Highest_priority_cards_11_-_all_duplicates

Question 1

Q: Key developments in the ancestors of birds leading to modern birds

Answer 1

> 200 MYA, after major extinction event, dinosaurs began rapidly diversifying in body size to fill new ecological niches
Over 50 M year period, theropod ancestors of birds continuously shrank
Small size, light weight allowed escape from predators by climbing trees, gliding, flying
66 MYA, K-T mass extinction, end of Cretaceous– their small size, efficient insulation (feathers), and ability to fly may have helped birds survive the dinosaur extinction event.
Underwent explosive adaptive radiation, forming the diverse group of birds that we see today.

Question 2

Q: How are birds related to dinosaurs?

Answer 2

Birds are closest living relatives to all extinct dinosaurs
Birds evolved from theropods, a group of meat-eating dinosaurs
Archaeopteryx may be the evolutionary link between dinosaurs and birds

Question 3

Q: Physical/behavioral similarities between birds and theropods?

Answer 3

Walking on two legs, scales on legs, pneumatized (air-filled) bones, having feathers, laying eggs, nesting and brooding.

Question 4

Q: Primary function of early dinosaur feathers

Answer 4

Insulation

Question 5

Q: What species is commonly considered the first bird?

Answer 5

Archaeopteryx
Discovery of this feathered fossil provided evidence that birds are flying dinosaurs and diverged from small, bipedal theropods.

Question 6

Q: Theropods

Answer 6

Two-legged, carnivorous dinosaurs
Include Tyrannosaurus rex, velociraptors
Ancestors of birds

Question 7

Q: Bipedal

Answer 7

Form of terrestrial locomotion where an organism moves by means of its two rear limbs or legs.

Question 8

Q: Where are birds classified taxonomically?

Answer 8

Birds are one of the five (actually >5 because multiple fish classes) classes in the Vertebrata subphylum.
Kingdom: Animalia; Phylum: Chordata; Subphylum: Vertebrata; Class: Aves.

Question 9

Q: What has driven many of the major characteristics of birds?

Answer 9

Adaptation to flight

Question 10

Q: Bird adaptations to flight

Answer 10

Reduced weight (pneumatized bones, lack of teeth)
Strengthened skeleton with several specific adaptations (details on separate card)
Strong flight muscles, attached to keeled sternum
Fast metabolism (can’t store heavy foods for long periods of time; also need energy for flight)
Large eyes (avoiding collisions in flight, spotting prey from a distance)
Efficient, one-way respiration system (details on separate card)
Missing/reduced organs decrease weight (e.g., no bladder, urethra, only one ovary in some birds; reproductive organs reduce in size outside of breeding season)

Question 11

Q: Bird skeleton adaptations to flight

Answer 11

-reduced in weight and strengthened (pneumatized bones)
-bones are reduced in number
-some bones are fused to increase skeletal strength
-keeled sternum (breastbone); attachment point for powerful flight muscles
-The “wishbone” (furcula)
–found only in birds
–strengthens thoracic skeleton to withstand the rigors of flight
–provides flexible attachment site for the breast muscles
-ribs have boney extensions that go from rib to rib
–serve as attachment sites for scapula muscles
–strengthen the rib cage overlapping with the rib behind them
–increase effectiveness of muscles involved in inspiration (yes, birds are inspiring, but this refers to intake of breath)

Question 12

Q: Name some examples of birds that cannot fly

Answer 12

Penguins
Ratites (ostrich, cassowary, emu, rhea, kiwi).

Question 13

Q: Bird characteristics

Answer 13

Feathers (defining characteristic)
Hard-shelled, amniotic eggs
Scales on legs
Beaks or bills
Tails
Wings (though not all can fly)
Relatively large eyes
Bipedal
Endothermic
Vertebrates
Pneumatized bones (except penguins, loons, and puffins)

Question 14

Q: Endothermic

Answer 14

Dependent on or capable of the internal generation of heat. The animal is able to maintain a relatively constant internal temperature, irrespective of the temperature of the surroundings.

Question 15

Q: Do any living animals have feathers besides birds?

Answer 15

No

Question 16

Q: Functions of feathers

Answer 16

Thermoregulation (more efficient than fur), flight, waterproofing, protection from the elements, camouflage, mating displays, aid in egg incubation

Question 17

Q: Common ancestor of modern reptiles, birds, and mammals

Answer 17

A scaled reptile
Over 300 MYA

Question 18

Q: Benefits of birds having relatively large eyes?

Answer 18

avoiding collisions in flight
spotting/capturing fast-moving or camouflaged prey

Question 19

Q: Key difference between bird eggs and reptile eggs

Answer 19

Bird eggs have a hard shell. Stronger and can support the embryo inside through harsher conditions (i.e. like rolling out of a nest).

