The Cenozoic - PowerPoint PPT Presentation

Loading...

PPT – The Cenozoic PowerPoint presentation | free to view - id: 15a54-MjVhM



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

The Cenozoic

Description:

Multituberculates - now extinct - rodent-like mammals who lived from Jurassic to ... marsupial dogs, cats, rodents, even a lion-like marsupial with retractable claws ... – PowerPoint PPT presentation

Number of Views:176
Avg rating:3.0/5.0
Slides: 61
Provided by: DavidM5
Category:
Tags: cenozoic | lion | monkey

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: The Cenozoic


1
TheCenozoic
2
Tectonics
Tectonics of the Mesozoic and Cenozoic
3
Major Mammal Groups
  • Multituberculates - now extinct - rodent-like
    mammals who lived from Jurassic to Oligocene and
    were probably outcompeted by modern rodents
  • Monotremes - only three species still alive,
    duck-billed platypus and two species of echidna
    (long-nosed and short-nosed spiny anteaters), all
    found in Australia and New Guinea

4
Major Mammal Groups
  • Metatheria (Marsupials) - Important group of
    mammals - originated in Middle Cretaceous as
    opossum-like organisms. They give birth to live,
    immature offspring.
  • Eutheria (Placental mammals) - Give birth to live
    young, often very mature functional organisms.
    Provide support for developing offspring through
    placenta connecting it to mothers blood supply.

5
Echidna - a Monotreme
6
Platypus - a Monotreme
7
Platypus - a Monotreme
8
Monotremes
  • A mix of primitive, standard mammal, and advanced
    features
  • They lay eggs like birds or reptiles
  • They support their young with milk
  • They have standard mammal skull structure
  • They have very specialized parts (e.g. nose
    parts, webbed feet)
  • Platypuses are even venomous!

9
Monotremes
  • Monotremes have no teeth as adults (some have
    teeth as young)
  • Eggs are small (1/2 to 3/4 inch in diameter) and
    leathery in platypus only the left ovary works
  • Probably split from other mammals sometime in
    Mesozoic - the earliest fossil is from the
    Cretaceous
  • Some possible monotreme fossils found in
    Argentina - could they have been widespread at
    one time?

10
Kangaroo - a Marsupial
11
Tasmanian Wolf - a Marsupial
12
Marsupials
  • Originated in North America around Middle
    Cretaceous
  • Rapidly spread to South America and then to other
    parts of the world (scattered fossils found in
    Europe, Asia, the Americas), but faded away from
    North America by the Miocene when placental
    mammals entered the scene
  • Marsupials recolonized the Americas during the
    Pliocene.

13
Marsupials
  • Young are born after only 8-40 days of gestation
  • What is the problem they are trying to solve?
  • Rejection by mothers immune system
  • Whats better, marsupial reproduction or
    placental?
  • Not clear, but placentals have outcompeted
    marsupials most places where they have been in
    conflict

14
Marsupials
  • Lots of forms of marsupials which are parallel to
    placental forms have existed at various times
  • There have been big marsupial grazers, marsupial
    dogs, cats, rodents, even a lion-like marsupial
    with retractable claws
  • Kangaroos and their relatives are an exception -
    no known parallel among other mammals. Theyve
    been more diverse in the past too - one ten-foot
    high species existed.

15
Placental Mammals
  • Includes most mammals we think about - whales,
    bats, elephants, shrews, and armadillos
  • All give birth to live offspring after extended
    gestation
  • Sometimes offspring are fairly helpless for long
    periods after birth other times offspring are
    fairly mobile
  • All require mothers milk for support for at
    least a while (like other mammals)

16
Placental Mammals
  • First showed up no later than Upper Cretaceous,
    possibly earlier (early fossils havent been
    definitively split between marsupials and
    eutherians)
  • Eutherians were widespread in Asia by the K-T
  • Many modern groups were around at or near the
    start of the Cenozoic, and all modern groups were
    in place by the end of the Miocene.

17
How do we fit into all of this?
  • Humans are placental mammals, evolved from a
    small subgroup of rodent-like ancestors
  • Before we continue, lets make sure we know our
    taxonomic address...

