part 4

Which animal phylum is famously described by zoologists as dominating the Eumetazoans?

Phylum Arthropoda

What three environmental domains of nature have arthropods successfully occupied?

Land, sea, and air

What is the approximate number of discovered species in Phylum Arthropoda?

Over 1.2 million species

What is the estimated individual abundance of arthropods on Earth?

10^18 (1 billion billion) individuals

What are the three major evolutionary lineages of modern Arthropods?

Chelicerata, Myriapoda, and Pancrustaceans

Which two major taxonomic groups are nested together to form the Pancrustaceans?

Crustaceans and Hexapoda (insects)

What are the three core physical characteristics that drove the evolutionary success of arthropods?

A rigid exoskeleton, segmentation, and jointed appendages

Which specific cellular layer synthesizes and secretes the arthropod exoskeleton?

The epidermis

What polysaccharide polymer makes up the rigid structure of the arthropod cuticle?

Chitin

What materials are complexed alongside proteins to form a multilayered crustacean exoskeleton?

Calcium carbonate and chitin

What are two vital internal biomechanical functions of the rigid exoskeleton?

Provides physical protection and a surface for muscle attachment

What did the evolutionary combination of segmentation and a hardened cuticle allow arthropods to develop?

New mechanisms of locomotion and gas exchange

What is the primary evolutionary theme regarding arthropod body planning and regionalization?

Specialization of body regions (tagmatization)

What freshwater crustacean is used in the slides to demonstrate regionalized appendages?

The red swamp crayfish

What are the three main body tagmata regions identified on a typical crayfish diagram?

Head, thorax, and abdomen

What anatomical layout allows an arthropod's rigid appendages to bend and achieve complex movement?

They are jointed and moved by internal muscles attached to the exoskeleton

How does muscle attachment differ between a vertebrate endoskeleton and an arthropod exoskeleton?

Endoskeleton muscles attach externally to bone; exoskeleton muscles attach internally to the shell cuticle

What crucial physiological advantage did a chitinous exoskeleton provide for invading land?

Waterproofing (greatly reduces evaporative water loss on land)

Why did an aquatic exoskeleton naturally predispose early arthropods to successfully invade land?

It provided immediate physical stability to support walking on dry land without collapsing

What physiological systems control the complex process of molting in arthropods?

Hormonal and neuronal control systems

Which specific endocrine organ produces the ecdysteroid hormone responsible for initiating a molt?

The Y-organ

How is the old cuticle chemically prepared for shedding prior to ecdysis?

It is partially digested from underneath by specialized enzymes

What physical mechanisms do arthropods use to physically split open their old exoskeleton?

Uptake of water, air, or elevated blood pressure to make the body swell

Which marine macroinvertebrate was used as a structural case study for ecdysis from a biology journal?

The American lobster (Homarus americanus)

For what unique anatomical feeding structures are Chelicerates named?

Chelicerae

Name five major distinct animals that belong to the Chelicerata lineage.

Scorpions, spiders, myths, horseshoe crabs, and sea spiders

What are the two primary distinct body regions characterizing a chelicerate?

An abdomen and a cephalothorax

What is the structural role of chelicerae near the mouth of a chelicerate?

They are modified mouthparts clawed for grabbing and shredding food

How many pairs of walking legs do typical chelicerates possess on their cephalothorax?

4 pairs of walking legs

What specific chewing mouthparts near the opening of the mouth do chelicerates completely lack?

Mandibles

What are the two major sub-groupings of chelicerates described in the lecture?

Marine chelicerates and Arachnids

Give two examples of modern marine chelicerates provided in the slides.

Sea spiders and Horseshoe crabs

Into what functional structures are a spider's chelicerae modified, and what are they connected to?

Modified into fangs with associated poison glands

What ecological role do all spiders share?

They are predators

What specialized structures do most spiders use to manufacture silk strands?

Silk glands

What type of eyes do spiders possess, and what are they highly specialized at doing?

Simple eyes; they are better at detecting motion

What distinct vascular respiratory structures do spiders utilize for gas exchange?

Book lungs

Why are spiders ecologically valuable to humans and agricultural environments?

They are predators of insects, providing natural control over herbivorous pests

What are the tiny arachnids that are often parasitic or decomposers, alongside spiders and scorpions?

Mites and ticks

How does the body plan of a Myriapod differ from that of an insect?

It features two distinct body regions (a head and a trunk) instead of three

How many pairs of legs per body segment do centipedes have?

1 pair of legs per segment

How many pairs of legs per body segment do millipedes have?

2 pairs of legs per segment

What is the primary dietary difference between centipedes and millipedes?

Centipedes are carnivores; millipedes are herbivores/scavengers

Which group of Myriapods possesses poison claws to capture prey?

Centipedes

What group constitutes the dominant marine arthropods, boasting around 40,000 species?

The Crustaceans

Name the unique larval stage shared by crustaceans that possesses a median compound eye.

Nauplius larvae

What is the physical definition of a crustacean carapace?

A protective structural shield covering the head and thorax regions

What does the term "Decapoda" literally mean, and what familiar food items are included?

