Lecture 14- Deuterostomes II Flashcards
What is the name of the group of animals whose ancestor evolved jointed limbs?
Sarcopterygians
What animals are included in sarcopterygians?
Coelacanths, lungfishes and terapods
What proved that coelacanths are not extinct?
One was caught off of the coast of South Africa in 1938
What is the name of the species of coelacanth discovered in 1938?
Latimeria chalumnae
What is the name of the second species of coelacanth discovered in 1998 of an Indonesian island
Latimeria menadoensis
Why is a cartilaginous skeleton in the coelacanth clade derived?
Because their ancestors were bony.
Where do the remaining species of lungfish exist?
Swamps and muddy waters in South America, Africa and Australia
Where did lungfish derive their lungs from?
Lung-like sacs of their ancestors as well as gills
What happens to lungfish when their ponds dry up?
They can burrow deep into the mud and survive in an inactive state whilst breathing air
How did some early aquatic sarcopterygians evolve into ancestral tetrapods?
They began to use terrestrial food sources and became more adapted to life on land
Why are most amphibians confined to moist environments?
Because they lose water rapidly through their skin
Eggs are enclosed in delicate membranous envelopes that cannot prevent water loss
How are amphibian eggs laid in water usually fertilized?
Externally to their body
Where has a diverse mode of reproductive and parental care especially developed?
Tropical and subtropical areas
What are the 3 major groups of amphibians?
Caecilians, anurans, salamanders
What are ceacilians?
Worm like limbless tropical burrowing or aquatic amphibians
What are anurans?
Tailess frogs and toads
What adaptations do some anurans have to their skin?
Tough skins to live in dry deserts
What do all anurans have?
Very short vertebral columns which a strongly modified pelvic region for leaping, hopping or propelling forwards
Where are salamanders most diverse?
Temperate regions of the northern hemisphere, also found in cool moist mountains in Central America
On what do salamanders live?
Rotting logs or moist soil
What do amphibians use for gas exchange in addition to their lungs?
Skin and mouth lining- one species has lost their lungs
What name is given to retention of the juvenile state?
Paedomorphosis
What has paedomorphosis allowed in salamanders?
Evolution of a completely aquatic lifestyle several times
What type of fertilization do most species of salamanders have?
Internal- achieved through transfer of small jelly like capsule with sperm embedded in its surface
What name is given to the small jelly like capsule with sperm embedded in its surface used by salamanders for fertilization?
Spermatophore
What are some complex social behaviors of anurans?
Males utter loud species-specific calls to attract females and to defend breeding territory
What name is given to the way a few species of frogs, salamanders and caecilians give birth to well-developed young?
Viviparous
Why are amphibians the focus of much attention today?
Species are declining rapidly in mountainous regions of Western North America, south and central america and australia
Why are frog species declining?
Habitat alteration by humans, hole in ozone layer, pollution, pesticides and herbicides, pathogenic chytrid fungus
What name is given to animals that evolved water conserving traits?
Amniotes
What is an amniote egg?
A relatively impermeable to water egg which allows the embryo to develop in a contained aqueous environment
What does the leathery or brittle, calcium-impregnated shell allow and not allow?
Allows passage of gas
Does not allow evaporation of fluids inside
Where do amniote eggs store large quantities of food?
In the yolk
What else is found inside an amniotic egg?
Extraembryonic membranes
What do extraembryonic membranes do?
Protect the embryo from desiccation and assists in gas exchange and excretion of nitrogen waste
What did modifications of the amniote egg allow?
The embryo to grow inside and receive nutrition from the mother
What other adaptations made amniotes able to colonize dry land?
Tough impermeable skin reduced water loss
Kidneys allowed excretion of concentrated waste nitrogen
What two major groups did the amniotes split into during the carboniferous?
Mammals and reptiles
What name is given to the group of reptiles that has changed very little over the last intervening millenia since amniotes diverged?
Turtles
What is the body structure of turtles?
Dorsal (extension of ribs) and ventral bony plates form a shell
Where do most turtles live?
Aquatic environments,
tortioises and box turtles are terrestrial
What has human exploitation of sea turtles done?
Resulted in their decline, all species of sea turtle are now endangered
What do turtles eat?
Some are strict herbivores/carnivores
Most are omnivores
What is the second most species rich clade of living reptiles?
Lepidosaurs
What two groups make up the lepidosaurs?
Squamates (lizards, snakes etc.) tuatares
How are tuatares different from lizards?
Tooth attachment
Several internal and anatomical features
What is the skin of a lepidosaur like?
Covered with horny scales that reduce water loss but stop gas exchange
How do lepidosaurs carry out gas exchange?
Lungs by bellow-like movement of ribs
What is the heart of lepidosaurs like?
Divided into chambers that partially separate oxygenated and deoxygenated blood
What does the separation of lepidosaur blood inside their heart do?
Allows them generate high blood pressure and sustain high metabolism
What do lizards eat?
Insectivores, some are herbivores, some eat other vertebrates
What is the largest lizard?
predaceous Komodo dragon in the east indies
How many limbs do lizards walk on?
Most have 4
Limblessness has evolved several times in burrowing and grassland species
What is a major group of limbless squamates?
Snakes- all carnivores, some have venom glands
What is the remaining reptilian group (not turtles, lepidosaurs)
Archosaurs
When did the dinosaurs become extinct?
The Cretaceous-Tertiary boundary
What groups make up modern crocodilians?
Crocodiles, caimans, gharials and alligators
Where do crocodilians live?
