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Describe a typical 100,000 glacial year cycle
Cycle: Ice age –Warm Period-Ice Age
Determined by earth’s orbit
Earth's tilt is slowly decreasing today. As it does so, are the polar regions receiving more or less solar radiation in summer? In winter?
Less tilt-less seasons
More tilt- more seasons
More intense seasonal differences
How did tectonic plate movement lead to the isolation of Antarctica? What were the climatic consequences of the isolation of Antarctica?
South America separated from Antarctica creating global circulation around pole, creating COLD water- creating ice caps
.How did the Closure of Isthmus of Panama effect climate in the North America? Why?
Led to gulfstream going up to the North Pole and resulted in cooling
How did the opening and closing of gateways alter ocean circulation and change climate?
When planet has pathways of ocean circ around equator
If open, warm water circulates, warm planet
If closed, cold water current, cold planet (moisture and water to create ice)
.Over the last 40 millions, how would you characterize the temperature trends on earth?
Eocene until now
Cooling has taken place over the past 40 mil years,
led to changes in horses and whales
How does the Milankovitch theory explain the advance and retreat of glaciers?
The shape of the orbit path around the sun
The angle of tilt of Earth’s axis of rotation
Under what climatic conditions do glaciers advance? Hint - Summer and winter conditions.
Glaciers advance when more snow accumulates in winter than melts during cooler summers
Water and cooling needed
What are causes of the long term (millions of years) swings between hothouse and icehouse conditions?
What are the causes of large-scale glaciation, and the controls on ice advances and retreats within ice ages?
Have to have moisture and cold water
Result of the gulfstream in N America
What information is provided by oxygen isotope data
Tells us how much oxygen and C02 were in the atmosphere, can find evidence by looking at ice cores
What is Albedo
What is the evidence that Glaciers were widespread
U Shaped valleys, striations, IRDs
What is the Greenhouse effect?
What is the relationship between mountain building, weathering, and climate (Atm. CO2)?
When you have lots of mountain building (continental-continental collision) you get lots of ice and snow, creating a high albedo, lowers CO2
transitional whale; importance is its ankle bone, links whales to hoof animals
ancestor to modern whale, totally marine, have hip bones
Describe Ambulocetus. What is it importance?
involved in the terrestrial mammal to whale transition. nicknamed the walking whale. It was similar to alligator. It also swam with its tail up and down. Also, the torso and nose would lengthen even more. It lived primarily in the freshwater.
Describe Pakicetus. What is it importance?
One of the earliest whales
Teeth are similar to later whales like Basilosaurus
Describe some basic trends in horse evolution. Contrast the old "linear" view of horse
evolution with the more current "bushy" view.
Most of horse evolution is branching trees and not linear
Discuss evolution of whales from land dwelling animals to aquatic animal.
Reduction of hind limbs and lengthening of torso, change in forelimbs, change in hearing (jaws enable better hearing), and retraction of nostrils and telescoping of head;
also smaller eyes, nostrils on top of head.
Baleen whales evolved because of climate cooling and increase in upwelling thus making them more productive with krill and then don’t need teeth
Discuss the evolution of whale hearing. How do modern whales hear?
Modern whales hear through the assistance of the lower jaw bone and a dense bone called a bulla
Explain the rapid adaptive radiation of mammals at the beginning of the Paleogene.
Adaptive radiation – taking over their habitats (what drives evolution)
Mammals took over niches that were vacant, adapted
What were horses like in the warmer climate era
warm climate-ate leaves one by one in forest-know this from jaws and legs
Cool climate – grasses, food changed. Open grassland – horses jaw changed to be more like a lawnmower; teeth are longer and stronger to be able to grind the grass; legs became longer with a hoof so they could be able to run
Mammals dominate the Cenozoic. Did mammals out-compete the dinosaurs?
No. Mammals were better apt for the catastrophic conditions caused by the meteor strike that killed off the dinosaurs.
Name two suborders of Cetacea. Be able to identify the skulls of these whales.
Tooth whale – odonicedus (sp)? Has teeth, can echolocate
Baleen Whale- does not have teeth, has a filter feeder
Over time,groups of land-dwelling vertebrates returned to life in the sea, as air-breathing swimmers. Name one extinct, and one still living.
Extinct: Marine reptiles
What characteristics of modern whales point to a terrestrial origin?
What is echolocation? What whales can echolocate? Be able to identify the skulls of
Echolocate is received through jaw
Tooth whales are the only whales who echo locate
What is the closest Terrestrial relative of whales? What is the evidence for this
Most closely related to even-toed hoofed mammals, like camels or hippopotamuses
Evidence is in the ankle bones of Rodhocetus, an early whale
What morphologic features link whales to artiodactyls (hoofed animals)?
Rhodocetus – ankle bone
What was the effect of C4 grasses replacing C3 grasses?
Silica content became extremely high, only today’s horses were able to adapt and survive
describe the general characteristics of Australopithecines, when they lived, and their place in the evolution of humans?
