Mammals and Flight Flashcards
What are the similarities between Dimetrodon and homosapiens?
Both have a single opening in the skull behind the orbit.
Differentiated teeth.
Evolution of jaw bones to become the malleus, incus and stapes.
Development of secondary palate.
Evolution of glandular skin and hair.
What was lactations original function thought to have been and what is its function now?
To keep eggs moist but now lactation is provide young with nutrition.
Where is milk secreted from?
Specialised mammary glands.
What period was lactation evolved in?
Jurassic period.
How do monotremes have young?
Lay eggs
How do monotremes feed their young?
Milk is secreted from pores in the abdomen and is licked from fur by young.
What is the body temperature of a monotreme?
32 degrees celcius.
How many monotreme species are there and where are they found?
Five extant species found in Australia and New guinea.
Describe the features of a duck billed platypus.
Electro sensitive beak.
Grinding pads to crush food.
Poison spur on ankle.
Paddle like tail.
How do Marsupials have young and how do they raise them?
Vivipary birth (live birth)
Young are born very young like an embryo.
Short gestation time due to yolk like placenta in mother and they’re reared in pouches.
Where are Marsupials found?
Australia and Americas.
How many species of Marsupial are found in S. America and in Australia?
S. America - 100 spp
Australia - 230 spp.
Why are young from placental mammals more developed at birth?
Development is allowed by direct feeding through mothers placenta.
What does the placenta provide?
Nutrition, waste disposal, antibodies and produces hormones.
How many species of placental mammals are there and when did most of them come about?
More than 5,300 species in 20 orders. Most major groups are diverged within a short time period during an explosive adaptive radiation.
