Ornithology LECTURE test 2

Pigments

Chemicals that reflect some colors of light and absorb others

Melanin

Used by all organisms, produced by modifying an amino acid that is abundant in food —> produces blacks, browns and muted reds or yellows

Carotenoids

Obtained by eating foods that contain it, mostly seeds and plants but also aquatic invertebrates —> bright yellows, oranges, and reds

Porphyrines

Poorly known, in lots of tropical birds, modified from hemoglobin —> variety of colors including browns in owls

Structural colors

Produced by microscopic structures within skin or feather —> air filled chambers reflect green or blue depending on size

Stacks of melanin granules

Arrangement of stacks reflect color —> creates iridescent colors, color seen depends on angle of sun in relation to viewer

Origin

Point of attachment of a muscle that DOESN’T move when the muscle contracts

Insertion

Point of attachment that DOES move when a muscle contracts

Convergent evolution

2 unrelated organisms develop similar structures because they lead similar lifestyles

Mouth

Place where food enter the digestive system - food is chewed only enough to be swallowable

Bill/tongue shape

Highly modified to match diet (hinged upper mandible)

Rhamphotheca

Sensitive to touch and taste in some species

Crop

Bag formed by expanding esophagus - softens and stores food, regulates flow of food into digestive system

Proventriculus

Size varies with diet, chemical digestion - walls secrete acids and some digestive enzymes

Gizzard

Walls are very muscular to grind food and inner walls are lined with keratin often with small pebbles or sad embedded in it - act as molars

Small intestine

More digestion, main site of absorption - length varies with diet

Large intestine

Waste storage

Gastric cecum

Bag where SI and LI meet, extra space for absorption - big in plant eaters

Cloaca

Internal chamber where digestive, excretory, and reproductive systems all empty

Nitric acid

Most vertebrates, including birds, convert ammonia to this

Chorion

More control of H2O loss, along with inner/outer shell membrane

Yolk sac

Walls full of blood vessels, transfers proteins/nutrients from yolk and albumen to the embryo

Allantois

Walls full of blood vessels, carries out gas exchange and stores wastes