The document discusses the evolution and characteristics of elephants, detailing their social behavior, physical features such as the trunk, and communication methods. It outlines the evolutionary timeline of elephants from early ancestors like moeritherium to modern species, highlighting key changes in size, dentition, and tusk development. Additionally, it describes the lineage of elephants and provides insight into side lines of evolution as well as special facts about their anatomy and tooth replacement.

1. TKR Presents
EVOLUTION OF ELEPHANT

2. INTRODUCTION
 Elephants are giant terrestrial mammals.
 Characteristic feature of body is presence of
trunk.
 Elephant shows social behavior or lives in society.
 Elephants distantly present communicate via
infrasound.
 Elephants are commonly found in Africa and Asia.
 Male elephants are generally taller than females.
 Elephants have plantigrade posture.
*Evolution is development process from simple
form of life to complex.

3. POSITION OF ELEPHANT IN
PHLOGENETIC TREE
 KINGDOM : Animalia
 PHYLUM : Chordata
 CLASS : Mammalia
 ORDER: Proboscidea

4. PROGENY LINES WITH TIME
PERIOD
TIME PERIOD MAIN LINES SIDE LINES
EOCENE Moeritherium
OLIGOCENE Palaeomastodon Phiomia
True Mastodon
MIOCENE Bunomastodon Miomastodon
Deinotherium
PLIOCENE Tetralophodon
Steglophodon
Stegodon
Trilophodon
Phiomastodon
PLEISTOCENE Mastodon
Stegomastodon
RECENT Mammoth
Loxodonta
Elephas

5. DIAGRAMMATIC
REPRESENTATION
OF EVOLUTIONARY LINES

6. EVOLUTIONARY TRENDS
 Increase in size and weight( elongation of limb
bones and enlarged skull).
 Development and elongation of proboscis.
 Modification of second pair
 of incisors into tusks.
 Modification of dentition from bunodont (molar
teeth with rounded cusps) to lophodont (grinding
surface of molar teeth with transverse sutures).

8. MAIN LINES IN EVOLUTION
1.MOERITHERIUM
* Swamp dweller.
* About size of pig.
* Bunodont dentition.
* No proboscis.
* Snot elongated.
* Elongated body.
* Short legs.
*First lower incisor small whereas second lower
incisor large suggesting development of
tusks in later stages from it.

9. 2. PALAEOMASTODON
* Arose from moeritherium.
* During oligocene.
* Proboscis short.
* Upper tusks more elongated.
*Lower tusks are short.
* Gave rise to two lines
Bunomastodon and Mastodon.
3. BUNOMASTODON
* Arose from Palaeomastodon.
* Tusks on both jaws.
* Proboscis long.
* Gave rise to several lines.

10. 4. TETRALOPHODON
* Lived during pliocene.
* Four cusps in four milk teeth and in first and
second
molar teeth.
* Proboscis similar to modern elephants.
* Four tusks present.
* Molar high crowned.
* Each molar with four crossing cusps.
* Gave rise to two lines : Stegomastodon (side
line) and Steglophodon (main line).

11. 5. STEGLOPHODON
* Lived in pliocene.
* Early records seen in Japan.
* Early specimen showing bunodont indicating
its
origin from bunodont ancestors.
* Only upper tusks present.
* Lower tusks absent.

12. 6. STEGODON
* Widely believed to be originated from steglophodon.
Some believe this occurred in Africa and others believe it
to have occurred in Asia.
* Lived upto pleistocene.
* Skull shortened.
* Anterior part of mandible shortened.
* Long proboscis.
* Tusks are huge and generally lower
tusks absent.
* Teeth were high crowned.
* Traditionally believed to be ancestor
of Loxodonta, Elephas and
Mammoths.

13.  Mammoth, Elephas and Loxodonta, all three are
under same subfamily Elephantinae.
 All three of them are hypsodont.
7. MAMMOTH
* Like modern elephants but extinct.
* Lived during pleistocene.
* Strongly curved and twisted tusks.
* Plate number and lamellar frequency in teeth
increased with time.
* Mammoth were generally adapted to cold
environment.

14. 8. MODERN ELEPHANT
* Represented by two genera, African elephant
Loxodonta and Asian elephant Elephas.
* Loxodonta have cheek teeth with high crowns.
* Loxodonta is only taxa with thick rhomb shaped
lophs.
* Feeding pattern is browsing and grazing.
* Early species of Elephas have low crown, low
lamellar frequency and low enamel.
* African elephants are characterized by great
palmleaf-like ears, while Asian elephants ears
are smaller.

15. SIDE LINES IN EVOLUTION OF
ELEPHANT
1.PHIOMIA
*Oligocene period.
* Size double of Moeritherium.
* Tusk present in both jaws.
* Skull large with air cells.
* Some evolutionists believed
it to be in main line of evolution
while others considered it
in side line evolution.

16. 2. DEINOTHERIUM
* Side line evolution.
* Miocene period.
* Lived in swamps.
* Proboscis present
* Dentition lophodont present as an adaptation to leaf eating.
* First two premolars absent.
* Since only two lobes present in second molar teeth whereas three
lobes in second molar of palaeomastodon, its believed to have
more primitive ancestor.
* Only proboscidean in which upper pair of tusks absent.
* Tusks curved downward and backward.
* Size of deinotherians increased with time.
* Cause of extinction is that they couldn’t change their eating habits
with changing environment especially during winter season.

17. 3. MASTODON
* Size of elephants.
* Lived from upper oligocene to pleistocene.
* Molar bilophodont.
* Lower tusks absent.
* Upper tusks curved as modern elephants.
* Air spaces in skull.

18. 4. TRILOPHODONT
* Present during pliocene.
* Size of modern elephant.
* Four tusks present.
* Upper tusks elongated and
lower tusks short.
* First two molars have three pairs of
transversely arranged cusps.
* Molars low crowned.

19. SPECIAL FACTS ABOUT
ELEPHANTS
 Trunk is formed from fusion of nose and upper lip.
 Air cavities are present in skull of elephant.
 Incisors form tusks.
 There are 6 sets of teeth throughout the life of
elephant.
 Two types of tooth replacement, horizontal and
vertical.
 In vertical replacement, milk teeth are replaced by
premolars and premolars erupt later and remain
in same place.
 In horizontal replacement, teeth move forward in
mandible, worn out teeth drops out of mouth and
new teeth arose at back of mandible.

20. THE END