Question 20

Q: Endothermic vs. ectothermic animal food consumption

Answer 20

To sustain their higher metabolism, endothermic animals typically require several times as much food as ectothermic animals.

Question 21

Q: Pneumatized bones

Answer 21

Air pockets within the bones
Reduced weight
Have criss-crossing struts or trusses for structural strength

Question 22

Q: Compare bones of flighted and flightless birds

Answer 22

Birds that have lost their ability to fly have heavier bones than flighted birds but they are still comparatively lighter than a similar sized mammal bone.
Ostriches and emus need the heavier bones to meet the demands of running.
Penguins need heavier bones to dive for food otherwise they would bob like corks near the surface.
Many flightless birds lack keeled sternum.

Question 23

Q: Name some parts of a bird that can tell us about their lifestyle

Answer 23

Beak, feet, wings (details on separate cards)

Question 24

Q: Modern bird feet, and reasons for the different adaptations

Answer 24

Foot type can indicate lifestyle
Two to four toes on each foot
Most perching birds and raptors have anisodactyl foot- three forward toes and hallux in back (homologous to human big toe). “Anisos” means unequal.
Some perching birds have zygodactyl foot- two toes forward and two rear facing. Good for clinging to and climbing through trees. “Zygo” prefix originates from “yoke,” and as a prefix, means “paired” or “union”.
Runners like the ostrich have a reduction in the number of toes and all their toes facing forward. Ostrich is only bird w/2 toes. Cassowary, rhea, and emu all have 3.
Webbed feet (useful for swimming and sure footing on wet ground):
-palmate: front 3 digits are webbed. Most common type of webbed foot. Ducks, geese, swans, gulls, and other aquatic birds.
-totipalmate: all four toes united by web. Pelican, cormorant, boobies, gannets.
Birds’ legs and feet are covered in scales, a holdover from their reptile ancestors.
Raptors (birds of prey) have long, strong digits w/ heavy claws for catching, holding, and killing prey. Owls, hawks, eagles, and falcons.

Question 25

Q: Two most common types of feet in perching birds

Answer 25

Anisodactyl- having the hallux behind and the other three toes are in front as in a thrush. “Anisos” means unequal.
Zygodactyl- having the toes of each foot arranged in pairs, with two toes in front and two behind as in a woodpecker, parrot, osprey. “Zygo” prefix originates from “yoke,” and as a prefix, means “paired” or “union”.

Question 26

Q: Words for two of the types of webbed feet

Answer 26

Palmate- front toes are united as in ducks and gulls.
Totipalmate- fully webbed; all four toes are united by ample webs, as in a pelican or cormorant.

Question 27

Q: Altricial

Answer 27

Helpless at birth or hatching and requiring parental care for a period of time.

Question 28

Q: Precocial

Answer 28

Young that are relatively mature and mobile from the moment of birth or hatching.

Question 29

Q: *Bird digestion adaptations

Answer 29

Gizzard
-birds lack teeth (save weight for flight), need extra grinding mechanism in their digestive system
-thick-walled, muscular pouch, often filled with swallowed sand or pebbles to help break down tough material
-captures bones in many carnivorous birds, which are regurgitated (e.g., owl pellets)
-allows them to consume food that is harder to digest such as insects, seeds, other plant material
-is the second chamber of two-chambered stomach (first chamber has gastric juices to soften food)
Crop
-expanded pocket off esophagus of some birds that bulges visibly against the bird’s neck when full
-adaptation for taking food in in large quantities quickly; helps avoid staying in one place too long to avoid predation
-pigeons, flamingos, and some penguins have evolved “crop milk”, a secretion from the crop, to feed their young
-crops also moisten and soften food. Seed eaters usually have larger crops, which help soften the seed before passing through the digestive track.
Waste excretion with reduced water content; also combines liquid and solid
-uric acid, the nitrogenous waste product of birds, requires less water than the excretion of urine by mammals
-eliminates 2x more nitrogenous waste than urea
-no bladder, no urethra
-weight reduction

Question 30

Q: One way a bird benefits from its lack of teeth?

Answer 30

weight reduction

Question 31

Q: Bird respiratory adaptations

Answer 31

Need efficient extraction of oxygen for breathing at high altitudes and for powering flight
-Large, 4-chambered heart pumps at a relatively high rate
-One-way airflow respiration, where air goes through lungs in one direction, aided by system of nine air sacs which act by negative pressure to move air through the lungs. Inspired air -> posterior air sacs -> lungs -> anterior air sacs. Takes two cycles of breathing in+out to get air through system.
-Highly efficient
-Lungs fairly small

Question 32

Q: Name one bird adaptation for avoiding heat loss while standing in cold water.

