Macroevolution and the Early Primates - PowerPoint PPT Presentation

Loading...

PPT – Macroevolution and the Early Primates PowerPoint presentation | free to download - id: 6ddb33-MmUxO



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Macroevolution and the Early Primates

Description:

Chapter 6 Macroevolution and the Early Primates – PowerPoint PPT presentation

Number of Views:7
Avg rating:3.0/5.0
Date added: 12 September 2019
Slides: 47
Provided by: StacyS156
Learn more at: http://famuonline.wikispaces.com
Category:

less

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

Title: Macroevolution and the Early Primates


1
Chapter 6
  • Macroevolution and the Early Primates

2
Chapter Preview
  • What Is Macroevolution?
  • When and Where Did the First Primates Appear, and
    What Were They Like?
  • When Did the First Monkeys and Apes Appear, and
    What Were They Like?

3
Macroevolution and the Process of Speciation
  • macroevolution evolution above the species
    level (i.e. the creation of new species)
  • speciation the process of forming new species.

4
Macroevolution and the Process of Speciation
  • Since species are populations who are capable of
    interbreeding and producing viable and fertile
    offspring
  • To create new species, populations must separate
    through reproductive isolating mechanisms
    biological and behavioral factors that separate
    breeding populations and prevent gene flow

5
Reproductive Isolating Mechanisms For Class
Discussion
  • What types of biological (morphology, genetics)
    and behavioral factors could lead to reproductive
    isolation?

6
Macroevolution and the Process of Speciation
  • Cladogenesis speciation occurs when
    descendants of an ancestral population become
    reproductively isolated
  • Anagenesis speciation through the gradual
    accumulation of advantageous traits

7
The Shape of Macroevolution
(A) cladogenesis (B) convergent evolution (C)
parallel evolution
8
Cladogenesis (Divergent Evolution)
9
Convergent Evolution
Ancestral populations are very distantly related
10
Convergent Evolution
Ancestral populations are very distantly related
11
Parallel Evolution
Ancestral populations are more closely related
12
The Timing of Evolution
Gradual evolution suggested by Charles Darwin,
physical traits change slowly and consistently
over time Punctuated equilibria suggested by
Stephen Gould, evolution occurs via long periods
of stability or stasis punctuated by periods of
rapid change.
13
The Timing of Evolution
Punctuated Equilibrium
Gradualism
14
The Timing of Evolution and Genetics
Change in the timing of growth and development --
heterochrony, can be responsible for changes in
the shape or size of a body part. There are
also homeobox genes that are responsible for
large-scale effects on the growth and development
of the organism. They may be linked to patterns
of evolutionary timing predicted by the
punctuated equilibria model.
15
Visual Counterpoint For Class Discussion
The differences between chimpanzees and humans
are sometimes linked to a type of heterochrony
known as neotony (the retention of juvenile
traits). Which juvenile chimp traits do you
think we have retained?
16
Constructing Evolutionary Relationships
  • Evolutionary relationships can be traced through
  • homologous traits originate from a common
    ancestor
  • analogous traits reflect similar environmental
    pressures not ancestry

17
Constructing Evolutionary Relationships
18
Constructing Evolutionary Relationships
  • The legs of prosimians and humans do not have a
    close evolutionary relationship they are a
    result of the convergent evolution of homologous
    traits.

19
Constructing Evolutionary Relationships
  • In addition to homologous and analogous traits,
    evolutionary relationships can be traced through
  • (1) Derived traits traits found in a group of
    organisms that did not exist in ancestral
    populations.
  • (2) Ancestral traits traits possessed by an
    organism or group of organisms due to shared
    ancestry.

20
  • Macroevolution of the Early Primates

21
Continental Drift and Geological Time

Because primate evolution extends so far back in
time, paleoanthropologists reconstruct primate
evolution in conjunction with information about
the geological history of the earth.
22
Continental Drift and Geological Time

Continental drift According to the theory of
plate tectonics, the movement of continents
embedded in underlying plates on the earths
surface in relation to one another over the
history of life on earth. Such changes can also
affect the climate and environment.
23
Early Mammals
Mammals appear as early as 190 million years
ago. Around 70 mya, the earth began to
experience sever climatic changes and many of the
larger reptiles and dinosaurs went extinct,
opening new environmental niches for
mammals. Mammal-like animals were preadapted to
advantages of these changes and underwent an
adaptive radiation -- a rapid increase in the
number of related species following a change in
their environment.

24
Early Mammals Adaptive Traits
  • Mammals are homeotherms - animals that maintain
    a relatively constant body temperature despite
    environmental fluctuations.
  • By contrast, reptiles are isotherms -animals
    whose body temperatures rise or fall according to
    the temperature of the surrounding environment.

