Presentation is loading. Please wait.

Presentation is loading. Please wait.

Subphylum Crustacea: Aquatic Mandibulates

Similar presentations

Presentation on theme: "Subphylum Crustacea: Aquatic Mandibulates"— Presentation transcript:

1 Subphylum Crustacea: Aquatic Mandibulates
Phylum Arthropoda

2 Diversity Over 67,000 species worldwide
Live in aquatic environments (both ocean and freshwater) Can burrow, creep on bottom of ocean floor Some are sessile/permanently fixed (barnacles) Examples include: crabs, crayfish, lobster, shrimp, water fleas, brine shrimp, barnacle, daphnia, fish louse (parasite), krill, pill bugs (rollie pollies) Called crustaceans

3 Diversity Some are edible (lobster, shrimp, crayfish, crabs)
Others are parasites to other ocean-going organisms Fill a wide range of ecological roles and have enormous variation Food, bioindicators, etc Called Mandibulates Why? Because of the many pairs of sensory, chewing, food-handling appendages

4 Characteristics of Aquatic Mandibulates
Most have two body regions: 1) Abdomen Long narrow Tail region Includes the telson and uropod

5 Characteristics of Aquatic Mandibulates
Most have two body regions: 2) Cephalothorax fused head and thorax—chest region, appendages attached to this segment covered by a carapace Def: a cuticle composed of chitin, protein and calcareous material Used for protection but is very flexible Carapace covers most of the cephalothorax


7 Characteristics of Aquatic Mandibulates
Appendages All appendages are biramous (two main branches) First two pair: Antennae (2 pair – this distinguishes them from all other arthropods) Next pair: Jaw-like mandibles Used to chew and crush food Maxillae Used to hold food

8 Characteristics of Aquatic Mandibulates
Appendages, cont. Three pairs of jaw feet called maxillipeds Used to touch, taste and handle food Claws for catching food One pair of walking legs for each segment (four pairs total) Swimmerets on the abdomen Used for swimming and to catch sperm


10 Characteristics of Aquatic Mandibulates
Respiration Gills (if present) Some use diffusion for respiration Segments Most have segments (some have more) Nervous System Nerve cord on ventral side that swells to ganglia Digestive system Digestive gland mixes food with digestive enzyme Stomach, intestines, anus

11 Characteristics of Aquatic Mandibulates
Excretory system Green gland—regulates amount of salt in body Reproduction Gonopores—pores that release reproductive cells The position of these varies according to sex Location: at the base of a pair of swimmerets or on segments without legs

12 Classification Subphylum Crustacea Class Remipedia Class Cephalocarida
Fairy shrimp Subphylum Crustacea Class Remipedia Class Cephalocarida Class Branchiopoda Orders: Anostraca (Fairy Shrimp, Brine Shrimp), Notostraca (tadpole shrimp), Diplostraca (water fleas, clam shrimp) Brine shrimp Tadpole shrimp Water flea

13 Classification Subphylum Crustacea, cont. Class Ostracoda
Fish lice Subphylum Crustacea, cont. Class Ostracoda Class Maxillopoda Subclasses: Copepoda, Tantulocarida, Branchiura (fish lice), Cerripedia (barnacles) Class Malocostraca Orders: Isopoda (pill bug), Amphipoda, Euphasiacea (krill), Decapoda (shrimps, crabs, lobsters) Copepods

14 Classification Decapods (Order Decapoda)
Crayfish, lobsters, shrimp, crabs 10 walking legs Carnivores Eyes on stalks first three pairs of appendages modified for eating

15 Classification Isopods (Order Isopoda) Pill bugs, sow bugs
Feed on dead, decaying matter Obtain oxygen from air/moist soil no carapace eyes are not stalked gills on appendages

16 Classification Cerripeds (Subclass Cerripedia) Barnacles
Shelled, sessile No eyes, gills, heart or blood vessels Giant Barnacles

17 Classification Copepods Smallest in size Plankton, Krill Feed on algae
No gills or abdominal appendages

18 Crayfish External Dissection

19 Crayfish Characteristics
General Characteristics freshwater aquatic invertebrate typically 6 to 8 cm in length, may be as long as 12 cm jointed exoskeleton body consists of cephalothorax and abdomen

20 Crayfish Characteristics
General Characteristics, cont. paired, jointed appendages head has 2 pairs of antennae, 1 pair of mandibles, and 2 pairs of maxillae undergoes ecdysis (shedding of the exoskeleton to accomplish an increase in body size)

21 Crayfish Characteristics
Digestive System The digestive tract consists of: 1) the foregut, includes an enlarged stomach (grinding) 2) the midgut 3) the hindgut (functions in water and salt) regulation. 4) anus 5) digestive gland secretes digestive enzymes and aids in the absorption of the products of digestion.


23 Crayfish Characteristics
Excretory System Excretory organs are called the antennal glands They excrete the waste products of blood filtration; Ammonia is the primary waste product. Ammonia is also excreted across the gill surfaces and by diffusion across thin parts of the exoskeleton.


25 Crayfish Characteristics
Respiratory System Use gills The gills are located in between the carapace (the exoskeleton of the cephalothorax) and the body wall. Circulatory System The circulatory system of the crayfish is centered around a muscular heart


27 Crayfish Characteristics
Nervous System The crayfish nervous system is composed of a ventral nerve cord Concentrated ganglia (anterior end) Giant neurons in the ventral nerve cord function in escape responses.