Answer 32

Countercurrent heat exchange- arrangement of blood vessels (arteries adjacent to veins) that allows peripheral cooling particularly of appendages and at the same time maintains an adequate blood supply without excessive heat loss. Arteries and veins exchange their heat content without mixing. Heat that would have otherwise exited the body is carried back toward core.
E.g., penguins, flamingos, ducks.

Question 33

Q: Besides bird legs/feet, where else does countercurrent heat exchange occur?

Answer 33

In nasal turbinates. Turbinates warm/moisten the air going into lungs and captures heat/moisture of exiting air. Warm air carries more water; turbinates cool it as it exists and reduce water loss.

Question 34

Q: What is migration? What is the benefit?

Answer 34

A regular seasonal movement made in response to changes in food availability, habitat, or weather.
Typically made in the fall following either the start of cold temperatures (moving toward warmer areas) or the start of dry season.
Takes advantage of the abundant food supply during the summer months.
Allows birds to avoid climatic extremes.
Increases the amount of space available for breeding and reduces aggressive territorial behavior.

Question 35

Q: What might trigger migration in an animal?

Answer 35

Hormonal changes, change in day length[, changes in food supplies, changes in temperature].
In birds, coincides with an accumulation of a layer of fat.

Question 36

Q: Ratite characteristics and adaptations, particularly those that distinguish them from flighted birds.

Answer 36

Flat, NOT keeled, sternum.
Wings tend to be small or rudimentary.
Developed adaptations for running.
-Relatively strong legs.
-Tend to have reduced number of toes; ostriches are only bird with two toes; cassowary, rhea, and emu have three; kiwi has four.
Feathers not adapted to flight.
-Not grouped in tracts. Evenly distributed.
-Lack barbs and have no feather vanes, which means they do not have to oil them, hence no preen gland.
-For thermal regulation and display, not flight, so weight is not an issue.
Thicker egg shells (withstand weight of heavier parent, also more protective since not high up in nest).
Young are precocial and can run or walk soon thereafter.
Most have communal nests, share incubating duties. Ostriches are the only ratites where the female incubates (share duties, with male incubating at night).

Question 37

Q: Compare penguin adaptations to other birds

Answer 37

-Most flightless birds lack the keeled sternum, but penguins have a keeled sternum and use strong chest muscles for swimming (“flying” through water)
-Penguin feathers are not arranged in tracts, more evenly distributed (as are many flightless birds). Why? Need densely packed feathers to stay warm in extreme conditions. Also don’t need to be light enough to fly.
-Feathers are short, stiff, and symmetrical. Comprised of an outer vane region and a ‘downy’ inner ‘after-feather’.
-Feather shafts are flattened to enable the close packing. The shafts of flighted birds are rounded. (Magellanic penguins have 70 per sq. in.)
-Land based flightless birds need heavier bones to meet demands of running. Penguins have heavier bones (though not as dense as mammals) to dive for food (rather than floating on surface).

Question 38

Q: Threats to birds

Answer 38

Pesticides and poisons
-Kill directly and indirectly.
-DDT kills directly by poisoning their nervous systems. Also reduces reproductive success by causing thin eggshells and reducing hormone levels necessary for egg laying. Toxins accumulate up food chain, so raptors are particularly susceptible.
-Ranchers have left poisoned animal carcasses out for wolves, which also killed eagles and other bird scavengers.
Global warming
-Long-distance migrants are particularly susceptible. Depend on precisely timed, once-a-year blooms of food to fuel breeding. Warming can change timing of food availability.
Habitat degradation
Pet trade (e.g., Bali Mynah, critically endangered)
Use of ornamental feathers (less common now)

Question 39

Q: Actions to help birds

Answer 39

Educating the public on the effect of poisons and pesticides.
Reduction of greenhouse gas emissions.
Help birds in your yard: clean your bird feeders and baths; install nesting boxes; add insect-friendly native plants; remove invasive plants; eliminate use of insecticides.
In northeast India and Borneo, Indian hornbill feathers are used in traditional ceremonies. Many zoos, including the SF Zoo, collect molted hornbill feathers and send them to these native lands.

Question 40

Q: Indicator species

Answer 40

An organism whose presence, absence, or abundance reflects a specific environmental condition. Indicator species are used to monitor the health of an ecosystem.

Question 41

Q: Examples of birds with altricial and precocial young?

Answer 41

Altricial: songbirds, raptors, parrots
Precocial: waterfowl & gamebirds such as turkeys, pheasants, guinea fowl. Also ratites.