83 terms

Mammalogy Exam ppt 1 & 2

What characteristics are unique to mammals?
Hair, mammary glands, air moves into the lungs through negative pressure created by diaphragm, 3 bones in the middle ear, single lower jar bone
4 Types of skin glands
sweat, sebaceous, scent/musk and mammary glands
Sweat Glands
evaporative cooling and elimination of waste
sebaceous glands
lubricates skin and conditions hair/repels water
Scent and musk glands
chemical communication
mammary glands
modified sweat glands produce different % of protein, fat, and sugars in milk composition per species.
What is hair composed of?
composed of dead epidermal cells and keratin (protein)
What causes hair to stand up when we get goosebumps?
Arrector pili muscle
How can you tell different species apart by there hair under a microscope?
Cuticle scale pattern and medulla pigment ( porcupine vs muskrat)
An animals coat
Why is hair important?
Retains body heat and promotes absorption of ambient warmth (Insulation)
What commonly happens to hair once a year?
How does hair adapt to specific environments?
color, thickness and pattern adapt
What are 4 mechanisms pelage can perform?
Variation ( guard hair vs underfur), camouflage (zebra), countershading (black on top white on bottom) and communication( white-tailed deer)
maintain stable body temp through metabolic activity, fat storage, brown adipose tissue, shivering, huddling and nesting.
What's special about mammals circulatory system?
1) adaptations to avoid overheating, 2) separate systemic and pulmonary circulation
3)variation in heart rate across taxa.
How many chambers are in a mammalian heart?
4 which creates efficient O2 delivery.
Cellular respiration makes?
ATP which is energy, grebe cycle
why we cramp from lactic acid
Hemoglobin provides ?
amino acids are?
Building blocks of protein, 21 in a chain makes hemoglobin, each species is different
Respiratory System
Large lungs with many alveoli for greater gas transfer, air moves into the lungs through negative pressure created by diaphragm and expansion of intercostal muscles around ribs.
lay eggs
simplex uterus
Humans and other primates
bicornuate uterus
Uterine horns, Cats, dogs, and cows
duplex uterus
two cervices rabbits, rats, and mice
Penis with a bone
Scrotum with testes
allows sperm to mature at cooler temps than deep-body temp (descend at maturity or seasonally)
fetus develops in utero
Offspring that can walk, run, swim, and feed themselves at birth
Offspring that are completely dependent on parental care
Brain characteristics
Larger, well developed sensory, spatial ability, motor skills, learning, and intelligent language. Convolutions increase surface area and function.
vomeronasal organ
smell, flehmen Response
pinna, middle and inner ear
tactile ( rat)
Tapetum lucididum
vision, white shine in the eyes at night. (aardwolf)
incus, malleus, stapes
3 bones in the middle ear.
Mammal skeletons have become more simplified and
more completely ossified than other amniotes • fusion of bones
• greater flexibility of axial skeleton
• Well-defined articular surfaces (epiphyses) and points of muscle attachment (non-continuous growth)
• growth occurs in cartilaginous region between articular surfaces (metaphysis) until the shaft of the bone (diaphysis) is complete.
cursorial mammals
move fore-aft
mammalian jaw
single lower jaw bone ( Denatry)
change in genetic structure of a population through time "Descent with modification"
What is being modified in evolution?
Mechanisms of Evolution
mutation, genetic drift, gene flow, natural selection
changes in DNA that affect phenotype; must
occur in gametes to affect offspring
Genetic Drift
random, chance events that result in
differential survival of variants in the population
Gene Flow
movement of individuals into/out of population
Natural Selection
differential survival and reproduction
based on adaptations to particular environments
do not evolve
Natural Selection mechanisms
Individuals with characteristics that make them best suited to a given environment are more likely to survive and produce viable offspring with same genetic information
Natural Selection can only occur if there is?
Genetic variation, differential reproduction and heredity.
Genetic variation
selection can only act on variation that exists in the population
Differentail reproduction
those able to survive and reproduce will leave more descendences( with same genes)
the trait in question must have a genetic basis or it cannot be passed to offspring.
Individuals do not?
evolve structures they need to survive. If a variant already exists AND confers advantage, may be selected for.
relative genetic contribution an individual makes to future generations compared with other members of population
Reproductive Success
number of offspring an individual has that survive to reproduce. Male- variable RS and female predictable RS
Natural Selection does not?
not produce perfectly adapted species - adaptations need only to be good enough to improve fitness.
radiation (rapid speciation)
results in several species forming from one common ancestor
During the Devonian period of the PALEOZOIC era (400mya)
Tetrapods - ("four feet") descendants of lobe-finned fishes that emerged from aquatic habitats and walked on land (obligated to return to water to reproduce)
During the Mississippian period of the PALEOZOIC era (350mya)
Amniotes - some tetrapods developed adaptations that allowed reproduction on land by producing cleidoic eggs that protected embryo from desiccation
During the Pennsylvanian period of the PALEOZOIC era (300mya)
Temporal openings (fenestrae) were defining features for 3 main groups of amniotes:
anapsid skull
Turtles, no fenestrae (hole behind eye)
mammals, single hole on each side of the skull.
lizards, snakes, dinosaurs, crocodiles, and birds, two fenestrae
who split During the Pennsylvanian period of the PALEOZOIC era (300mya)
(gave rise to reptiles, dinosaurs, and birds)Synapsida (gave rise to mammals)
Synapsida ( mammals) split into?
Pelycosauraia and Therapsida ("mammal-like reptiles")
evolved from therapsids in the last Triassic period.
During the Triassic/Jurassic periods of the MESOZOIC era (200mya) Synapsids vastly reduced as?
dinosaurs proliferated during the Mesozoic era, but a few lineages of advanced synapsids (Therapsida) survived
early synapsid jaw articulation
quadrate and articular bones
later synapsid jaw articulation
cynodonts and early mammals), quadrate and
articular bones are reduced; jaw articulates with squamosal and dentary bones
what are the quadrate and articular bones now?
Still present, but functioned together with the stapes to transmit
vibrations to inner ear • In modern mammals,these bones are now the incus and malleus of the middle ear
During the Cretaceous period of the MESOZOIC era and the Tertiary (Paleogene) period of the CENOZOIC era (145-65mya)
dinosaur extinction, adaptive radiation of mammals (Paleocene epoch)
During the Jurassic and Cretaceous periods of the MESOZOIC era (200-150mya):
continental drift
late paleozoic era, little coastline, harsh fluctuating climate
late triassic and early jurassic (North)
late triassic and early jurassic (South)
continents continued to break apart
early Cretaceous
continents truly separate
Tertiary -
6 Faunal Regions
Nearctic, palearctic, oriental, neotropical, Ethiopian, australasian.
Mammals evolved from
Tetrapods, Amniotes, Synapsids, Therapsids, Cynodonts, Early mammals
derived traits
unique to given groups above but not present in previous ancestors below