Animals III Flashcards
1
Q
Ecdysozoan
A
-worm-like and legged invertebrates
-animals that molt (exdysis)
-monophyletic
precambrian
-oldest known land animals (scorpions f/ Silurian 437 mya)
2
Q
ecdysozoan epidermis
A
- secretes proteinaceous 3-layered cuticle that can be reinforced with chitin or CaCO3
- thin cuticles can pass gases, mineral, water, and food in parasitic forms
- thick cuticles reinforced with chitin make up exoskeleton of arthropods
- strong, waterproof provides support for muscle attachment
3
Q
pros and cons of chitinized cuticle
A
Pros
- protects organs
- prevents water loss
- supports organs and effects locomotion
- specialized appendaes
Cons -can't grow, so have to shed -molting is energetically expensive -newly molted animals are unprotected evolutionary constraint on size
4
Q
Ecdysozoan gps
A
Basal
- priapulids
- kinorhynchs
- loriciferans
evolved
- horsehair worms
- nematodes
- tardigrades
- onchophorans
- arthropods
5
Q
basal ecdysozoans
A
- worm like
- wingless
- thin cuticles
- direct development from egg to adult
6
Q
priapulids
A
- penis worm
- unsegmented animals with 3-part body (probiscus, trunk, and tail)
- live in mud and feed on slow invertebrates
- major predator in cambrian
7
Q
kinorhynchs
A
- mud dragons
- live in marine sands and muds
- basically microscopic
- bodies divided into 13 segments, each with separate cuticular plate
8
Q
loriciferans
A
- less than 1 mm
- divided into head, neck, thorax, abdomen
- covered by 6 plates
- mini versions found in cambrian
9
Q
nematoda
- feeding
- size
- segments
- coelom
- sex
A
- wormlike
- phylogenetic position is disputed
- 25,000 spp (prob 1 mil)
- free living or parasitic
- most microscopic–> biggest is 9mm
- unsegmented
- pseudocoelomate
- dioecious and parthenogenetic
- many plant, animal , and human parasites
- some extremophiles
10
Q
Nematode ecosystems
A
- represent 90% of all life forms on ocean floor and 80% of individual animals on the planate
- parasitic and saprotrophic
- some used as bio control agents against beetle grubs or other pests
11
Q
caenorhabditis elegans
A
important in genetic research
- Eutelic = has fixed number of somatic cells as adult
- genome is completely sequenced
- all cell lineages and every neuron mapped
12
Q
Nematode parasites
A
- Ascariasis = human intestinal parasitic disease from feces
- Filariasis = carried by mosquitos
- Dirofilaria immitus causes heartworm in dogs and cats
- Trichinosis = from eating raw pork –> common in undeveloped areas
- Enterobius vermicularis = pinworm –> most common human parasitic disease in developed countries –> from poop (often symptomless)
- Dracunculiasis (guinea worm disease)–> in copepods and water
13
Q
Onychophora and Tardigrades
A
- related to arthropods (have legs; not jointed)
- like arthropods, lost the coelom body cavity and instead have hemocoel for bathing organs
14
Q
Onychophora
A
- velvet worms
- segmented, but no jointed appendages
- cuticles with chitin
- tropical/temperate
- squirt slime to subdue prey
- live in social groups
- elaborate behaviors
15
Q
Tardigrada
A
- water bears
- microscopic
- found worldwide
- 4-layered cuticle
- extremely hardy
- cryptobiosis resting state (suspended animation)
- super weird genome
16
Q
Arthropods
A
Most divers group –> over 1 mil spp
- jointed legs
- versatile, protective exoskeleton
- segmentation
- tracheal gas exchange system (hex and myria) or book lungs (chelci)
- oldest land animals (437 mya) –> same time as vascular plants
- ightly developed sensory organs
- complex behaviors
- monophyletic and ancient
- biggest froup of animals (80% of all described)
- thick, chitin or CaCO3 exoskeleton
- successful terrestrially
17
Q
Arthropod gps
A
trilobitomorpha chelicerata myriopods crustaceans hexapods
