Module 15 Flashcards
when did the earliest fliers exist
Silurian
what was the earliest flyers?
ex
plants
evidence Cooksonia plant spores date back Silurian 433ma
what/when where the first insects on land/flying?
Late Silurian, small mites or Juvenile forms first insects hat crawled around the low water hugging terrestrial ecosystems of the Silurian and Early Devonian
what was the first powered flight
insect
origin hazy, insects in the Carboniferous already adapted to life in skies
Meganeura
giant dragonfly
300Ma end Carboniferous
1.What body part evolved into wings to allow flight?
2.What did having wings do in terms of the dragonflies ability to hunt?
3.What has allowed the animals (including Meganeura) from this time period to grow so big?
4.What allows animals to lay their eggs on land so that they are no longer tied to the water?
5.What large group of animals evolved on land as a result of this new ‘egg out of the water’ adaptation?
what is an excite?
in water: early arthropods had excite that joined limbs
used for filtering water/gill
plate like structure also used for locomotion
insects may have them at larval nymp stage but adults often become wings
what is the most primitive flying insects
why
how did exite change into wings
mayflies
-can’t fold wings
-nymph stage is aquatic with well developed exite plates that can be flapped to increase water movement, reparation, locomotion
- already have developed muscles for flapping
Is their much diff b/w swimming and flying for insects
not really cuz their small
first ex of airborne vertebrae?
when did it live
name
size
fancy feature
Late Permian
- reptile called Coelurosauravus (“hollow lizard grandfather”)
- 40cm lived in tropical shores now Germany, Uk, Madagascar
- 20 long curving bones 90 degrees to body jointed at base. has 30cm skin membrane
- “wing” can be folded across body
similar animals to Coelurosauravus
- Triassic, Sharovipteryx which had a membrane that stretched between its hind legs in a delta shape and a smaller skin membrane attached to the front limbs, a bit like a paper airplane.
-Draco (now), a gliding reptile from SE Asia (see video below). Draco is an insectivore, probably Coelurosauravus was as well. In addition to flying, Draco uses its aerofoil (wing like structure) for display purposes and also for thermoregulation, the skin on the wings allowing this cold blooded creature to warm up more rapidly.
Draco
1.How far can the lizard glide?
2.How do the wing like structures work?
First fully powered flight?
- name
- when
- successful?
pterisaurs “winged lizards”
-evolved 228ma in late Tri
- had air spaces in bones
-successful common in skies till 65ma end Cre mass extinction
diff b/w bat and pterosaur wings
bats” use digits to support wing
pterosaur: support wing membrane along one slender finger (digit 4)
- next 3 digits normal size and ended in claws
- wing stretched long digit IV, the sides of the body, and in many groups the hind limbs too
how did pterosaurs feed
- lots fossils found in shallow marine sediments with lots associated with fish
- prob ate fish
- prob some fed like skimmers (like petrels today)
- some dived such that head/neck only part underwater (wings too delicate to go underwater)
did pterosaurs filter feed? scavenge?
examples
-some filter fed
(ex Pterodaustro probably used the bristle structures on its jaw to strain micro-organisms and algae out of the water. The food was probably mashed on teeth present in its upper jaw)
- Quetzalcoatlus, another pterosaur from the Late Cretaceous, was a scavenger, feeding on the carcasses of dinosaurs, although another hypothesis is that they were terrestrial stalkers who fed on small vertebrates either on land or in stream beds.
how big did pterosaurs get?
how was their brain size?
Some got big. Quetzalcoatlus had a wingspan of about 10 – 11 m (33 – 36 ft)!
Relative to their body size pterosaurs had bigger brains than dinosaurs. Perhaps this was to accommodate the processing power required for flight.
1.What is the name of the ‘giant of the air’ discussed in this publication?
2.What was its wingspan?
3.How did it take off into the air?
4.Why does flight performance degrade as body size increases?
5.What was the main type of flight used by these animals?
did pterosaurs have fur?
what does that indicate?
covered in fine fur called pychnofibers
- maybe indicate could generate own heat
In one form called Sordes, the pynchnofibers were longer and more developed on the underside… perhaps as an adaptation to incubate eggs or insulate hatchlings?
1.Which pterosaurs are ‘the undisputed king of the skies’?
2.How long is the distance from wingtip to wingtip in this group?
3.Why are pterosaurs not agile on land?
