2. Organisms inhabiting the earth
have changed overtime, their
structures, traits, and abilities
allowed them to adapt and
survive in their environment.
3.
4. SOURCES OF EVIDENCE FOR
EVOLUTION
EVIDENCE FROM FOSSIL RECORDS
EVOLUTIONARY PATTERNS FROM
COMPARATIVE ANATOMY
EVIDENCE FROM EMBRYONIC
DEVELOPMENT
5. Evidence from Fossil Records
• Fossils are examples of evidences that
paleontologists use in studying
evolution.
• Latin word FOSSILIS – “Dug up”
• They are traces of organisms that lived
in the past and were preserved by
natural process or catastrophic events.
6. Evidence from Fossil Records
• They can be remains of organisms
which include bones, shells, teeth and
also feces embedded in rocks, peat,
resin, and ice.
• Paleontologist is a person who studies
fossils.
7. Evidence from Fossil Records
• Most fossils were commonly found in
sedimentary rocks.
• Types of Fossils; Body fossils reveal
the structure of an organism, while
trace fossils reveal the activities of
organisms.
8. Importance in studying fossils:
• The fossil record indicates that
different life forms have existed at
different times revealing the evolution
of life on Earth.
• Fossils and rock types serve as clues to
determining ancient environments.
• Finally, fossils are the most practical
way of telling time in geology
13. Analyze the table above. Which is assumed to
be the oldest organism?
14. Analyze the table above. Which is assumed to
be the oldest organism?
• The oldest organism in the list are the
trilobites. They lived during Paleozoic
Era, in the Silurian and Ordovician
period.
15. In what era can you possibly find the most
recent fossil?
16. In what era can you possibly find the most
recent fossil?
• Cenozoic Era, the recent fossil may be
found in the uppermost layer of the
rock.
17. Do you think there are organisms that lived
during the Cambrian Period?
18. Do you think there are organisms that lived
during the Cambrian Period?
• Yes. Rock layers in the Cambrian period
also have traces /imprints of mollusks
that lived during that time. Most of
them were invertebrates.
19. When do you think did the present day humans
first appeared on earth?
20. When do you think did the present day humans
first appeared on earth?
• Cenozoic Era, the fossil of the first
human was found during this Era.
21. Determining the age of the fossil
• Absolute Dating – determining the
actual age of a rock or fossil using
radioactive dating.
– Example: Trilobite fossil is 489 million years old.
• Relative Dating – determining which
rock, fossil, or event came first, second,
third, etc.
– Example: Trilobite fossil is older than the dinosaur
tooth fossil
25. What is Comparative Anatomy?
• Comparative anatomy is the study of
similarities and differences in
the anatomy of different species.
26. Concepts of comparative anatomy are:
• HOMOLOGOUS - Structures from
different species which have similar
internal framework, position, and
embryonic development are considered
to be homologous.
27.
28. Concepts of comparative anatomy are:
• ANALOGOUS - Structures of unrelated
species may evolve to look alike,
because the structure is adapted to
similar function.
• same function but different in origin.
29.
30. Evidence from Embryonic
Development
Studies show that species that are
closely related exhibit similar
embryonic development. Even when in
the adult stage, the organisms are
quite different.
33. • Important names in the history of
theory of evolution are:
– Jean Baptiste Lamarck.
– Charles Darwin.
34. Jean Baptiste de Lamarck
• Jean Baptiste de Lamarck was the first
evolutionist to believe that organisms
change over time.
• He develops Three theories:
– The Theory of Need which states that
organisms change in response to their
environment.
– The Theory of Use and Disuse; which
according to Lamarck, organs not in use
will disappear while organs in use will
35. Jean Baptiste de Lamarck
• He develops Three theories:
– The Theory of Need which states that
organisms change in response to their
environment.
– The Theory of Use and Disuse; which
according to Lamarck, organs not in use
will disappear while organs in use will
develop.
– The Theory of Acquired Characteristics.
36. Jean Baptiste de Lamarck
– The Theory of Acquired Characteristics.
• Lamarck believed that giraffes before
have short necks, but because of the
need to survive and in order to reach
tall trees for food, they kept stretching
their necks until these became longer
and able to reach taller trees.
37. If you change the color of your
hair from black to blond, do you
think your child can inherit the
blond color of your hair?