18
Kingdom Animalia
Animals are a very diverse group. Most are
mobile at some level, but not all can relocate
(e.g. sponges, bryozoans). All must consume
external nutrients to survive, although some have
developed symbiotic relationships with plants or
algae.
19
Phylum Chordata
All chordata share the following
characteristics pharyngeal slits - a series of
openings that connect the inside of the throat to
the outside of the "neck". These are often, but
not always, used as gills. dorsal nerve cord - a
bundle of nerve fibers which runs down the
"back". It connects the brain with the lateral
muscles and other organs. notochord -
cartilaginous rod running underneath, and
supporting, the nerve cord. post-anal tail - an
extension of the body past the anal opening.
20
Subphylum Vertebrata
All vertebrates share the following
characteristics vertebrae - all vertebrates have
a hard spinal column encasing their
notochords neural crest cells - these cells
migrate throughout the body during development,
distributing nerve bundles everywhere cartilage -
all vertebrates have cartilage in addition to or
in place of bone dermal and endoskeletal bone -
all vertebrates have bones made of calcified
tissue or cartilage in their bodies well-defined
head centrally-located heart acute sensory organs
21
Tetrapoda
Tetrapoda, including all reptiles and mammals,
have four limbs. In some (like snakes and
dolphins), the four limbs have been highly
modified, but they are still present in the
skeletal structure. All tetrapoda have digits at
the end of their main limbs
22
Synapsida
Synapsida is a group which includes some mammals
and some mammal-like reptiles. They are
distinguished by having a single cavity in their
skulls through which muscles from the jaw
pass. Most reptiles are diapsids and have two
such cavities.
23
Class Mammalia
Almost all mammals share the following
characteristics Warm blooded - regulate
temperature from within Hairy covering - for
insulation and protection takes various forms in
different species Mammary glands - secrete milk
to nourish young
24
Subclass Eutheria
Eutheria are the placental mammals, those which
develop in the uterus of the female and obtain
liquid nourishment from a placenta.
25
Order Primates
26
Order Primates
Primates include all of the monkeys, lemurs,
tarsiers, apes, and humans. To be a primate, you
need a big head, acute sight, binocular vision,
and well-developed manipulative hands (and often
feet).
27
Family Hominidae
28
Family Hominidae
Hominids are the human-like apes, different from
the other living apes. They radiated from
existing ape species about 5-10 million years ago.
29
(No Transcript)
30
(No Transcript)
31
(No Transcript)
32
(No Transcript)
33
Lemur (Prosimian)
34
Loris (Prosimian)
35
Tarsier (Prosimian)
36
Marmoset (New World Monkey)
37
Atelinae(New World)
38
Cappuchin (New World)
39
Squirrel Monkey (New World)
40
Baboon (Old World)
41
Rhesus (Old World)
42
Vervet(Old World Monkey)
43
Langur (Old World Monkey)
44
Gibbon (Lesser Ape)
45
Orangutan(Great Ape)
46
Gorilla (Great Ape)
47
Chimpanzee (this ones a bonobo)(Great Ape)
48
Human(this ones named Brianna)
49
(No Transcript)
50
Australopithecus (Early upright hominids)
51
Hominid evolution
  • Humans and living apes used to be thought to have
    split 15-20 Ma, or even up to 30-40 Ma.
  • Some apes occurring within that time period, such
    as Ramapithecus, used to be considered as
    hominids, and possible ancestors of humans.
  • Later fossil finds indicated that Ramapithecus
    was more closely related to the orangutan, and
    new biochemical evidence indicated that the last
    common ancestor of hominids and apes occurred
    between 5 and 10 million years ago.
  • -Talk.origins FAQ

52
Australopithecus
  • Lived primarily in grasslands, seldom in forest
  • Had many grinding teeth, some large, and had
    small canines
  • Habitual biped (walked on two legs)
  • Brains were probably slightly larger than modern
    apes

53
Australopithecines
54
Australopithecines
  • Ardipithecus ramidus - oldest known human-like
    hominid (4.4 Ma). About 4 tall, possibly
    bipeds. Probably forest dwellers.
  • Australopithecus anamensis - 4.2-3.9 Ma. 21
    fossils (teeth, fragments) found in Kenya.
    Primitive skull, advanced body - probably
    bipedal. Very human-like limbs.

55
Australopithecines
  • Australopithecus afarensis - 3.9-3.0 Ma. 4-5
    tall. Apelike face (low forehead, bony ridge
    over eyes, no chin, protruding jaws). Brain size
    about 1/3 of human. Bipedal but not fast very
    muscular.
  • Australopithecus africanus - 3-2 Ma. Bipedal,
    slightly taller, bigger brain (about chimp size).
    Teeth larger than human but similar in form.

56
Australopithecines
  • Australopithecus aethiopicus - 2.6-2.3 Ma - known
    from one skull plus some other bits. Earliest
    robust australopithecine. Confusing mix of
    traits.
  • Australopithecus robustus - 2-1.5 Ma. Similar
    body to africanus, but bigger head. Flat face,
    smaller teeth except for molars - indicating
    coarse, tough food. May have used digging tools.

57
Australopithecines and Homo
  • Australopithecus boisei - 2.1-1.1 Ma. Similar to
    robustus but even bigger face and teeth, some
    almost an inch across. 530 cc brain, possibly
    same species as robustus.
  • Homo habilis - - 2.4-1.5 Ma. Handy man
    definitely used tools. Form is like
    Austalopithicines but bigger brain. 5 tall,
    100 lbs. Brain has more human structure - may
    have had rudimentary speech.

58
Genus Homo
  • Homo erectus - 1.8-0.3 Ma. Protruding jaw with
    large molars. Thick brow ridges, larger brain
    (900-1100 cc). Probably more muscular than
    earlier Homo species. Better walker than us -
    pelvis not so wide. Habilis and
    australopithecines found only in Africa, but
    erectus found in Asia, Africa, and Europe.
    Probably used fire, had sophisticated stone tools.

59
Genus Homo
  • Homo sapiens - 500,000 years ago to present.
    Started with 1200 cc brains but got bigger.
    Started with bigger teeth, but got smaller. Also
    lost brow ridges.
  • Neanderthals - 230,000 - 30,000 yrs ago - Larger
    brains than us (1450 cc) but they were larger.
    Protruding jaw, receding forehead, but very
    similar to modern humans (even considered same
    species as us sometimes). Thick bones, heavily
    muscled. Lots of weapons and tools.

60
(No Transcript)
About PowerShow.com