4.What is the function of the head crest?
what are the 2 groups of pterosaurs
rhamphorhyncoids (have long tails that end in dimound shape vein) and the pterodactyloids (more advance, no tail)
did rhamphorhyncoids or pterodactyloids evolve first
rhamphorhyncoids evolved first in Tri
what was the size of large rhamphorhyncoids in Tri, when did most become extinct?
when did pterodactyloids evolve? sizes?
- large cow, end Jur
- Jur
- sparrow -> eagles size
- diversity very high till end Cre
oldest pterosaur found?
could it fly?
Eudimorphodon from the Late Triassic of Italy.
Eudimorphodon was a fully adapted and able flyer. We are lacking the transitional forms to shed light on the early evolution of this group
last common ancestor b/w pterosaurs and dinos? when?
archosaur back in the Triassic, a group of lizards who would give rise to the dinosaurs, crocodiles, pterosaurs and the birds
is their transitional forms b/w pterosaurs and dinos
not found
1.Where was this fossil found and what age it it?
2.What genus of pterosaur was this?
3.What did this reptile hunt?
4.What process caused the dinosaurs to shrink on the Island now found in Romania? What length were the biggest dinosaurs found on the Island?
5.What role did the giant pterosaur fill in the ecosystem?
6.What is the wing span of the giant pterosaur and how long was its skull?
7.What was different about its neck? and what was the function of this different structure?
8.What did this pterosaur prey on?
9.How was this reptile able to fly and what was its wing span?
10.What options would flying have opened up to this animal group?
how do birds breath?
inhalation, 75% of the air bypasses the lungs and goes into a posterior air sac, which connects with air spaces in the bones and fills them with air. The other 25% of the air goes directly into the lungs. As they exhale, the used air flows out of the lungs and the stored air from the posterior air sacs is forced into the lungs. As a result, bird’s lungs receive a constant supply of fresh air during both inhalation and exhalation.
what was found in the Solnhofen limestone,
what does the limstone consit of?
why is this lace good for fossils
Archaeopteryx
rock that was originally deposited as lime rich sediment on the edge of the Tethys Sea, along an archipelago in semi-arid sub-tropical conditions
fossils rare but spectacular
- Why does the Solenhofen limestone demonstrate such spectacular preservation? (choose one or more answers from the list below)
a)Creatures covered rapidly by sediment
b)High salinity
c)Low oxygen levels
d)High volumes of volcanic ash
e)Fine grained sediment preserves fine details
- What about the environment of deposition of the Solenhofen Limestone would cause high salinities/low oxygen?
a)Tropical climate
b)Lagoons restricted from main ocean
c)High evaporation rates
d)Restricted vertical circulation of water in lagoons
Archaeopteryx
earliest birds, Late Jur in Germany
- had bird like features: feathers and a supracoracoideus tendon notch
- had retile like features: teeth, a long bony tail and claws on the wings
transitional form
what is a common ancestor
a branching point FROM WHICH apes that would become chimpanzees AND apes that would become humans DIVERGE via numerous transitional forms. It is these transitional forms that show that evolution happens.
are Archaeopteryx the common ancestor of birds and theropod dinosaurs
no
(could prob classify as early bird)not direct ancestor
what did birds evolve from?
Birds probably evolved from another “avian-dinosaur’ in the group of theropod dinosaurs called the Maniraptora that includes dinosaurs like Deinonychus.
what is the supracoracoideus tendon notch?
a bird trait
pully sys of the supracoracoideus muscle that lies below the wing (maintains aerodynamic stability) but is attached to the upper side of the humerus, so it can raise the wings.
To get to the humerus it has to travel through a notch in the scapula. It is this notch (the supracoracoideus tendon notch) that is an indication of “bird-like” flapping
how does the down flab work?
Large breast muscle (pectoralis) attach to a keel of the sternum, and the humerus of the wing provide the downward thrust of flapping. These large muscles provide a low center of gravity and aerodynamic stability
was Archaeopteryx fully developed for flying?
no,
had a supracoracoideus tendon notch (so it could flap its wings), it did not have a large keel on the sternum on which large breast muscles could attach for the powerful flapping seen in modern birds
debate as to the position of Archaeopteryx in the story of the evolution of birds is still one that is raging and it is possible that the first birds arose from a different group of “avian-dinosaurs’.
1.Which group did the scientists believe were the ancestors to the birds?