29 Crayfish Characteristics
Endocrine System The endocrine glands Release hormones into the blood The hormones control functions, such as ecdysis, sex determination, color change and regulation of heart rate

30 Crayfish Characteristics
Sensory Structures Chemoreceptors Tactile receptors function in equilibrium, balance, and position senses Statocysts functions in movement and orientation Ocelli (simple eye) allows larvae to go toward or away from light does not form images Compound eyes mounted on moveable eyestalks lens system made of 14,000 individual receptors

31 Crayfish Characteristics
Sexual Characteristics and Reproduction Crayfish have separate sexes. Mating occurs just after the female has molted (usually in the spring). Once they leave their mother, they begin an adult life and reach maturity in anywhere from a few months to a year. The average life span for a crayfish is two to three years.

32 Crayfish Internal Dissection
Another dissection

33 Crayfish Characteristics
Predator / Prey Relationships Feed on living animals and plants, Also consume a fair amount of dead plants, dead or dying animals, and detritus. Crayfish are omnivores. Crayfish do not prey on larger animals, such as fish

34 Terrestrial Mandibulates: Spiders and Insects
Phylum Arthropoda

35 Characteristics Segmented bodies Jointed appendages Exoskeleton
Specialized for eating, sensing, reproduction, defense and movement Exoskeleton Hard covering on the outside of the animal Limits the growth of the organism (must shed) Muscles are attached to this layer Secreted by underlying epidermis Shed (molted) at intervals

36 Characteristics Bilateral symmetry Muscular system Body cavity Complex
Contains two types of muscles Body cavity Coelom is smaller in size   Most of body cavity consists of hemocoel (sinuses, or spaces, in the tissues) Filled with blood

37 Characteristics Digestion Circulatory System Complete digestive system
Esophagus, crop, gizzard, midgut, hindgut and anus Mouthparts modified from appendages and adapted for different methods of feeding Circulatory System Open system Dorsal contractile heart, arteries

38 Characteristics Respiration Obtain oxygen through:
1) body surface (diffusion), 2) gills, 3) tracheal (air tubes) – carry oxygen to muscles 4) book lungs Spiracles—small openings in the exoskeleton through which air opens

39 Characteristics Water retention—3 structures 1) Malpighian tubules—
excretory structures that remove metabolic wastes from blood and return water to the cells 2) Exoskeleton— prevents water evaporation 3) Book Lungs— gas exchange without water loss (also used in respiration)

40 Characteristics Excretory system Paired excretory glands in some
Same as the nephridial system of annelids  Some with other excretory organs, called Malpighian tubules

41 Characteristics Nervous system
Contains same system of annelid (with dorsal brain connected by a double nerve chain) Fusion of ganglia in some species   Well-developed sensory organs Compounds eyes with many lenses (can see motion and color)

42 Characteristics Reproduction Sexes usually separate,
Paired reproductive organs and ducts;   Usually internal fertilization; often go through metamorphosis (change in body form  larva to adult)

43 Classification Phylum Arthropoda (most diverse phylum)
Subgroups of Terrestrial Arthropods: Subphylum Chelicerata – Characteristics of all: six pairs of appendages that include a pair of chelicerae, a pair of pedipalps, and 4 pairs of walking legs No mandibles and no antennae.   Suck up liquid food from their prey. Two body segments (abdomen and cephalothorax)

44 Classification Class Merostomata –
Horseshoe crabs are practically unchanged Have an unsegmented, horseshoe-shaped carapace, and a broad abdomen, which has a long spine like telson. Book gills are exposed.   They feed at night on worms and small mollusks and are harmless to humans. Include horseshoe crabs

45 Classification Class Arachnida – over 50,000 species
Body organization: cephalothorax, abdomen Examples: Spiders (35,000 species), scorpions, ticks, mites

46 Classification Spiders: Scorpions: Mites and Ticks:
hunt using strong legs and good eyes; weave silk for web (hunt and reproduction); fangs are modified chelicerae (liquefy prey with venom) Scorpions: long, segmented abdomen with a stinger; Mites and Ticks: mites have one body segment, eat bacteria or skin cells of humans; ticks are mostly parasitic, require blood before molting and can cause Rocky Mtn spotted fever

47 Classification Subphylum Uniramia – Characteristics:
Appendages are unbranched.   Includes the insects and the myriapods (centipedes and millipedes). Heads resemble the crustacean head but have only one pair of antennae, instead of two. Also have a tympanic membrane for sound  Have mandibles and two pairs of maxillae Respiration is by body surface and tracheal systems, Although juveniles, if aquatic, may have gills.

48 Classification Class Chilopoda -
They are active predators with a preference for moist places such as under logs or stones, where they feed on earthworms, insects, etc.   Each segment (they have between 10 and 70), except the one behind the head and the last two, bears one pair of appendages. Include: centipedes

49 Classification Class Diplopoda – Include Millipedes
Have cylindrical bodies made up of 25 to 100 segments. Abdominal segments each have two pairs. Millipedes are less active than centipedes Generally herbivorous, living on decayed plant and animal matter

50 Classification Class Insecta –
Most numerous and diverse of all arthropods. (There are more species of insects than species in all the other classes of animals combined!!) Have three pairs of legs Usually have two pairs of wings (although some have one pair of wings, or none)   Body organization: head, thorax, and abdomen. The head usually bears a pair of large compound eyes, a pair of antennae, and usually three ocelli.  

Download ppt "Subphylum Crustacea: Aquatic Mandibulates"

Similar presentations

Ads by Google