ThursdayNovember 29,

2012(The Phanerozoic Eon:The Cenozoic Era – The Rise of Mammals and

Flowering Plants)

The Launch PadThursday, 11/29/12

What was happening to the continental land masses during

the Mesozoic Era?

Which type of animal was dominant during the Mesozoic

Era?

Pangaea began its breakup into the northern Laurasia and southern Gondwana sub-

supercontinents. Parts of North America became submerged under a shallow sea.

The reptiles took the place of the amphibians as dominant vertebrates. Birds began to evolve.

Mammals hid in holes.

Announceme

ntsHappy Cute Dog Day!

Assignment Currently Open

Summative or

Formative?Date Issued Date Due Date Into

GradeSpeed Final Day

Quiz 11 S1 11/9 11/9 11/30Lab – The Geologic

Time Scale F3 11/14 11/16 11/30

Quiz 12 S2 11/16 11/16 12/7WS - The

Precambrian Eon: Formation of

Continents and Steps Leading to Higher Life Forms

F4 11/26 11/30 11/30

WS - The Phanerozoic Eon:

The Paleozoic Era - Life Explodes

F5 11/27 11/30 11/30

WS - The Phanerozoic Eon:

The Mesozoic Era – The Age of Reptiles

F6 11/28 12/7 12/7

Recent Events in ScienceFor Some Feathered Dinosaurs, Bigger Not Always Better

Giant plant-eating theropods (close relatives of both T. rex and today's

birds) lived and thrived alongside their meat-eating cousins.

Now researchers have started looking at why dinosaurs that abandoned meat in favor of vegetarian diets got so big, and their results may call conventional wisdom about plant-eaters and body

size into question.Scientists have theorized that bigger

was better when it came to plant eaters, because larger digestive tracts would allow dinosaurs to maximize the nutrition they could extract from high-

fiber, low-calorie food.Therefore, natural selection may have

favored increasing body sizes in groups of animals that went meatless.

Read All About It!

www.sciencedaily.com/releases/2012/11/121128093254.htm

The Phanerozoic Eon The Cenozoic Era

The Cenozoic Era is the current and most recent of the three Phanerozoic eras,

following the Mesozoic Era and covering the period from about 66 million years

ago to the present.

The era began in the wake of the Chicxulub extinction event at the end of the Cretaceous that saw the demise of the last non-avian dinosaurs, as well as other terrestrial and marine flora and

fauna.

The Cenozoic is also known as the Age of Mammals, because the extinction of

many groups allowed mammals to greatly diversify.

The Cenozoic is divided into three periods:

The Paleocene, Neocene, and Quaternary.

The Phanerozoic Eon Early in the Cenozoic, following the

Chicxulub event, the planet was dominated by relatively small fauna,

including small mammals, birds, reptiles, and amphibians.

It did not take long for mammals and birds to greatly diversify in the

absence of the large reptiles that had dominated during the Mesozoic.

The Phanerozoic Eon Some birds grew larger than the

average human, and were known as the "terror birds," which were

formidable predators.

Mammals came to occupy almost every available niche (both marine

and terrestrial), and some also grew very large, attaining sizes not seen in

most of today's mammals.

The Phanerozoic Eon Climate-wise, the Earth had begun a drying and

cooling trend, culminating in the glaciations of

the Pleistocene Epoch.

The continents also began looking roughly familiar at this time and moved into their current positions.

The Phanerozoic Eon During the

Cenozoic, mammals proliferated from a few small,

simple, generalized forms into a diverse collection

of terrestrial, marine, and flying animals, giving this

period its other name, the Age of Mammals, despite the

fact that birds still outnumbered mammals two

to one.

The Phanerozoic Eon The Cenozoic is just as much the age of savannas, the age of co-

dependent flowering plants and insects, and the age of

birds.

The Phanerozoic Eon Grass also played a very

important role in this era, shaping the evolution of the birds and

mammals that fed on it.

One group that diversified significantly in the Cenozoic as

well were the snakes.

Evolving in the Cenozoic, the variety of snakes increased tremendously, resulting in

many colubrids, following the evolution of their current primary

prey source, the rodents.

The Phanerozoic Eon In the earlier part of the Cenozoic, the

world was dominated by the gastornid birds, terrestrial crocodiles li

ke Pristichampsus, and a handful of primitive large

mammal groups like uintatheres, meso

nychids, and pantodonts.

The Phanerozoic Eon In the earlier part of the Cenozoic, the

world was dominated by the gastornid birds, terrestrial crocodiles li

ke Pristichampsus, and a handful of primitive large

mammal groups like uintatheres, meso

nychids, and pantodonts.

The Phanerozoic Eon But as the forests began to recede

and the climate began to cool, other mammals took over.

The Cenozoic is full of mammals both strange and familiar,

including halicotheres, creodonts, whales,

primates, entelodonts, saber-toothed cats,

mastodons and mammoths, three-toed horses,

giant rhinoceros like Indricotherium, and brontotheres.

The Phanerozoic Eon But as the forests began to recede

and the climate began to cool, other mammals took over.

The Cenozoic is full of mammals both strange and familiar,

including halicotheres, creodonts, whales,

primates, entelodonts, saber-toothed cats,

mastodons and mammoths, three-toed horses,

giant rhinoceros like Indricotherium, and brontotheres.

The Phanerozoic Eon But as the forests began to recede

and the climate began to cool, other mammals took over.

The Cenozoic is full of mammals both strange and familiar,

including halicotheres, creodonts, whales,

primates, entelodonts, saber-toothed cats,

mastodons and mammoths, three-toed horses,

giant rhinoceros like Indricotherium, and brontotheres.

The Phanerozoic Eon But as the forests began to recede

and the climate began to cool, other mammals took over.

The Cenozoic is full of mammals both strange and familiar,

including halicotheres, creodonts, whales,

primates, entelodonts, saber-toothed cats,

mastodons and mammoths, three-toed horses,

giant rhinoceros like Indricotherium, and brontotheres.

The Phanerozoic Eon But as the forests began to recede

and the climate began to cool, other mammals took over.

The Cenozoic is full of mammals both strange and familiar,

including halicotheres, creodonts, whales,

primates, entelodonts, saber-toothed cats,

mastodons and mammoths, three-toed horses,

giant rhinoceros like Indricotherium, and brontotheres.

Figure 12.35The Cenozoic heralded the

development of the marsupial

family of mammals.

By contrast, this is a placental mammal.

The Phanerozoic Eon What is the difference between a placental

mammal and a marsupial mammal?

The Phanerozoic Eon The Cenozoic could also be called the “Age of

Flowering Plants.”Flowering plants (angiosperms) strongly influenced

the evolution of both birds and herbivorous mammals throughout the Cenozoic.

Figure 12.34A

WorksheetThe Phanerozoic Eon:

The Cenozoic Era – The Rise of Mammals and

Flowering Plants