2.What is the initial proposed use of feathers in the small theropods in which they first evolved?
3.Which digits were lost in the theropod lineage that eventually led to birds?
4.What feature evolved that eventually allowed birds wing joints to move to create thrust for flight?
5.What is one suggested function of feathers that may have directly affected the hatching success of dinosaur eggs?
6.According to this paper, when did the ancestor of all living birds exist?
3 hypothesis for the development of flight in the earliest birds
earliest: Arboreal Hypothesis
Cursorial (or ground up) Hypothesis
Wing Assisted Incline Running Hypothesis (WAIR)
what is the Arboreal Hypothesis
birds evolve from feathered, tree climbing theropod dinosaurs jumping from trees and either gliding to the ground or to another tree
like flying squirel
what is the Cursorial (or ground up) Hypothesis
ancestral theropod dinosaur that had feathers on its arms, possibly initially for insulation or display purposes, would leap in the air while trying to catch insects or other small mobile prey
what is the Wing Assisted Incline Running Hypothesis (WAIR)
flapping and eventually flight would develop as winged dinosaurs run up inclined surfaces (either chasing prey or being pursued by a predator). Flapping would help the animal get up the slope.
This is a technique seen in modern birds today.
In this scenario feathered arms become secondarily useful for adjusting body attitude midair or helping maintain balance when you land.
Diverse Cre birds
Confuciusornis was a bird about the size of a pigeon from the Early Cretaceous of China. It is starting to look a lot more like a modern bird, as it has lost its “dinosaur teeth” in its beak, but still has claws on its wings and a relatively small breast bone (keel). Over several hundred articulated specimens have been found leading to the question of whether it may have flown in flocks?
Enantiornithes are a diverse group of small birds ranging from sparrow to starling size. They are found in a range of different sediment types from marine to inland, suggesting they lived in range of habitats. Almost all members of this group retained teeth in their beaks and claws on their wings, but none of them had long bony tails.
Some even lost the ability to fly, for example Ichthyornis (fishing bird) that is found in sediments of the Western Interior Seaway. This very “seagull-like” bird still has teeth in its beak.
how did birds survive extinction?
eat seeds
1.How did the early modern birds with toothless beaks survive the extinction event at the end of the Cretaceous?
2.Would you expect the teeth from the bird-like dinosaurs to become more or less diverse over time if the ecosystem was gradually declining in the Late Cretaceous, prior to the impact event?
3.Explain your answer to Question 2.
4.What did the tooth data end up favoring with respect to diversity in the Late Cretaceous?
5.What did this suggest about the speed of the extinction event at the end of the Cretaceous?
1.What avian characteristics did Ichthyornis possess?
2.What unexpected morphological structures were present in Ichthyornis and Hesperornis?
3.What morphological characteristics did ornithurines all possess? What age are the members of this group?
4.Which niche did the ornithurines live in?
5.What is the use of the half-moon structure in the wrist of birds?
6.What is the difference between ‘Opposite Birds’ and Modern Birds?
7.What niche did ‘Opposite Birds’ live in? How do we know?
8.Why did early birds lose their teeth?
9.Why is it believed that beaks are advantageous?
10.What group gave rise to today’s birds?
11.Did birds with and without teeth coexist in the Cretaceous?
12.What main characteristics were most advantageous to survival at the end of the Cretaceous?
13.What are the characteristics shared by the last common ancestor of all birds?
14.How many lines of birds made it across the extinction to give rise to the 10, 000 species of birds on the planet today and which broad habitats do they occupy?
what is adaptive radiation
did birds show this?
Adaptive radiation is an evolutionary process where organisms rapidly diversify into new species
-environmental change can create new challenges for organisms, cause new resources to become available and make additional environmental niches available
occurring here at the end of the Cretaceous in the birds as a result of their abilities to dive, swim, or seek shelter in water and marshlands. Many species of avians can build burrows, or nest in tree holes or termite nests, all of which provided shelter from the environmental effects at the K/P boundary.
1.What is causing the sudden drop in diversity at the end of the Cretaceous?
2.How rapid was this event?
3.Which broad types of birds survived and which didn’t?
4.Which of the following (a - c) do you think is the primary reason for the adaptive radiation of birds at the end of the Cretaceous? a. New environmental challenges b. New resources available, c. New environmental niches available
5.Justify your selection in Question 4.
6.Why did the birds survive the event at the end of the Cretaceous? List some possible reasons.