Transition out of forests and trees b/c climate change during Miocene in African Rift Valley; slow maturity in children meant better learning;free hands for holding; bipedal; brain made them evolve; bigger pelvic canal
Compare the two lineages of Miocene Apes represented by Sivapithecus and Dryopithecus.
Sivapithecus: Ancestor to modern orangutan; powerful jaws and thick enameled teeth
Dryopithecus: evolved 13mya; modern apes, chimps, and humans; migrated into Europe and back into Africa; best known of all is Proconsul
Could Sahelanthropus tchadensis stand up right? What is the evidence? What is the importance of Sahelanthropus tchadensis?
Yes, foramen magnum at intermediate position; transitional fossil between chimps and hominids
Discuss those characteristics that mark the genus Homo. What makes our species a predominate force on Earth?
Increase cranial capacity,
disappearance of saggital crest
change in diet
increase reliance on tools
Allometry: body and brain = as brain increases, more energy is required. 2% body weight, accounts for 20% of energy to run
example of an extinct Sivapithecine that lived 300,000 years before present.
Extinct Sivapithecine: Gigantopithecus
Sivapithecids used to be considered as early hominids, but have more recently been considered more closely related to what living hominoid?
How did Oldowan and Acheulean tools and tool use differ?
Acheulean tools made by Homo erectus were more advanced, longer, and deadly
How does teeth size and diet affect human evolution?
Teeth size is associated with diet. Overtime through primate evolution, teeth size became smaller and had more variety as primates transitioned from herbivore diet to a more carnivorous diet.
What are the evidence and the importance of an upright stance in Hominids?
The evidence deals with the position of the foramen magnum in fossils. It is important for many reasons such as ability to travel long distances, better support for bigger cranial capacity, etc.
What are the primary differences between H. erectus and H. sapiens?
H erectus had a smaller pelvis and brain
however, H erectus were taller and had a femur built for running
What is Ardipithecus ramidus?
It is part of the lineage for evolution of humans
small brain size, have small canines;
List some of the new discoveries about Ardipithecus ramidus.
found on top of rift valley where it was a cooling environment with a more woodland like area. fossils suggests it was bipedal, erect walking;
hands and feet-->discover animal was able to climb trees like a chimp, also stood up right and walked
What is Australopithecus afarensis?
“Lucy” is a mixture of ape and human features
Profound brow ridge, Heavy teeth = more of a plant eating.
It shows that small brained hominoid (1/4 size of humans) can walk up right
What is the earliest member of the genus Homo?
Homo habilis; Overall change in skull structure with this change in diet such as disappearance of saggital crest since it migrates down lower towards jaw.
First group for widespread use of stone tools-Oldowan tools = scrape meat off bone.
Very good incisors for chewing meat; molars get smaller.
Diet goes towards a more meat based diet instead of the vegetarian diet from Australopithecus africanus, therefore, bigger brains
What is the evidence that Ardipithecus ramidus walked upright and climbed trees?
Human grasp and dexterity inherited almost directly from our last common ancestor with chimps.
mosaic pelvis; useful for both climbing and upright walking
rigid foot with an opposable big toe used for climbing in trees
What is the relationship between Old World and New World Monkeys?
New world: flat face, wide nostrils, prehensile tail, all arboreal
Old world: long snout, close nostrils, non-prehensile tail, partly arboreal
both came from anthropoid lineage
What is the relationship between skin color, sun exposure, and vitamin-D uptake?
Skin pigmentation and thus color is created by the amount of sunlight we receive over a long period of time dealing with the amount of UVA protection we need or Intake of vitamin D.
What is the significance of the shape of the pelvic canal in comparison of a modern
woman and "Lucy" (Australopithecus afarensis)?
The Lucy pelvic structure was wider or oval shaped; as opposed to the modern pelvic canal which is much rounder for larger brain cavity birth
What event nearly led to the extinction of Humans?
800,000 years ago climate changed; Africa population almost went extinct
Climate Change Event
What primate features had profound consequences on human evolution?
Good eyesight, bipedal (movement of foramen magnum), more efficient food source
What was the diet of Ardipithecus ramidus – what is the evidence?
Loss of canines shows they were herbivores and non aggressive males
What were the robust Australopithecines? What was their diet? Did they co-exist
with H. habilis? Why did they go extinct?
They existed, lived at same time, but went extinct and didn’t eat same food as we did so they went extinct
When and where did Homo sapiens evolve?
From a single African female 195,000 ya in Africa
What is the current opinion about whether Neanderthals might have interbred with
animals with thumbs, can see in 3-D, able to carry things, greater parental care, social, groom each other
consist of three families: great apes, lesser apes, hominids; diverged from Old World monkeys
descendant of Homo Heidelbergensis; cold-adapted; short and stocky; large nosed; long, low, thick skull; speech capabilities; good hunters; artwork
hominid footprints preserved in volcanic ash; proved they were bipedal at least 3.5mya
hole in bottom of skull where spinal cord recedes; evidence of bipedal, upright
order of mammals that includes whales, porpoises, and dolphins
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