It means "10-footed"; includes lobsters, crabs, shrimp, and crayfish

What ecological and economic catastrophe struck the Alaskan Bering Sea snow crab fishery in 2021?

An historic metabolic collapse caused 10 billion snow crabs to completely disappear

Which small planktonic crustaceans are considered possibly the most abundant animals on the planet?

Copepods

What ecologically essential material do copepods generate that forms "marine snow"?

The production of sinking fecal pellets

Which crustacean sub-group represents the most structurally successful lineage to permanently invade land?

Terrestrial Isopods (sow bugs and pill bugs)

What unusual, highly modified marine crustaceans live a sessile lifestyle and filter-feed?

Barnacles

Which large claws on a lobster or crayfish are modified for defense and food capture?

Chelipeds

What are the small abdominal appendages that crustaceans use for swimming and carrying eggs?

Pleopods (swimmerets)

What does the term "Hexapoda" mean?

6 legs

What major evolutionary milestone did insects pioneer before any other animal group?

Powered flight

Describe the unique highly branched respiratory system utilized by terrestrial insects.

A system of air-filled tubes called tracheae that branch throughout the body

What are the external openings located on the surface of an insect's body called that allow air entry?

Spiracles

What are two major advantages of utilizing air as a respiratory medium instead of water?

Air is significantly less viscous, and it holds drastically more oxygen

What are two major physical or thermal disadvantages of living in an air environment?

Air is far less dense (no buoyancy) and features rapid temperature fluctuations

What structural system do insects use to execute nitrogenous waste excretion and osmotic salt regulation?

The Malpighian tubule system

Into what two broad structural categories are insects split based on their flight hardware?

Wingless insects and Winged insects

What is incomplete metamorphosis in winged insects?

Juveniles (nymphs) look like mini adults and lack wings

What is complete metamorphosis in winged insects?

Larval forms look completely different from adults and go through a pupa stage

What percentage of winged insect species undergo complete metamorphosis?

Approximately 85%

Name the four most familiar and hyper-diverse orders of insects that undergo complete metamorphosis.

Coleoptera, Lepidoptera, Diptera, and Hymenoptera

Which insect order consists of the beetles and represents the largest order of animals?

Coleoptera

Which insect order includes butterflies and moths, known for scale-covered wings?

Lepidoptera

Which insect order includes the true flies, mosquitoes, and gnats?

Diptera

Which insect order includes bees, ants, and wasps?

Hymenoptera

How does Monsanto’s genetically altered YieldGard corn destroy the destructive corn borer insect pest?

It contains a gene from Bacillus thuringiensis (Bt) that produces a toxin that ruins the pest's gut

What is the economic value range estimated globally for bee pollination services?

$235 - $577 Billion USD

What specific mechanical pollination behavior is performed by the native yellow-faced bumblebee?

Buzz pollination (sonication)

What negative reproductive impact do common neonicotinoid pesticides have on wild queen bumblebees?

Exposure hinders the development of eggs in the ovaries of spring queens

What organization is mentioned in the slides that focuses on the conservation of invertebrates?

The Xerces Society

What community science project maps bumblebees in the Pacific Northwest?

Pacific NW Bumblebee Atlas

What percentage of global crop species depend on animal pollination?

Roughly 75%

What structure do worker bees use to carry pollen back to their hives?

Pollen baskets (corbiculae) on their hind legs

What type of social structure do many Hymenopterans exhibit, featuring a queen and sterile workers?

Eusociality

What are insect wings structurally made of?

Cuticle outgrowths from the thorax (not modified limbs)

How many distinct body regions does an insect have?

Three: head, thorax, and abdomen

On which body region are an insect's walking legs and wings attached?

The thorax

What specialized mouthparts do true flies typically use to feed?

Sucking or lapping mouthparts

What chemical class of pesticides is explicitly named as a major threat to native bee populations?

Neonicotinoids

What name is given to the pupal stage of a butterfly?

Chrysalis

What role do insects play in food webs besides being pollinators?

Decomposers, herbivores, and a primary food source for birds and amphibians

What is the term for the shedding of an insect's exoskeleton between developmental stages?

Molting (ecdysis)

What are the developmental stages between molts in insects called?

Instars

Which order of insects is characterized by having only one pair of flight wings and a pair of halteres?

Diptera

What are halteres used for in flies?

Balancing organs that stabilize flight

What compound structures do insects use to form highly detailed, pixelated visual images?

Compound eyes

What are the individual light-receptive units that make up an insect’s compound eye called?

Ommatidia

Which type of insect camouflage allows them to blend perfectly into twigs or leaves?

Mimicry / Crypsis

What is the primary nitrogenous waste product excreted by insects to conserve water?

Uric acid

What structural feature helps aquatic insect larvae breathe underwater?

Tracheal gills

What structure do female insects use to deposit eggs into soil, plants, or hosts?

An ovipositor

What is the primary fuel source utilized by most insects to power long-distance flight?

Lipids or carbohydrates (trehalose)

Why does the small size of insects provide an evolutionary advantage?

Allows them to occupy tiny ecological niches and require fewer resources

What major evolutionary transition allowed insects to diversify exponentially during the Carboniferous period?

The evolution of wings and flight