Tropical and warm temperate climates
Where do crocodilians spend their time and built their nests?
In water
On land or floating piles of vegetation
What do crocodilians eat?
All are carnivorous
Eat vertebrates including large mammals
What did birds emerge from?
Theropods- a group of predatory dinosaurs
What features did theropods have?
Bipedal stance Hollow bones furcula (wishbone) Elongated metatarsals with 3 fingered feet Pelvis that points backwards
What two major groups do living bird species fall into?
Palaeognaths
Neognaths
What are paleaognaths?
Secondarily flightless and weakly flying birds
Name some paleaognaths.
South and central american tinamous, rhea,emu, kiwi, casowary, ostrich
What evidence shows that feathers are highly modified scales of small predatory dinosaurs?
Fossil dinosaurs discovered in Liaoning province in North eastern china
What is the oldest known avian fossil?
Archaepteryx
What did archaepteryx have?
Teeth and feathers, long wings, tail and furcula
What was the evolution of feathers a major force in?
Diversification
What do the large quills that support wing feathers arise from?
The skin of the forearms
What were the bones of theropods like?
Hollow with internal struts to increase strength
What did the sternum do in theropods?
Forms a large, vertical keel to which flight muscles are attached
What adaptation allows birds to control temperature?
Holding feathers close to or elevated from body
What adaptation allows birds to exchange gas?
Unidirectional flow of air
What happened to teeth prominent in dinosaurs in birds?
They were secondarily lost
What happened to mammals after the mass extinction of dinosaurs at the end of the mesozoic era?
Mammals increased in number and size
What does the difference in the number, type and arrangement of teeth in mammals reflect?
Their varied diet
What 4 key features distinguish mammals?
- Sweat glands
- Mammary glands
- Hair
- 4 chambered heart
What is the 4 chambered heart of mammals convergent with?
Archosaurs, including modern birds and crocodiles
In what mammals has hair been greatly replaced with insulating blubber?
Cetaceans (whales and dolphins)
What are the two major groups of mammals?
prototherians
therians
Where are the only three species of prototherians found?
Australia, New Guinea
What are the three species of prototherians?
Duck billed platypus
Two species of echidnas
How do prototherians differ from therians?
They lack a placenta, lay eggs and have sprawling legs
Do not have nipples of mammary glands, milk oozes out and is lapped off the fur by offspring
What are the two major groups of the therian clade?
Marsupials and eutherians
What do females of most marsupials have?
A ventral pouch to carry and feed offspring
What did marsupials radiate to eat?
They became herbivores, insectivores and carnivores, but none live in the ocean
What can some arboreal marsupials do?
Glide
What are eutherians?
More developed at birth, no external pouches to house young, they have placentas.
What is the largest group of eutherian?
Rodents
What defines rodents?
Unique morphology of their teeth
What are the next largest species of eutherians?
Bats, then moles and shrews
What behaviors by some eutherian groups helped to transform the terrestrial lineages?
Grazing and browsing favored evolution of spines, tough leaves and difficult to eat growths
What groups of species evolved as a result of social hunting behavior?
Canid, felid, primate lineages
Can small or large animals survive on food of lower quality?
larger- hence large sizes evolved in grazing and browsing animals
What ancestors did cetaceans evolve from?
Artiodactly ancestors
What was the common ancestor of primates?
A small, arboreal, insectivorous mammal
What traits distinguish primates from other mammals?
Opposable digits and grasping limbs
What are the two main clades of primates?
Prosimians and anthropoids
What animals make up prosimians?
Lemurs, lorises
Where do prosimians live?
Africa, madagascar and tropical asia
What species make up the anthropoids?
Tarsiers new world monkeys Old world monkeys Gibbons Orangutans African apes and humans
What are all new world monkeys?
Arboreal, many with long, prehensile tails
Where do old world monkeys live?
Many are arboreal
Some are terrestrial
When did the lineage split leading to hominid clade and chimpanzees occur?
6 million years ago
What were the earliest protohominids known as?
Ardipithecines
What did ardipithecines have?
Distinct morphological adaptation for bipedal locomotion
What is the advantage of bipedal locomotion?
Frees forelimbs to manipulate/carry objects
Elevates eyes to spot predators/prey
Energetically more economical
What group decended from ardipithecines?
Australopithecine
What two austalopithicines lives in eastern Africa 4-5 million years ago?
Paranthropus (2 different species) and A.afarensis
What group gave rise to the genus Homo?
A.afarensis
Which group gaverise to Homo habilis?
A.garhi
What two groups did Homo habilis give rise to?
H.erectus and H.ergaster which gave rise to H.sapiens
What happened to brain size and jaw size in the lineage leading to Homo Sapiens?
Brain size increased
jaw size decreased
What favored increasing brain size in H.sapiens and ancestors?
Increasingly complex social life to increase communication
What does the simultaneous change of brain and jaw size suggest?
That they are functionally correlated.
When did several Homo species exist?
During the mid-Pleistocene epoch
What were all of the Homo species that existed during the mid-Pleistocene epoch?
Skilled hunters of large mammals
Concept of life after death arose
When were species of Homo neanderthalensis widespread and where?
Europe
75,000 and 30,000 years ago
What name was given to the Homo Sapiens that overlapped briefly with the H.neandethalensis?
Cro-Magnons
they probably exterminated the H.neanderthalensis
How is human language different to other animal vocalizations?
Richer in symbolic character
How was food obtained in human societies?
Pastoralism (herding large animals)
Agriculture
