Week One Flashcards
How many bird species are there in Wisconsin? Of these, how many migrate through? How many only winter?
331 species - 226 breed here, with 80 migrators and 30 wintering birds.
What are amniotes?
A clade that shares an amniotic egg, which is a series of fluid filled membranes. This characteristic is shared by mammals and reptiles.
What are diapsids?
“Diapsid” refers to holes in the temporal bones of the skull - diapsids have two. Synapsids, like humans, have one.
What happened to modern birds’ opening in the temporal bone of the skull if they are diapsids?
Over time, the orbital opening merged with the ancestral temporal opening.
What are defining features of archosauria?
A post-orbital opening, antorbital fenestre, one middle earbone (opposed to mammals’ 3), nucleated red blood cells (no nucleus in mammals), and a lower jaw with multiple bones (mammals have one).
What are archosaurs?
The common ancestor of crocodiles, birds, pterosaurs, and other dinos.
What are theropods?
Bipedal, mostly large, mostly carnivorous dinos. Several had fuzzy body covering.
What are maniraptors?
A theropod and ancestor of birds that evolved veined feathers and could “fly” somewhat.
What are aves?
Pretty recent (150 MYA) descendants of modern day birds. This group, archaeopteryx in particular, bridged the gap from dinos to birds.
What was archaeopteryx?
A fossil link between theropods and birds. It had teeth, a tail, but feathers and could fly.
What did archaeopteryx share with theropods?
Teeth, a long bony tail, unfused hand bones, flat sternum, and no alula.
What did archaeopteryx share with birds?
Hollow/pneumatic bones, a large furcula, and veined feathers.
What was unique or “intermediate” of archaeopteryx?
The presence of an intermediately sized brain case and the intermediate condition of the scapula.
Which lineages of archosaurs survive today?
Crocodillians and birds. Dinosaurs and many other theropods perished at the K-T boundary.
What is an alula?
A fused handbone in birds.
What is a uncinate process and what is it for?
An extension of bone on the ribs in modern birds, used for help with breathing, abdominal muscle function and stabiliziation in the face of shearing winds.
What are some features of extant birds?
Sustained flight, differentiated bills, and large external eggs.
How do birds perform sustained flight?
Weight reduction via less bones and hollow bones, high metabolism for an increase in power, and specially built to withstand the force of air.
What factors are associated with species diversity?
Latitude, topography, history of connections and isolations, ice sheets of the plestiocene epoch, structural complexity of habitat, and island isolation.
How does latitude affect species diversity?
Tropical areas support more species due to more energy availability and stable seasonality.
How does topography affect species diversity?
More complexity, both in the terrain and the habitat itself, supports more species.
How does energy affect species diversity?
More energy means more food being produced, which means more species the area can support.
Why are there more species in the tropics than at temperate latitudes?
There are three theories: more niches, more speciation without extinction, and the duration and extent of tropical environment’s over the course of earth’s history.
Why do eurasia and north america share so many long distance migrant waterfowl and shorebirds?
Because they were connect for much of their history! Some evidence for this is the fact that they share numerous related species.
