Term
| General features of mammals! (5) |
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Definition
1. All have hair even if extremely reduced
2. most have a specialized placenta and mammary glands to feed the embryo and newborn
3. They are endotherms so they can live in many areas
4. Most have specialized teeth and jaws
5. Their nervous system is more advanced than in other groups (except for birds)
- also they interact with humans more than any other group |
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Term
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Definition
| a reptile with a single lateral opening behind the orbit, the only surviving ones are mammals |
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Term
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Definition
| the only synapsids that survived, appeared 280-240 million years ago…. They required upright limbs under their body, they need to get advanced muscular coordination for their upright limbs (have to acquire better coordination and balance) |
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Term
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Definition
| – they had high metabolic rates (know this from the fossil record), better jaw musculature, differentiated teeth (heterodont teeth), a secondary bony palate… helpful when you’re a baby and want to breathe and suck at the same time, they have ribs, a diaphragm etc. |
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Term
| Early mammals were probably ectotherms or endotherms? |
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Definition
| endotherms! They know this from the fossil record by evidence of the growth rate of bones |
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Term
| What happens to skin that is subject to abrasion? |
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Definition
| the outer layers become thicker and keratinized (example our heels) |
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Term
| What are the functions of hair? |
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Definition
1. Thermal insulation
2. Protection
3. Concealment
4. Waterproofing and buoyancy
5. Signaling
6. Sensory |
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Term
| What are the two main kinds of hair? |
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Definition
underhair - insulates --> warm, soft and traps layers of air
guard hairs --> protect against wear and provide coloration |
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Term
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Definition
secrete a watery fluid found in hairless regions
- it is thermoregulatory in function --> drws heat away from the skin surface |
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Term
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Definition
develop at puberty and open into hair follicles
- they secrete a mix of salt, urea and water
- may correlate with reproductive cycles ex: gland under your arms
- convoluted and large
- stinky |
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Term
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Definition
mostly found around the face, feet and anus
- involved in communication with conspecifics
- marking territory
warning and defense
attraction of mates |
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Term
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Definition
| produce and oily sebum that keeps skin and hair pliable and glossy - usually found all over the body |
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Term
| Mammary glands are most likely related to what type of skin glands? |
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Definition
| apocrine skin glands... they have similar developmental patterns |
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Term
| Why do males have nipples? |
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Definition
| Because the nipples are present/in place in both males and females before development starts |
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Term
| Though mammary glands may look different in all mammals, what is their function for all? |
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Definition
| they secrete milk via nipples or teats to feed the babies! |
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Term
| What is characteristic about mating of rabbits, ferrets and mink? |
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Definition
| they are induced ovulators... which means copulation causes ovultation so the odds of success are very high |
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Term
| Describe reproduction in Monotremes (ex: duck-billed platypus) |
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Definition
They are the only egg laying mammals
They only have on breeding season per year
They build a nest or abdominal pouch where the egg is incubated then they hatch into helpless/hopeless babies
- they nurse from their mothers at an opening in their fur |
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Term
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Definition
| the primitive yolk sac in marsupials |
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Term
| Describe reproduction in marsupials |
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Definition
they are pouched, viviparous mammals that give birth to very underdeveloped young
- after fertilization the embryo is encapsulated by shell membranes and floats free for several days
- after they hatch, instead of "implanting" the embryo erodes a shallow depression in the uterine wall where they lie and absorb nutrient secretions from the mucus from their vascularized yolk sac |
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Definition
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Term
| lazyyyyy see slide 11 of mammals |
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Definition
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Term
| how many cervical vertebrae to mammals have? |
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Definition
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Term
| What is the function of the 1st two cervical vertebrae? |
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Definition
| they are modified to support the skull and permit pivoting |
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Term
| As animals become larger what happens to their bones? |
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Definition
| they become more upright and they eventually thicken |
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Term
| What occurs as a result of changes in jaw articulatoin? |
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Definition
| the quadrate and articular bones migrate to the middle ear (incus and the malleus) |
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Term
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Definition
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Term
| Types of heterodont dentition: Incisors |
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Definition
| sharp edges for snipping or biting |
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Term
| Types of heterodont dentition: Canines |
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Definition
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Term
| Types of heterodont dentition: Premolars |
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Definition
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Term
| Types of heterodont dentition: Molars |
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Definition
| for crushing and grinding |
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Term
| Some animals have one deciduous set and a permanent set... which types fall under each respective category? |
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Definition
deciduous --> incisors, canines and premolars
permanent --> molars |
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Term
| Insectivores (give an example and define) |
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Definition
shrews, moles, anteaters and most bats
they eat little fibre and have a short digestive tract |
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Term
| Herbivores (ex and define) |
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Definition
grazer examples: horses, deer, antelope
gnawer examples: rodents, rabbit and hares
- have a high fiber diet and a long digestive tract |
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Term
| How do herbivores handle their high fibre diet |
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Definition
| anaerobic fermentation of cellulose, ceca and by eating fecal pellets |
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Term
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Definition
feed on herbivores
they are specialized to kill prey which requires intelligence and organized behaviour
short digestive tract |
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Term
| Omnivores (ex and define) |
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Definition
pigs, racoons, rats, bears, most primates
- primarily carnivores but will switch to plants when normal food is scarce |
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Term
| Do small or large animals eat more per unit size? |
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Definition
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Term
| In hot climates how do small animals thermoregulate? |
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Definition
| they live underground or are nocturnal |
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Term
| How do large animals thermoregulate in hot climates? |
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Definition
pale fur
concentrate fat in humps
allow body temperature to drop at night and rise during the day
ps... some mammals have large extremities to get rid of heat |
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Term
| In cold climates, how to mammals thermoregulate? |
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Definition
increase insultation and/or heat production --> shivering
their fur becomes thicker in winter
Limbs cool near freezing
Small mammals store food and live under snow |
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Term
| depending on size animals in cold climates may enter daily torpor, hibernation or go into a prolonged deep sleep |
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Definition
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Term
| where is the heart in mammals? |
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Definition
| in the thorax and it is covered by pericardium |
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Term
| When blood is returning from the lungs what is its pathway? |
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Definition
| it flows from pulmonary veins-->left atrium--> left ventricle--> body via the aorta |
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Term
| When blood is returning from the body what is its pathway? |
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Definition
| vena cavas-->right atrium --> right ventricle --> back to lungs |
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Term
| Why do birds have a better respiratory system than mammals? |
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Definition
| mammals don't have a flow through system, and always retain 20-35% of air |
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Term
| what is the pattern of air flow? |
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Definition
| trachea --> two bronchi --> bronchioles --> alveoli where gas exchange occurs |
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Term
| How does inhalation occur in mammals? |
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Definition
| when the ribs are pulled upward and the diaphragm flattens, the volume of the chest cavity is increased |
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Term
| how does exhalation occur in mammals? |
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Definition
| muscles relax, ribs and diaphragm return to their regulation position = chest volume declines |
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Term
| in mammals what controls most integrative functions? |
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Definition
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Term
| where are touch receptors located? |
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Definition
| the base of hair follicles |
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Term
| mammals have poorer _____ than reptiles or birds. |
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Definition
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Term
| Why do scientists believe that early mammals were nocturnal? |
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Definition
| because rods are more abundant than cones in most species |
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