38. A young lady keeps on using
whitening soap and becomes
fair? Can her child inherit her
acquired fairness?
39. Many scientists rejected the
theories of Lamarck. They
understood that if there were
changes in cell or body structure,
there could be changes in the
genetic information of the
species.
40. Charles Darwin
• Theory of Evolution – Natural Selection
– According to Darwin, giraffe species
originally had varying neck lengths but
natural selection favored the survival of
giraffes with longer necks that could feed
on taller trees that were available. Giraffes
with short neck were eliminated due to
lack of accessible food supply.
41. Darwin’s Belief’s
• Survival of the fittest OR
natural selection
– Food and resources are
limited
• So organisms have to
COMPETE to get them
(lions fight for food,
space, mates …)
• OVER PRODUCE too many
organisms
• Not all offspring will
survive only the MOST FIT
(not always the strongest!)
42. Natural Selection
• How does Selection occur?
– Selection of the most fit can occur
from several factors:
•Variations exist among
individuals in a population
•Competition for limited resources
•Overpopulation
•Predation/Disease
43. Darwinian Natural Selection
• Three conditions necessary for
evolution by natural selection to occur:
– Natural variability for a trait in a population
– Trait must be heritable
– Trait must lead to differential reproduction
• A heritable trait that enables
organisms to survive AND
reproduce is called an adaptation
46. Biodiversity is a term that
describes how varied living things
are in a specific area.
47. Organisms are part of biodiversity and may be
economically and ecologically valuable. thus
making the ecosystem balance and stable.
– Their products are source of food,
medicine, clothing, shelter, and energy.
– Some species maintain the quality of
natural bodies of water;
– some prevent soil erosion and floods,
– cycle minerals in the soil and absorb
pollutants.
– Others feed on insects and pests which
control the population of organisms in a
certain environment
48. The value of species can be divided
into various categories:
• 1. Direct economic value
• The species is considered to have direct
economic value if their products are
sources of food, medicine, clothing,
shelter, and energy.
– For example, some medicines being used
nowadays have formulations extracted
from plants or animals.
49. The value of species can be divided
into various categories:
• Indirect economic value
• A species has an indirect economic
value if there are benefits
produced by the organism without
using them.
– For example, certain species maintain the
chemical quality of natural bodies of water,
prevent soil erosion and floods, cycle
materials in the soil, and absorb pollutants.
50. The value of species can be divided
into various categories:
• Aesthetic value
• A lot of species provides visual or
artistic enjoyment, like a forested
landscape and the calming beauty of a
natural park; or they may be used for
spiritual meditation like the Prayer
Mountains.
51. Limiting Factors that depend on
population density
• Diseases and parasites – Infectious
diseases and parasites spread faster in
densely populated areas.
• Competition for resources – Organism
with better adaptations to obtain (food)
resources will be able to reproduce
more often, and its population will
grow.
52. Limiting Factors that depend on
population density
• Predation - plenty of prey are available,
predators will be able to eat sufficiently,
thus have energy to reproduce much,
and increase their numbers. The
population of their prey will begin to
decrease as more and more of them are
eaten.
53. Limiting Factors that depend on
population density
• Emigration - Emigration occurs when,
as a population approaches its carrying
capacity, and individual organisms leave
and go to a new area where they can
find enough resources for survival and
reproduction. This will obviously cause
a decrease in the amount of organisms
in a population.
63. Philippines
• biologically richest country in the world
• Has both aquatic and terrestrial
ecosystems
• high degree of endemism, meaning
high numbers of native species of flora
and fauna are found only in tropical
communities.
64. ….but
• We have all these rich natural biological
resources but we have not truly
protected them.
• We are losing this global heritage due
to habitat destruction, overuse and
pollution.
65. • Our coral reefs, where the fishes lay
eggs, are badly damaged by destructive
fishing methods such as muro-ami,
dynamite and fine nets in fishing
• people hunt animals, collect plants, and
sell corals and exotic animals for
• livelihood, and other activities that
cause the population of these
organisms to decrease at a faster rate.
66. • The rate of development in some parts
of the country is extraordinary.
• The natural landscape has been
changed by tall buildings,
establishments, housing projects,
expressways, railway systems and
overpasses. Other reclaimed areas have
been converted into industrial
structures and techno parks.
