lecture 8 Flashcards
what anatomical (2) and behavioral (1)characteristics of crocodilians demonstrate their relatively close relationship to birds?
- 4 chambered heart
- oneway air flow through the lungs
- maternal care of offspring
what specific adaptations allow birds to fly? 5 main things ( things under them)
- lightweight skeleton
- hollow limb bones
- fewer individual bones - skeleton structure
- flight bones large flight muscles attach to a keeled sternum - Feathers
- sturdy and light
- flight: on wings, provide lift
- streamline the surface of the body
- insulate - reduced weight
- absence of teeth
- absence of urinary bladder
- 1 single ovary- matured egg laid as soon as it has a shell - metabolic adaptations (flying=energetically expensive)
-high metabolic rate provides energy for flight muscles (high Tb-39 to42 degrees celcius)
- efficient consumption &distribution of O2 :
#4 chambered heart
#one way flow through system- oxygenated and deoxygenated blood dont mix
How do the structures in bird’s bill , wings, and feet reflect its dietary and habitat specializations? (using examples)
Examples: bills
- hummingbirds that drink nectar=long, thin bills
- parrots eat hard nuts=stout, sharp bills
wings and feet are adapted to birds’ flying habits and habitats :
e. g. ducks have webbed feet that allow them to in water.
e. g. albatrosses have long, thin wings for flying long distances
during the Mesozoic era, why were the most mammals active only at night?
to avoid competition with and predation by dinosaurs, most which were active during the day
on what basis are the 3 major groups of living mammals distinguished?
On the basis of their reproductive habits.
- Monotremes lay eggs
- marsupials give birth to relatively undeveloped young after a short period of gestation
- placentals give birth to move developed young after a long period of gestatio
what 3 key adaptations in mammals allowed them to be active under many environmental conditions
insulating fur and fat and a high metabolic rate that generates lots of body heat
3 characteristics of living archosaurs: crocodilians and birds
- 4-chambered heart
- one-way airflow through the lungs
- strong maternal behaviour
crocodilians include 2 species
crocodiles and alligators
archosaurs include 2 living groups
aves and crocodilia
the aves descended from…(recent descendant)
dinosaurs
3 things the aves have in common with the dinosaurs they decended from
- skeletal structure
- scales on legs and feet
- walking posture
3 things the aves have that is different from the dinosaurs they decended from
- keratinized bill & no teeth
2. feathers and wings
earliest bird known
archaeopteryx
archaeopteryx still dinosaur like 4 characters
- claws on forelimbs
- teeth
- many bones in wings and vertebral column
- poorly developed sternum
archaeopteryx bird like character
feathers and wings (used winds to catch food)
structure of what 3 things indicates a bird’s diet (other habits)
- bill
- feet
- wings (e.g.penguin wings are specialised for swimming and inappropriate for flight)
flightless birds have 2 things
- small wings
2. small flight muscles
birds that are bipedal runners have
strong, muscular legs e.g. ostrich
4 key adaptations of mammals
- high metabolic rate and temperatures
- specializations of teeth and jaws
- parental care
- complex brains-cerebral cortex
- high metabolic rate and temperatures of mammals adaptations include (3)
- 4 chambered heart and complex circulatory systems deliver oxygen
- diaphragm
- fur and insulating fat
- specializations of teeth and jaws of mammals adaptations include
allow mammals to feed efficiently (CAN CHEW) - mammals have 4 types of teeth
- incisors
- canines
- premolars
- molars
- parental care of mammals adaptations include (2)
- uterus and placenta
2. mammary glands
- complex brains of mammals adaptations include (2)
cerebral cortext, part of the forebrain responsible for info processing and learning
- strongly influences behaviours
- associated with sense of smell
2 main groups of modern mammals
- prototheria (monotremes)
2. theria (live bearing)
2 types of theria (live bearing)
- metatheria (marsupials)
2. eutheria (placentals)
2 differences of marsupials and placentals
Marsupials :
- short pregnancy (<2 weeks)
- complete embryonic development in mother’s abdominal pouch (marsupium)
Placentals
- longer pregnancy (3 weeks- 2years)
- complete embryonic development in mother’s uterus -nourished through placental
