Test 6 - Complex Animals - Arthropods

2025-07-29

What does artho mean

joint

what does poda mean

foot

What percentage of animals are arthropods

80%

What percentage of arthropods are insects

76%

Are arthropods closer related to humans or insects, why

insects because they are also segmented

6 classes of arthropods

Chilipoda, Insecta, Diplopoda, Arachnida, Maxillopoda, Malacostraca

Example of chilipoda

centipedes

example of insecta

all 6 legged

example of diplopoda

milipedes

examples of arachnida

spiders, mites, scorpians

Examples of maxillopoda

barnicles

examples of malacostraca

lobsters, shrimp, crab

Describe arthropod body cavity status and symmetry

coelomate, bilateral

Arthropods known to be the first animals to..

live in air

Describe athropod appendages

joint appendages, moveable legs, antennae, claws, mouthparts, etc, made of hard segments connected by flexible joints.

How are exoskeletons made

chitin secreted by epidermis

three body regions of arthropods

head, thorax, abdomen,

How do arthropods respire

body surface, gills, trachea, or book lungs

open or closed circulatory system

open

well developed sensory organs like…

compound eyes, trympanum (drum like ears), antenna (touch, smell & chemical reception)

Describe digestive system

complete, mouth, specialized organs, anus

dioecious or hermaphroditic

dioecious

internal or external fertilization

internal

describe nervous system

developed, doral brain connected by a ring and double ventral nerve cords

what environments do they live in

marine, freshwater, terrestrial, aerial

insecta exoskeleton made of..

chitin

insecta head segmented into…

6, with sensory antennae and compound eyes

insecta thorax with…

segmented legs & possibly wings

insecta abdomen segmented into

11 segments which house most of the digestive, respiratory, excretory, and reproductive systems

insecta respires through…

a system of internal tubes and sacs that lie directly next to the circulatory system, (tracheal system with spiracles)

insecta circulatory system…

is open

insecta: sexual or asexual, internal or external

sexual, internal

insecta: direct or indirect development

indirect: hatched from eggs, most as they grow in size

excretion through

Malpighian tubules

body cavity status of anthropods

coelomate

germ layers

3

symmetry

bilateral

nervous system?

brain, ganglia, ventral nerve cord

Malacostraca: head and thorax are often…

fused into cephalothorax

Malacostraca: what are maxillipeds

• Modified appendages near the mouth

• Help manipulate food and bring it to the mouth

Malacostraca: what are antennules

Small, paired sensory appendages on the head. Used for balance, smell, and touch

Malacostraca: difference between antennules and antennae

Antennules

• Shorter, usually paired first antennae

• Mainly used for balance (equilibrium) and chemical sensing (smell/taste)

• Often biramous (branched)

Antennae

• Longer, paired second antennae

• Primarily used for touch and sometimes smell

• Usually uniramous (single-branched)

Malacostraca: head includes…

6 segments with antennules, antennae, & mouthparts with appendages called maxillipeds

Malacostraca: 8…

thoracic segments (between head and abdomen, each segment bears a pair of legs, houses muscles and structures for locomotion and sometimes respiration)

Malacostraca also known as

crustaceans

Malacostraca: cephalothorax is almost completely covered by a…

carapace (part of exoskeleton)

Malacostraca: 6…

abdominal segments often used for swimming

Malacostraca: eyes are..

compound stalked or sessile.

(stalked eyes allow the crustacean to pull them in for protection or see in many directions, Mr. krabs)

Malacostraca: 5 pairs of…

walking legs, some with modified pincers

Malacostraca: 2 chambered…

stomachs

Malacostraca: central…

nervous system

Label all the parts of this decapod crab and list the functions.

Cheliped (claw/first leg) parts:

• Movable finger: Opens and closes to grasp or cut prey.

• Immovable finger: Fixed part of the claw; works with movable finger to pinch.

• Palm: Main gripping area; holds food or fights.

• Carpus: Joint segment allowing movement of the claw.

• Merus: Upper limb segment; provides strength and leverage.

Other Body Parts:

• Notched chela (claw edge): Helps grip slippery prey or dig.

• Antennae: Detects touch, chemicals, and vibrations in water.

• Eyes (compound, stalked): Wide field of vision; detect motion and light.

• Carapace: Hard shell protecting organs and gills.

• Abdomen (reduced & tucked under): Holds reproductive organs; helps in swimming for some species.

• Running legs (4 pairs): For walking and scuttling.

• Spines/claws on legs: Aid in digging, anchoring, and defense.

• Flattened leg tips: Adapted for swimming and digging into substrate.

Largest arthropod?

Japanese spider, leg span of 4 meters, 20 kg, life expectancy of 100 years

Ecological roles of arthropods

• pollination

• Production of honey, wax silk

• Recycled biological materials to aid in producing topsoil

• Part of food chain, (eat insects when food price is high)

• Forms symbiotic relationships with other organisms: burrowing shrimp and Goby fish, shrimp is blind and cleans and digs a burrow, Goby fish touches shrimp when danger approaches.

List the:

• class

• common name

• respiration methods

• circulatory systems

• digestive system

• nervous system

• reproductive methods and system

• habitat

For Hierodula patellifera

• Class: Insecta

• Respiration: Tracheal system (spiracles + tracheae)

• Circulatory System: Open

• Digestive System: Complete (mouth to anus)

• Nervous System: Brain + ventral nerve cord + ganglia

• Reproductive System: Sexual; dioecious; internal fertilization; lays eggs (ootheca)

• Habitat: Terrestrial; warm, vegetated areas in Asia

• Common Name: Giant Asian Mantis

List the:

• class

• common name

• respiration methods

• circulatory systems

• digestive system

• nervous system

• reproductive methods and system

• habitat

For Brachypelma hamorii

• Class: Arachnida

• Respiration: Book lungs

• Circulatory System: Open

• Digestive System: External digestion followed by sucking liquefied food

• Nervous System: Brain + ventral nerve cord

• Reproductive System: Sexual; dioecious; internal fertilization via male pedipalps

• Habitat: Terrestrial; burrows in dry forests/deserts of Mexico

• Common Name: Mexican Red-Knee Tarantula

List the:

• class

• common name

• respiration methods

• circulatory systems

• digestive system

• nervous system

• reproductive methods and system

• habitat

For Penaeus vannanei

• Class: Malacostraca

• Respiration: Gills

• Circulatory System: Open

• Digestive System: Complete (with stomach, digestive gland, intestine)

• Nervous System: Brain + ventral nerve cord + segmental ganglia

• Reproductive System: Sexual; dioecious; external fertilization; indirect development

• Habitat: Aquatic (marine); shallow coastal and estuarine waters

• Common Name: Pacific White Shrimp