Evolution of major groups of organisms Flashcards
(13 cards)
What did arthropods evolve from?
An annelid-like ancestor.
What is the structure of arthropods like?
Rigid, tubular exoskeleton, rigidity due to mineralisation, sclerotisation.
What are crustaceans?
Dominant marine arthropods.
What are characteristics of crustaceans bodies?
Segmented, divided into three regions, different appendages.
What did the jointed appendages of arthropods become modified for?
Antennae, mouthparts, prey capture, devices, gill bearing structures, egg laying, propulsive devices, silk spinning.
What are wings?
Flattened lateral extensions of the thorax.
Where are terrestrial crustaceans mainly confined to?
Damp places.
Why are insects, spiders and scorpions not restricted to certain environments?
Combination of sclerotisation and lipids.
What did the evolution of eyes play a key role in?
Massive diversification of animals that undoubtedly began in Precambrian but became evident by Cambrian.
How did visual predators provide strong selection pressure upon prey?
Evolve hard body parts, develop burrowing habit, modify modes of locomotion, evolve eyes.
Where do compound eyes occur?
In polychaete annelids but most developed in arthropods.
What are jumping spiders eyes like?
Simple, can be focused to form an accurate image, high acuity, multiple eyes, large visual processing region.
What are compound eyes made of?
Repeating units of ommatidia, each a separate visual receptor.
