Final Test Part 2 Flashcards
(15 cards)
What was the original idea for why mammals found were they are
Mammals have disphered to practically all parts of the world from the tropics to the polar regions.
For a long time historical pattens of where mammals were found were explained by vicariance events -
refer to, where a once widespread species becomes restricted or split into isolated geographic locations through either the appearance or disappearance of some geological structure or barrier
Ex. Grand cayon - 2 squirrels north rim and south rim
geographically isolated → new species
Ex.) Study Cloverleaf intersection - meadow vole in each quadarant created different species because they couldn’t cross roads and became isolated
Where did marsupials evolve and how did they get to Australia
Marsupials - evolved in South America they got to Australia because it was connected via Antarctica but Antarctica was much higher at that point intime, Antarctica decided it wanted to go for the polar plunge and it went south
Everybody died on Antarctia, leaving marsupials now in South America and North America. Later on there was another vicariance event where the Panamanian land bridge occurred and all of a sudden, you had mixing of North and South American fauna and Marsupals declined in S. America.
But Marsupials in Australia managed to stay in isolation for a long time and so they did pretty well there and became dominant in Australia
What are the 2 most basic elements that explain everything we see today and how did we figure this out
•Time
Before Darwin and Wallace most naturalist believed that a species was found in an area because it was specifically designed to be there or created by god to be in that place
Bishop usher went back and found out that the world was 4000 years old and started on a Tuesday
Charles Lyell thought the world was older than 4000 years old
Biologist would find fossils and seashells in layers in the earth which conflicts with the idea that the would is only 4000 years old
Now we believe the world is approximately 4.5 billion years old
•Position of land masses
The ideas that continents moved was not accepted until more recently after the discovery of the tectonic plates
Continental drift was proposed by Wegener in 1929
Early on the default answer/explanation was a land bridge
At one point in time all of the land masses where together as a single land mass called Pangaea which then split into 2 land masses Gondwanaland and Laurasia
Chart the theory of island biogeography, find the equilibrium points and explain the charts
Theory of island biogeography - main variables are size and distance from mainland and time (but only for a short period of time)
Proximity increase chance they run into the island - wider angle - effects immigration more
Size has greater amount of resources - effects extinction more
The near large has the most and far small has the least
MacArthur and Wilson 1967 - tested on islands off the coast of Florida with different sizes and distances from Florida by killing everything and surveying bugs and found this to be supported
Why are there 25 orders of mammals while other groups like reptiles have less (5)
The time and position of land masses when these groups exploded and were evolving rapidly. When mammals first evolved they were fairly insignificant while reptiles exploded and were the dominating group 190 million years ago. At that time the contients were one as Pangaea which meant that they evolved as one ecosystem that produced 5 different orders (from trophic groups). Continental drift occurs and when the meteor hit and killed off the dinosaurs there were approximately 6 different continent which created convergent evolutions as they were isolated from each other and are not related in those 6 continents. 6 times 5 is 30 which is close to the 25 orders of mammals we see today.
What are the 6 continental faunal regions and describe the differences in there make up
- Ethiopian region - covers Africa south of Atlas mountains and the
southwest corner of Arabia, including Madagascar
•very diverse fauna
•52 families - 35% of all mammalian families
•20 of those families are endemic
•Includes animals like golden moles, aardvarks, hippos, and giraffes - Oriental region includes India, Indochina, southern China, and Malaysia,
and continental islands of Sumatra, Ceylon, Java, Borneo and the
Phillipines
•Wallace’s line separates oriental from Australian faunal regions
•50 different families
•5 endemic - tree shrews, culuogos, gibbons, tarsiers , hognosed bats - Palearctic region – all of Europe and Asia north of the Ethiopian and
Oriental faunal regions
•Despite its large land masses
•42 different families
•No endemic species 1 debated blind mole rats
•One of the reasons this faunal regions has such low numbers of endemics is because of the great interchange it had with other regions (Oriental, Ethiopian, Bering land bridge ) - Nearctic region – North America north of the tropics
•37 families - 4 introduced - Myocastoridae, Equidae, Suidae, Muridae, (Herpestidae)
•2 endemic - Antilocapridae, Aplodontidae
•Camels are believed to have evolved in N.A. And are no longer there - Neotropical region – includes Central and South America
•50 families
•19 endemic to South America
•One of the reasons that it has such a diverse faunal group is marsupials evolved in South America and it also has a lot of Eutherians. Myrmecophagidae, caviidae, bradypodidae
• There is a greate deal of interchange between the nearctic and Neotropics with approximately 30 families in common - Australian region includes Australia, New Guinea and Tasmania, but not
New Zealand and the islands of the Pacific
•28 families
•20 endemics - highest percentage
Besides the major zoogeographic zones are several islands that are often considered separately - e.g. Hawaiian, Aleutian and Galápagos Islands explain mammal fauna found in these regions and the descrive the different types of islands
Besides the major zoogeographic zones are several islands that are often
considered separately - e.g. Hawaiian, Aleutian and Galapagos Islands
1. Mammalian fauna on islands depends to a great extent on the Island (1)
size, (2) distance from mainland, and (3) age.
