Lesson 5g. Phylum Arthropoda

Phylum Arthropoda

______ jointed foot

Phylum Arthropoda

_____largest phylum

• 900,000 species

• 75% of all known species

insects, spiders, crustaceans, millipedes scorpions ticks etc.

Phylum Arthropoda: 6

Phylum Arthropoda

______ most successful phylum

ecologically diverse

present in all regions of the earth

• adapted to air, land, freshwater, marine, other organisms.

Phylum Arthropoda: 3

Versatile exoskeleton

Efficient locomotion

Air piped directly to cells (terrestrial)

Highly developed sensory organs

complex behavior

metamorphosis

exoskeleton

Phylum Arthropoda reasons for success: 7

External: not developed by living tissue

protection

• secreted by underlying epidermis

• waterproof barrier

• chitin +/- calcium, lipoproteins

• modifications

Exoskeleton:

• can be site for muscle attachment

• energy stores- flying

• sensory receptors

• gas exchange

• bristles

Modifications:

exoskeleton

_____soft and permeable or hard, impermeable

exoskeleton

between segments of body/appendages = thin + flexible

exoskeleton

______must be shed (ecdysis = molting) to allow growth

exoskeleton

_____ relatively heavy

• limits size

Efficient locomotion

______ tagmatization, more specialized than annelids

• regions = tagma/tagmata

• jointed appendages

-Air piped directly to cells

• more efficient than most other invertebrates

• most have efficient tracheal system of air tubes; some breathe by gills -limits size

Highly developed sense organs

Sight, touch, smell, hearing, balance, chemical reception

Complex behavior patterns

• complex, organized activities

• may be innate (unlearned) or learned

Limited intraspecific competition

• many arthropods undergo metamorphosis

meta

_____= between/ after

morphe

_______= form

osis

_______= state of different stages (i.e. larva, adult) have different nutrition/ habitats

• no competition

Metamorphosis is a biological process that describes the transformation of an animal from one developmental stage to another. In arthropods, metamorphosis is a key factor that has contributed to their success. It allows them to exploit different niches, aids in dispersal, eliminates competition between larvae and adults for food and space, and helps in surviving harsh weather 1. Arthropods are the most successful group of animals, accounting for more than 80% of described animal species 2. A rigid exoskeleton is a common feature that is shared across the different groups of arthropods. The exoskeleton offers protection and is shed between developmental stages via a unique evolutionarily conserved process known as molting/ecdysis 2. Molting is triggered by steroid hormones, the ecdysteroids, and the regulation of their biosynthesis has long been proposed as a contributor to the success of arthropods during evolution 2. Juvenile hormones (JHs) are sequiterpenoids that were thought to be unique to insects, modulating the timing of metamorphosis in conjunction with the actions of ecdysteroids. However, it has been hypothesized that the sesquiterpenoid, methyl farnesoate (MF), had already est

What is metamorphosis and why has it contributed to arthropod success?

Phylum Annelida is the most closely related phylum to Phylum Arthropoda 1. This is because both phyla share a number of similarities, including a segmented body plan and the presence of jointed appendages 1

What Phylum is most closely related to Phylum Arthropoda?

clam, leech, elephant

Which of the following is not an arthropod? -beetle

• spider

• clam

• millipede

• caterpillar -leech

• elephant

Bilateral triploblastic schizocoelous no septa

Other characteristics of Arthropods:

Subphylum Trilobita, Chelicerata, Myriapoda Crustacea Hexapoda

Arthropod groups: 5

Subphylum Trilobita

_____ extinct trilobites

horseshoe crabs, spiders, ticks, mites and some extinct groups

Subphylum Chelicerata: 4

centipedes and millipedes

Subphylum Myriapoda: 2

crabs lobsters shrimps barnacles

Subphylum crustacea: 4

insects

Subphylum Hexapoda: 1

tri, lobos

Subphylum Trilobita ______ =three; ______= lobes

Subphylum Trilobita

_______ divided into 3 longitudinal regions

Subphylum Trilobita

________extinct

• oval, flattened

horseshoe crabs, spiders, ticks, mites, scorpions

Subphylum Chelicerata:

cephalothorax (prosoma)

____fused head and thoracic region

abdomen (opisthosoma)

______ contains digestive, reproductive, excretory, and respiratory organs

Subphylum Chelicerata

_____appendages attached to cephalothorax

Cephalothorax

_____pair of chelicerae (claw like feeding appendages)

Cephalothorax

______pair of pedipalps (usually sensing or feeding)

Cephalothorax

____four pairs of legs (5 in horseshoe crabs)

Subphylum Chelicerata

_____ no antennae most suck liquid food from prey

Spiders, ticks, scorpions

Class Arachnida: 3

Subphylum Arachnida

______most are harmless beneficial to humans

Subphylum Arachnida

_____most are predaceous.

Spiders

Some ______ (i.e., black widow, brown recluse spider) give painful, dangerous bites

