Lecture 11: Animal Diversity 3 Flashcards
Arthropoda
“jointed feet”
invertebrates with an exoskeleton and jointed legs
Describe Arthropoda morphology
1) Appendages with JOINTS
2) Body SEGMENTED
3) External skeleton: EXOSKELETON (of chitin)
4) RESPIRATION uses tracheae (terrestrial), gills (aquatic), or book lungs (spiders, horseshoe crabs)
jointed appendage means
growth from the body of an organism that has a joint in it (elbow)
What are the three segmentations of Arthropoda?
Three fused segments:
1) head
2) thorax
3) abdomen
• Some have fused head + thorax (cephalothorax)
What are the benefits and drawbacks of the Arthropoda exoskeleton?
Benefits:
1) Muscle attachment
2) Protection
Drawbacks:
1) Vulnerable at times
2) Size limiting
An exoskeleton is a series of __________
tubes
structural strength of a tube __________ as tube diameter __________.
- decreases
- increases
As body size increases, so does…
- SURFACE area,
- SIZE of exoskeleton,
- & VOLUME increases.
How do arthropods deal with size limits?
molting
Molting allows for (3)…
- GROWTH,
- SHEDDING unwanted “stuff” (e.g., parasites, barnacles on crabs, etc.),
- and can even REGENERATE lost legs!
Four subphyla of Arthropoda
1) Crustacea
2) Hexapoda
3) Myriapoda
4) Chelicerata
Chelicerata includes…
scorpions, spiders, mites
Chelicerata includes…
scorpions, spiders, mites
First set of appendages of Chelicerate are modified into…
pincers or fangs
Chelicerata are mostly …
Mostly predatory but mites do almost everything (herbivores, predators, & parasites!)
Crustacea
dominant marine arthropods
Describe the morphology of the Crustacea
- each segment of thorax and abdomen usually has an appendage
- appendages may be branched
The first appendages of Crustacea and Hexapoda are …
antennae
Myriapoda
“lots of legs”
also have many segments (ie- millipedes and centipedes)
Hexapoda (largest subphyla)
“Classic” Insects
Hexapoda have (morphology)
1) Three body sections: head, thorax, abdomen
2) Six legs
_____% of all animals are arthropods.
85% -73% insects -12% OTHER ARTHROPODS 4% CHORDATES 11% OTHER PHYLA
How many described insect species are there?
close to 900,000
- Described vertebrate species ~ 38,000
- Described mammal species ~ 4,500
- Described insect species ~ 875,000
- Many undescribed insects: estimates of 2 million - 30 million(!!!)
Why have insects been so successful?
Insects are very successful
1) SMALL SIZE: habitat becomes more complex as you become smaller, allows more subdivision
2) FLIGHT: more movement and rapid colonization of plants
3) Complete METAMORPHASIS (change in body plan) during development
A majority of all animal species are insects with complete _________.
metamorphosis
metamorphosis allows…
change in body plan
allows SPECIALIZATION
-immatures specialize in
feeding and growth
-adults specialize in
dispersal and reproduction
immature insects specialize in…
feeding and growth