Vertebrates Pt. 4, Mammals

Mammals descended from __________ amniotes which had mammal traits

Cyodonts first appeared in the Late Permian 260 mya

synapsid

What two bones from the synapsid skull become the ear bones in modern mammals?

the articular and quadrate

4 unique traits of mammals

mammary glands secrete milk

hair or fur made of alpha-keratin

teeth vary in size, shape, and number

highly develped brain and complex behavior

4 additional unique traits of mammals

efficient respiratory and circulatory system

digestive tract adapted for multiple food types

sweat glands secrete 99% water for evaporative cooling

kidneys

Ribcage breathing in mammals is aided by the muscular ______, which improves negative pressure breathing

diaphragm

Lungs have masses of _________, which increase the surface area of the lungs in non-bird reptiles

alveoli

What is different about herbivore digestive tract?

large cecum and large colon with microbes

Mammals have a ____ chambered heart, which is a convergent trait they share with birds

4

egg-laying mammals

lay shelled eggs (oviparous)

young hatch and lap milk with no nipples

only echidnas and platypus

monotremes

maternal pouch

embryo starts growing in uterus with a placenta

fetus is born early and crawls to pouch

latches onto nipples to finish development

marsupials

only US marsupial

oppossum

have a better placenta for longer gestation

young are much more developed at birth

viviparous

eutherians

arboreal lifetstyle

hands and feet for grasping

large brains

eyes forward

flat face

Primates

What are the two arboreal groups of primates

lemurs and tarsiers

monkeys, apes, and humans

anthropoids

monkeys from africa

tails cant grasp and are mostly ground-dwelling

Old world monkeys

Not located in Africa

have prehensile tails

arboreal

New World Monkeys

What group of monkeys are most closely related to humans

Chimps: common ancestor about 7 mya

any many of the family Hominidae, includes living and extinct great apes, modern humans, orangutans, gorillas, chimps, bonobos

hominid

What is the only monkey considered to be a lesser ape

gibbons

How recently did homo sapiens exist?

200,000

only hominid still left

Homo sapiens characteristics

bipedal

ground dwelling

much larger brain

language

complex tools

How long have humans been in North America?

22,000 years

Humans are ____% genetically similar to one another

99

Cells that produce melanin and are responsible for regulating skin color

melanocytes

What AA is melanin a derivative of

tyrosine

Skin tones are relative to the position at the Earths _______

poles

genetically programmed and is based on the amount of pigment the skin contains without exposure to UVR

constitutive skin color

increased pigmentation seen as tanning following exposure to UVR

immediate tanning, hyperpigmentation

delayed tanning, increase in melanocytes

facultative/inducible skin color

Burning and peeling instead of tanning is a result of a defective ________ receptor which is necessary for melanin production

Mc1r

blackish brown pigment

eumelanin

reddish yellow pigment, fair skin and carrot-red hair

pheomelanin

B vitamin, essential nutrient

DNA replication and cell division, are influenced by UV light

intense sunlight halves the amount

folate

Who is more affected by folate deficiency?

light skinned people

fat soluble vitamin that maintains healthy immune system and builds healthy bones and teeth

Vitamin D

Who has skin that can produce more vitamin D?

light skinned people

dark skin people more vulnerable to vitamin D deficiency