastic

What does the placement of the mesoderm and coelom classify nematodes as?

Pseudocoelomates

What determines what type of “coelomate” an organism is?

Mesoderm and coelom

What type of cleavage do nematodes have?

Radial cleavage

Eutely

Fixed number of cells in the body

What is the outer body covering of a nematode?

Cuticle

What type of support does a nematode’s body have?

Hydrostatic skeleton

What structure in under the cuticle in nematodes?

Longitudinal muscles

What type of gut do nematodes have?

Complete gut

What are two structures in the nematode digestive system/gut?

Muscular pharynx and intestine

How do nematodes respirate?

Diffusion

How do nematodes circulate?

Diffusion

What processes are done by diffusion in nematodes?

Respiration and circulation

What structure(s) are in the nematode nervous system?

Dorsal and ventral nerve cords, sensory papillae, and amphids

Amphids

Anterior sense organs

Sensory papillae

Sense receptors

What structure(s) are in the nematode excretory system?

Gland cells

What do gland cells have on them in nematodes?

Excretory pore

Are nematodes monoecious or dioecious?

Dioecious

Copulatory spicules and what phylum they’re found in

Paired, needle-like, penis-like structures in nematodes

Where does fertilization occur in nematodes?

Internally

What’s significant about nematode juveniles?

They have four stages

Differences between males and females in nematodes

Females are longer/larger and have a vulva, uterus, and ovary; males are smaller/shorter and have a copulatory spicule, sperm duct, and testis

Examples of parasitic nematodes

Hookworms and trichina worms

Hookworm life cycle

Eggs are excreted as feces, first0stage juveniles develop in soil, juvenile penetrates skin that it comes into contact with, migrates through circulatory system to lungs, then migrates to the small intestine, where adults lay eggs and the cycle repeats

What disease to trichina worms cause?

Trichinosis

One of the largest known intracellular parasites

Trichina worm

Trichina worm life cycle

Infected meat is eaten by host, trichinae encysted in the muscles are released into the small intestine, adults mate and young trichinae are released into the circulatory system, where they migrate to the muscles of the host and encyst, cycle repeats

What type of body cavity is this?

Pseudocoelomate

Examples organisms in nematomorpha

Horsehair worms

Are nematomorphs ever free-living? When?

Yes, as adults

What organisms do nematomorphs parasitize?

Arthropods

How many germ layers do nematomorphs have?

3

What type of symmetry do nematomorphs have?

Bilateral symmetry

What clades are nematomorphs in from most broad to most specific?

Bilateria, protostomia, and ecdysozoa

What does the placement of the mesoderm and coelom classify nematomorphs as?

Pseudocoelomates

What is the outermost layer in nematomorphs?

Cuticle

What is underneath the cuticle in nematomorphs?

Longitudinal muscles (only)

What is a structure found in nematomorphs that most nematodes do not have?

Eye spot

What type of gut do nematomorphs have?

Vestigial complete gut

What processes do nematomorphs do through diffusion?

Circulation, respiration, and excretion

What structures do nematomorphs have in their nervous system?

Nerve ring

Are nematomorphs monoecious or dioecious?

Dioecious

How are female and male nematomorphs different?

Males have 2 caudal lobes; females have 3 caudal lobes

Caudal lobes in nematomorpha

Posterior structures that aid in mating

What structures are these and what phylum do they belong to?

Caudal lobes, nematomorpha

What is a synapomorphy of ecdysozoans?

Edysis

Ecdysis

The process of shedding the old skin or outer cuticle

What is a synapomorphy of nematoda?

Amphids

Amphids are found in what phylum?

Nematoda

What is a synapomorphy of nematomorpha?

Loss of gut (vestigial gut)

What clades is onychophora in from most broad to most specific?

Bilateria, protostomia, and ecdysozoa

What clades is tardigrada in from most broad to most specific?

Bilateria, protostomia, and ecdysozoa

Examples of organisms in onychophora

Velvet worms

Where can onychophorans be found?

Terrestrial

Are onychophorans predators or prey?

Predators

How many germ layers do onychophorans have?

3

What does the placement of the mesoderm and coelom classify onychophorans as?

Eucoelomates

What is the outermost layer of onychophorans?

(Thin, flexible) cuticle

How do onychophorans molt?

In patches

Structures in onychophorans outerlayer and head

Tubercles, sensory bristles, antennae, mandibles, and oral papillae

Tubercles in onychophorans

Small, wart-like bumps covering the cuticle

Oral papillae

Tasting sensory receptors

What type of gut do onychophorans have?

Complete gut

What are two structures in the onychophoran digestive system?

Muscular pharynx and salivary glands

Do onychophorans perform respiration through diffusion?

Partially

What is a structure in the onychophoran respiratory system?

Tracheal system

What is a structure in the onychophoran excretory system?

Nephridia

Nephridia

Kidney-like structures

Do onychophorans perform circulation through an open or closed system?

Open (circulatory system)

Open circulatory system

Circulatory fluid is pumped by a heart through short vessels and directly bathes organs in a cavity called the hemocoel

Closed circulatory system

A network where circulatory fluid is confined to vessels and separated from interstitial fluid

What is the nervous system like in onychophorans?

Ladder-like

What sense organs do onychophorans possess?

Oral papillae, simple eye, tasting spines, tactile papillae, and hygroscopic receptors

How do onychophorans deter predators and capture prey?

Slime (glands)

Are onychophorans monoecious or dioecious?

Dioecious

How can onychophorans reproduce?

Sexually, however one species can reproduce through parthenogenesis

What type of “-parous” are onychophorans?

Viviparous, oviparous, and ovoviviparous

Examples of organisms in tardigrada

Water bears

Where can you find tardigrades?

Freshwater, marine, and terrestrial

How many pairs of legs do onychophorans have?

14-43 pairs

How many pairs of legs do tardigrades have?

4

Two features of tardigrade legs

Unjointed and clawed

What is the outermost layer of tardigrades?

Cuticle

What does the placement of the mesoderm and coelom classify tardigrades as?

Only partially a eucoelomate

What type of gut do tardigrades have?

Complete gut

How do tardigrades feed?

Sucking fluids from plants or small animals

Three structures in the tardigrade digestive system

Mouth, pharynx, and needle-like stylet

What processes do tardigrades do through diffusion?

Circulation and respiration

What structures are in the tardigrade excretory system?

Malpighian tubules

What structures are in the tardigrade nervous system?

Brain, ventral nerve cord, and 4 ganglia on nerve cord

What sense organs do tardigrades have?

Pigment-cup ocelli and bristles

Are tardigrades monoecious or dioecious?

Dioecious