Arthropods Flashcards
Protostome means _____ first.
Mouth
In most protostomes, the ______ ______ becomes the mouth.
Embryonic blastopore
All protostomes are ___________ symmetrical animals
Bilaterally
What are the two major traits exhibited by ALL protostomes?
- Anterior brain surrounds digestive tract entrance
2. Ventral nervous system with paired/fused longitudinal nerve cords
Ecdysozoans have an ______ skeleton, secreted by the underlying _______.
external,
epidermis
An ecdysozoan skeleton cannot ______.
grow
In order to grow, ecdysozoans must _____ the exoskeleton and replace it with a larger one.
moult
Onychophorans (velvet worms) are ______ but not _______.
Ecdysozoans,
Arthropods
Onychophorans have soft, fleshy, claw-bearing ________ legs. They have a thin, flexible cuticle that contains _______. The fluid-filled body cavities act as ______ skeletons.
unjointed,
Chitin,
Hydrostatic
Water bears/Moss piglets (Tardigrades) are _________ but not ________.
Ecdysozoans,
Arthropods
Tardigrades have eight, fleshy, unjointed legs and __________ skeletons.
Hydrostatic
Tardigrades lack both _______ and ___ _______ systems.
Circulatory,
Gas exchange
Tardigrades can survive for at least a ________ in a dormant state.
decade
Body segmentation arose in ________.
Annelids
Arthropods, and many other vertebrates have ________ legs.
jointed
Arthropods lost the ancestral ______. Their internal cavity has become a ______. (Onychophorans and tardigrades also have a type of _______.).
coelom,
haemocoel,
haemocoel
Appendages evolved in the ________ period, leading to the Arthropod’s (jointed foot) _______.
Precambrian,
clade
Trilobites flourished in the ______ and ______ seas before becoming extinct about 250 MYA.
Cambrian,
Ordovician
Trilobites had heavy _______. It was thickened by layers of protein and a strong, waterproof polysaccharide called _______.
exoskeletons,
chitin
Chitin restricts both ______ and ___ ________.
movement,
gas exchange
Exoskeleton limits ____. The strength of an exoskeleton increases as a square of the animal’s ____ _______. Both volume and weight ______ as the cubed power.
size,
linear dimensions,
increases
Centipedes have ____ pair(s) of leg(s) per segment.
one
Millipedes have _____ pair(s) of leg(s) per segment.
two
Chelicerates consist of three major clades, what are they?
Pycnogonids,
Horseshoe crabs,
Arachnids
The bodies of Chelicerates are divided into ____ major regions.
two
In Chelicerates, the anterior region bears two pairs of appendages, modified to form _______.
mouthparts
Many Chelicerates have ______ pairs of walking legs.
four
Pycnogonids are also called ______ _______.
sea spiders
There are ____ extant species of horseshoe crabs.
four
Most arachnids have a simple life cycle in which miniature adults hatch from ________ fertilised eggs.
internally
Other arachnids _____ their eggs during development and _____ ____ to ____ young.
retain,
give birth,
live
Mites and ticks are ______ for plant and animals diseases.
vectors
Many spiders produce ____ threads from which they spin webs to ensnare prey. Spider _____ are organs from which spider web silk is extruded. Pressure, as well as external pulling by the spider, rearranged the _______ ____ _______ _________ into a solid but flexible thread.
protein,
spinnerets,
liquid silk polymer molecules
Hexapoda is made up of? (4)
Collembola (springtails),
Diplura (Two-pronged bristletails),
Proturans (Wingless relatives of insects),
Insecta
Insects are the dominant terrestrial arthropods. They have bodies with ____ basic regions. Name and briefly describe them.
three,
a head, with a single pair of antennae attached;
a thorax, with three pairs of legs attached;
an abdomen with no appendages
Apterygota represent ____ groups of insects. Name them.
two,
Archaeognatha (the jumping bristletails)
Thysanura (Silverfish)
Archaeognatha do not have ______. They are ______ and after hatching, continue to moult throughout their life.
wings,
ametabolous
Pterygote insects were the first animals in evolutionary history to achieve the ability to _____.
fly
Paleoptera insects ______ fold their wings back against the body.
cannot
Neopteran insects _______ fold their wings back against the body.
can
Pterygotes have _______ pair(s) of wing(s), except in some groups in which _____ or _____ pair(s) of wing(s) have been secondarily lost.
two,
one,
both