25
Early Mammals Adaptive Traits
  • Mammals are k-selected reproduction involves
    the production of relatively few offspring with
    high parental investment in each.
  • Other animals are more r-selected - reproduction
    involves the production of large numbers of
    offspring with relatively low parental investment
    in each.

26
The Proto-Primates (65 mya)
  • The first primate-like mammals, or
    proto-primates, were roughly similar to squirrels
    and tree shrews in size and appearance. 
  • The existing, very fragmentary fossil evidence
    (mostly from North Africa) suggests that they
    were adapted to an arboreal way of life in warm,
    moist climates. 

27
The Rise of the Primates
  • The rise of primates appears to be an adaptive
    radiation linked to the spread of flowering
    plants (angiosperm radiation) and pollinating
    insects.

28
The Rise of the Primates
  • (1) arboreal hypothesis a hypothesis for
    primate evolution that proposes that life in the
    trees was responsible for enhanced visual acuity
    and manual dexterity in primates.
  • (2) visual predation - a hypothesis for primate
    evolution that proposes that hunting behavior in
    tree-dwelling primates was responsible for their
    enhanced visual acuity and manual dexterity.

29
Timeline of Primate Evolution
30
True Primates - Early Prosimians
  • Their bones have been found in 55 million year
    old geological deposits in North
    America-Europe-Asia (Laurasia) and Africa.
  • The rainforest environments were warm and wet.
  • They were somewhat squirrel-like in size and
    appearance, but apparently they had grasping
    hands and feet that were increasingly more
    efficient in manipulating objects and climbing
    trees.

31
True Primates - Early Prosimians
  • Early prosimians had postorbital bars and
    relatively long snouts.

32
Early Strepsirhines
  • Fossils of lemur and loris ancestors are found in
    North America, Europe, Asia, and possibly Africa.
  • Main Features small eye sockets, elongated
    snouts, cheek teeth adapted for folivorous or
    frugivorous diets, and relatively large body mass
    (greater than 1 kg).

33
Early Haplorhines
  • Fossils of haplorhines (ancestors of tarsiers and
    anthropoids) are found in North America, Europe,
    Asia, and possibly Africa.
  • Main Features large eye sockets, shortened
    snouts, cheek teeth adapted for insectivorous or
    frugivorous diets, and relatively small body mass
    (less than 500 g)

34
Oligocene Anthropoids
  • By the Oligocene period, prosimians are
    out-competed by anthropoids (except in
    Madagascar).
  • Deposits in Fayum (Egypt) and other parts of
    North Africa, show the development of anthropoids
    some with the dental formula similar to
    Platyrrhines (2-1-3-3) and others with the
    Catarrhine dental formula (2-1-2-3)

35
Aegyptopithecus
  • the size of a large domestic cat (13-20 pounds)
  • fruit and seed eating forest tree-dweller
  • had fewer teeth, less long snout, larger brains,
    and increasingly more forward-looking eyes than
    the prosimians

36
The Origin of New World Monkeys
  • The earliest platyrrhine fossils are found in
    South America and are only about 25 million years
    old.
  • Both platyrrhines and catarhines originated from
    prosimian ancestors although anthropologists
    still debate if it was the same ancestor.
  • A possible African origin for platyrrhines is
    suggested by the rafting and island hopping
    hypotheses but the geological evidence for these
    is inconclusive.

37
(No Transcript)
38
Miocene Apes
  • Evolutionary relationships are based on a
    molecular clock - a hypothesis that dates of
    divergences among related species can be
    calculated through an examination of the genetic
    mutations that have accrued since the divergence.

39
Proconsul
  • existed from 27 to 17 million years ago in
    Africa
  • ranged in size from 22-84 lbs (10-40 kg)
  • its monkey-like features included thin tooth
    enamel, a light build with a narrow chest and
    short forelimbs, and an arboreal quadrupedal
    lifestyle
  • its ape-like features are its lack of a tail,
    ape-like elbows, and a slightly larger brain
    relative to body size

40
Proconsul
41
Dryopithecus
  • existed from 12 to 9 million years ago in
    Eastern Africa and Eurasia
  • had a Y-5 cusp arrangement on its molar teeth
    typical of hominoids

42
Dryopithecus
43
Sivapithecus
  • existed from 12.5 to 8.5 million years ago in
    India and Pakistan
  • possible ancestor of the orangutan and
    gigantopithecus already had separated from the
    common ancestor of chimpanzees and gorillas

44
Sivapithecus
45
Gigantopithecus
  • existed from 1.0 million to 300,000 years ago in
    China, India and Vietnam
  • it stood about 10 feet (3 meters) tall and
    weighed as much as 1200 pounds (545 kg)
  • Gigantopithecus was probably a quadruped and an
    herbivore, existing on a diet primarily of
    bamboo, possibly supplemented with seasonal fruits

46
Gigantopithecus
About PowerShow.com