a. Theory of Island Biogeography
- Two types of islands (although arbitrary, just as is the distinction between
islands and continents)
a. Continental – detached fragments of continents, consisting of
continental rocks – such as British Isles, Ireland, Borneo and
Falkland Islands, and Madagascar
b. Oceanic – originating from volcanic rock and coral, such as
Hawaii, Galapagos and Aleutians
c. a third group of islands are called “fringing archipelagos,” such
as Philippines, West Indies, etc.
– lie close to continents and receive fringes of these faunas
How did mammals get to the various areas that now make up their geographic distribution?
Active dispersal - an animal is getting to a new location under its own power
Ex) Bats and whates have high potential of active disphersal
Passive dispersal - getting to a new location but not under their own power
•Accidently
•rafting - rain creates flood and animals get washed into water animal floats on log through bodies of water to new land
→ Some animals have pre adaptions which increase chances for rafting occuring example rodents have high salt tolerance’s which means they can drink ocean water
Active disphersal
• Corridor - 2 chunks of habitats and some suitable habitats between them that allows for or promotes movement between the 2 faunal regions that share alot ot similar species almost always have some kind of corridor
between them. The opposite of vicariance events
Sweepstakes Route - chance of making a dispersal is based on luck
Madagascar - Mozambique channel
Filter Route - Allows some species to pass but stops others from passing
(Reptiles vs amphibians through desserts)
Plays a huge role in what we see in the world
2 major filter routes:
• Bering land bridge
• Panamanian land bridge - led to the great faunal interchange between North and South America.
• 2 groups were able to pass from south America crossed to North America
while many North American crossed. Eutherians already went through one exchange with Bering land bridge with Asia and the best survived
Explain the superior competitiveness of Eutherians vs Metatherians
Metatherians
No flying or marine - limited by development more conservative body plan - start small and crawl to pouch
• Not able to exploit large sizes - largest is kangroo
• Never develop social behavior lack corpus callosum - neural band connects hemispheres
of brain to allow complex though, social structures
• 6% of all mammal - less diversity
( Dynamic Alternative )
• Genetics - low diplod numbers compared to Eutherians (rough correlation)
• Neural tissue develops best in a warm oxygen rich environment and short gestation periods don’t promote building a strong brain
•The extent of gestation allows for Eutherians to have more endothermic young to exploit more
challenging environments when it comes to temperature
• N.A is larger than S.A. (less of a factor )
Where did land fauna comefrom?
Fossil records - challanges w/ highly mobile groups
Certian mammals exhibit wide ranges of diversity because of high adaptability.
• Alot of circumpolar species - Arctic fox, wolf, weasels, caribou, moose
• Some families worldwide disription - canidae, vespertilleonidae or either highly mobile or we assisted
• Some times no reason
Deer mouse - all of U.S.
Florida beech mouse - 3 beechs on gulf-of Florida
Perissodactyla
Mesaxonic
“Odd toed ungulates ”
Mesaxonic - weight borne on the central digits with the main axis of the foot passing through the 3rd digit, which is the longest on all feet
Artiodactyla
Paraxonic
Even-toed unglulates
Paraxonic - weight borne on main axis of the foot passing through 3rd and 4th digits on all feet
2nd and 5th digits are sometimes present as “dew claws”
3 recent families of Perissodacyla - 6 genera and only 18 living species
- Equidae
- Tapiridae
- Rhinocerotidae - only one with head ornamentation (“ not true horn”)
Hind gut fermenters not as efficient, high crowned teeth
Mammals with head ornamentation
4 Artiodactyla
• Giraffidae
•Antilocapridae
•Cervidae
• Bovidae - only one with “true horn”
1 Perissodactyla
•Rhinocerotidae
Artiodactyla suborders - skull and stomach structure
10 families, 89 genera, 240 species
Suborders
•Suiformes (pigs) - 2-3 chambered; nonruminant
•Tylopoda (Camels) - 3 chamber, ruminating
•Ruminantia - 4 chambers; ruminating