Scorpions

_______ sting can be painful, dangerous

ticks, and mites

some ____ and ____ spread disease, cause irritation

Lyme disease

______ cause by tick

Order Araneae

what order is an spiders?

cephalothorax and abdomen

In spiders _____ and ____ shows no external segmentation

• tagma are joined by a narrow pedicel

Spiders (Order Araneae)

_____ all predaceous

• mostly insects

Chelicerae

______have fangs

Prey

_____ capture among the spiders

cursorial

Spiders (Order Araneae) some species are _______ predators

• stalk and ambush their prey

• they usually have well-developed eyes

• prey capture among the spiders

Spiders (Order Araneae)

_____ some are web-building spiders

• eyes not as well developed

• sensory hairs for detecting vibrations

Spiders

Many ____ (and mites) producing silk

• used for trapping prey, building nests, forming egg cases

silk glands and spinnerets

_____ that open to the exterior part of the abdomen through ______

Spiders (Order Araneae)

____ many species have evolved poison glands associated with the chelicerae

venom

spider _____ is used to subdue prey

• liquifies tissues with a digestive fluid

spiders

______ sucks up soupy prey (ewww!) -urban legends debunked

Myth

_____: Daddy longlegs (harvestmen) are one of the most poisonous spiders but their fangs are too short to bite humans

Daddy longlegs

_________: Order Opilionid

Order Opilionid

Daddy longlegs: ________

Order Araneae

Spiders: Order ______

Daddy longlegs

_____ one basic body segment (no pedicel)

Daddy longlegs

_____ don't produce silks

Daddy longlegs

_____ no venom, fangs

Spiders

_____ like most arthropods are dioecious

Pheromones Rituals

Mating habits of spiders: 2

Pheromones

_____chemicals that elicit behavioral change

Rituals

_____ males pluck females web (pattern is species-species)

Male spiders

______ builds small web, deposits sperm

• collects sperm in cavities of pedipalps

• pedipalps have ejaculatory duct + embolus

• inserts pedipalps into female genital opening

Male spiders: 3

egg spiders

______ laid in silk case

ballooning

Young spiders disperse by silk lines (_____)

• brown recluse

Phylum Arthropoda

what phylum is the crustaceans?

crusta

Subphylum crustacea ______ = shell

shell

crusta = ______

lobster crayfish shrimp crab water flea barnacles

The crustaceans: 6

the crustaceans

_____ mostly aquatic (mostly marine)

• a few terrestrial form

the crustaceans

_____major ecological and economical importance

Biramous appendages (at least primitively)

_______ - 2 main branches

the crustaceans

______ only arthropods with 2 pairs of antennae

the crustaceans

_____great specialization of appendages

• mouthparts chewing, grinding, handling

• appendages strengthen for walking or protection

List 3 differences between organisms of subphylum Celicerata and Subphylum Crustacea

Violin

______ shaped stripe on back

Necrotoxin

______- hemolytic

• Loxosceles reclusa

Lobster: A large marine crustacean with a cylindrical body, stalked eyes, and the first of its five pairs of limbs modified as pincers 12. Crab: A crustacean with a broad carapace, stalked eyes, and five pairs of legs, the first pair of which are modified as pincers 12. Shrimp: A small free-swimming crustacean with an elongated body, typically marine and frequently used for food 12. Krill: Small shrimp-like planktonic crustaceans that form a major component of the diet of many marine animals 13.

List 4 organisms that are crustaceans

coelom

Like other arthropods (+ unlike annelids), _______ is highly reduced

hemocoel

crustaceans have major body cavity is _______ (contains colorless blood)

Respiration

_________ - gills (usually)

• compound eye is typical of phylum

Size: Crayfish are much smaller than lobsters, typically ranging between 2 and 6 inches long, while lobsters can grow up to several feet in length 1. Habitat: Crayfish live in freshwater environments such as rivers and lakes, while lobsters live in saltwater environments such as oceans Color: Lobsters are usually greenish blue or greenish brown, but can be widely varied, while crayfish are usually dark blue, dark green, or black 1. Diet: Lobsters feed on small fish, snails, clams, mollusks, and other small crustaceans, while crayfish feed on insects, worms, and plants

What's the difference between a crayfish and a lobster?

crustaceans

______ same order, but different families

lobster

_______ are bigger

lobster

_____ are marine; crayfish live in freshwater creeks, ditches or lakes

Artemia salina

Brine Shrimp (_______)

Brine Shrimp

______ cosmopolitan

Brine Shrimp

______ restricted to highly saline lakes and evaporation basins

encased embryo

Dormant cysts = _________

Dormant cysts

__________ = encased embryo