Biology Questions and Answers

(Greg DeLong) #1

Biology Questions and Answers


Mammals



  1. What are the typical
    features of mammals?


The typical features of mammals are:


body (more or less) covered with presence of the diaphragm muscle (thathair; (^)
separates the thorax from the
abdomen); mammary glaproduce milk (in females); ends thatnucleated (^)
blood red cells; middle ear with three
ossicles.



  1. What are the three main
    groups into which mammals
    are divided?


The three groups into which mammals


are divided are: monotremprototherian, e.g., platypus), marsues (or (^) pials
(or metathkangaroos) erian, fand placental (or eutherian,or example, (^)
such as humans).



  1. Do all mammals have a
    placenta?


Mammals of the monotreme group
(platypus, eclaying, and they do not have a placehidnas) are oviparous, enta.gg-
Mammals of the marsupial group


(kangaroos, koalas,have a placenta either; females of this opossums) do not (^)
group give birth to embryonic young
that then continue development within
the mother’s pouch. Placenta only forms
in female placental mammals.



  1. What are the main orders of
    placental mammals? What are
    some representative species
    and distinguishing features of
    each of those orders?


The orders into mammals are divided are the followinwhich placental (^) g:
Artiodactyls,number of fingers in claws or paws like, mammals with an even (^)
e.g., cows, sheep, giraffes. Carnivopredators with canine teeth like dogs,rous,
lions, tigers. Cetaceans, aquatic animals
without posterifishes, like whales anor limbs and dolphins.d similar to
Edentates,teeth, like creatursloths, armadillos,es with rare anteaters.or absent
Lagomorphs, small-sized mammals
having three pairs ogrowing incisive teeth specialized if continuously (^) n
gnawing, like rabbits and hares.
Perissodactyls,(hooved), big-siz also ked animalsnown as ungulates with an odd (^)
number of fingers in each paw, e.g.,
horses ancharacterizd rhinos. Primates,ed by the big crani (^) um and
well-developed brain, like humans and
apes. Prowhose nose and superior lip form theboscideans, big-sized animals
trunk (snout), e.g., elephants.
Chiropterans, flyin(bats). Rodents, animalsg nocturnal mammals with two pairs
of continuously growing incisive teeth,
e.g., mice, rats,Sirenians, aquatic mammals of castors, squirrels.
freshwater, like dugongs and manatees.deprived of posterior limbs,
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