2. EARTH’S AGE
Earth is estimated to be 4.54 billion years
old, plus or minus about 50 million years.
Scientists have scoured the Earth
searching for the oldest rocks to
radiometrically date.
Earth’s documented history is based on the
life-forms that have existed on the planet.
3. GEOLOGIC TIME SCALE
The “calendar” for events in Earth
history
It was developed after scientists
observed changes in the fossils going
from oldest to youngest sedimentary
rocks.
They used relative dating to divide
Earth's past in several chunks of time
when similar organisms were on Earth
4.
5. PRE-CAMBRIAN
Started at the beginning of the
Earth.
For billions of years, there was no
life on the planet.
The earliest life consisted of
cyanobacteria that were able to
extract nutrition from chemicals in
seawater.
6. EONS
HADEAN
4.5 – 4.0 BYA
The planet was
characterized by a partially
molten surface,
volcanism, and asteroid
impacts.
ARCHAEAN
4 – 2.5 BYA
The Earth's crust cooled
enough that rocks and
continental plates began
to form.
PROTEROZOIC
2.5 BYA – 541 MYA
Great Oxygenation Event
Cyanobacteria completely
transformed the
atmosphere by adding free
oxygen gas (O2).
7. PHANEROZOIC EON
PALEOZOIC ERA
542 – 250 MYA
CAMBRIAN
EXPLOSION
It was when most of the
major animal groups
started to appear in the
fossil record, a time of
rapid expansion of
different forms of life
on Earth.
MESOZOIC ERA
250 – 65 MYA
“MIDDLE LIFE”
This is the time of
the dinosaurs. This
era includes the
Triassic, Jurassic,
and Cretaceous
Periods. Mass
Extinction of non-
avian Dinosaurs.
CENOZOIC ERA
65 MYA - PRESENT
“RECENT LIFE”
Ice Age covered most
parts of the Earth.
Mammals dominated the
Earth, the age of
mammals. All species of
life—including humans—
evolved into their present-
day forms over the course
of this era.
8. MASS EXTINCTIONS
ORDOVICIAN-
SILURIAN
444 MYA
Glaciation and Heating
Event
The plant life removed CO2
from the air causing global
cooling. Global warming made
the creatures unable to adapt
the temperature.
86% lost
LATE DEVONIAN
365 MYA
Algal Blooms and
Glaciation
The theory suggest algae
consumed vast amounts of
O2 in the ocean, suffocating
the marine life. Other theory
suggest that another global
cooling leads to habitat loss
of living organisms.
75% lost
PERMIAN-
TRIASSIC
252 MYA
Volcanic activity released
massive amount of CO2,
bacteria thrived. Bacteria
released methane gas that
warmed the planet. Ocean and
water became acidic, Earth
became toxic.
96% lost
9. MASS EXTINCTIONS
TRIASSIC-JURASSIC
201.3 MYA
Volcanic Activity and Asteroid
Impact
Volcanic eruptions spewed tons of
CO2 into atmosphere, this acidified
the ocean and warmed the Earth.
An asteroid or comet impact
triggered the extinction of dinosaurs.
80% lost
CRETACEOUS-PALEOGENE
66 MYA
Asteroid Impact
A widely accepted theory tells that
asteroid landed in the Yucatain
Peninsula in Mexico and wiped out
the non-avian dinosaurs. This also
caused global cooling, local fires,
earthquakes, tsunamis, and acid rain.
60-76 % lost
11. EVOLUTION
Evolution is the change in the genetic
composition of a population over
time.
The change in the characteristics of a
species over several generations.
On a larger scale, evolution can be used
to refer to the gradual appearance of
all biological diversity.
12. CHARLES DARWIN
Charles Darwin presented evidence
that many modern organisms are
descended from ancestral species
that were different.
Darwin presented a mechanism for
evolution – natural selection.
On the Origin of Species (1859)
14. NATURAL SELECTION
Natural selection occurs when
organisms with particular heritable
traits have more offspring that survive
& reproduce.
When an environment changes, or
when individuals move to a new
environment, natural selection may
result in adaptation to the new
conditions.
15. NATURAL SELECTION
Individuals do not evolve;
populations evolve.
Natural selection can only work on
heritable traits.
Acquired traits are not heritable
and are not subject to natural
selection.
18. MICROEVOLUTION
Evolution at individual species
scale.
A change of allele frequencies
in a population over a short time.
The basis for all large-scale or
macroevolution.
19. CAUSES OF MICROEVOLUTION
GENETIC DRIFT
The change in the gene
pool of a small
population due to
chance.
NATURAL SELECTION
The species that can
adapt and survive will
pass their traits to the
future generations.
GENE FLOW
Genetic exchange
due to the migration
of fertile individuals or
gametes between
populations.
20. CAUSES OF MICROEVOLUTION
MUTATION
Change in an organism’s
DNA. Mutations can be
inherited by offspring via
gametes.
NON-RANDOM
MATING
Mates are chosen on the
basis of the best traits.
22. MACROEVOLUTION
A change that occurs at or above
the species level.
It is the occurrence of large-scale
changes in the characteristics of life
resulting to evolution of higher taxa.
A change of one species into an
entirely different species -
SPECIATION
23. SPECIATION
Formation of new species.
Species – a group of organisms that
can interbreed and produce a fertile
offspring.
Factors: Natural Selection,
Continental Drift, Changes in
Environment, Mutations, and Man.
24. FACTORS OF SPECIATION
CONTINENTAL DRIFT
When the
continents separated,
the animals were
separated.
NATURAL SELECTION
The species that can
adapt and survive will
pass their traits to the
future generations.
CHANGES IN
ENVIRONMENT
Changes in the
environment forces
the species to change
for survival.
25. FACTORS OF SPECIATION
MUTATION
Change in an organism’s
DNA. Mutations can be
inherited by offspring via
gametes.
ARTIFICIAL SELECTION
Selective breeding as
practiced by humans on
domesticated plants and
animals.
28. EVIDENCES OF EVOLUTION
F – FOSSIL evidences (remains of the
ancient organisms)
A – ANATOMICAL STRUCTURE or
comparative anatomy (body parts)
M – MOLECULAR EVIDENCE
(DNA/RNA/ATP)
E – EMBRYOLOGY (embryos look similar
from one species to the next)
29. EVIDENCES OF EVOLUTION
FOSSILS
Fossils are remnants of
past life preserved in the
Earth. Complete remains,
petrifies skeletal parts,
traces of organisms.
ANATOMICAL STRUCTURES
The comparative study of the body
structures of different species of animals in
order to understand the adaptive changes
they have undergone in the course of
evolution from common ancestors.
30. EVIDENCES OF EVOLUTION
MOLECULAR BIOLOGY
similarities between biological
molecules can reflect shared
evolutionary ancestry.
Similarities in DNA, RNA,
Proteins, and Amino Acids.
EMBRYOLOGY
All vertebrate embryos exhibit
pharyngeal pouches at a certain stage
of their development. These features,
which develop into neck and face parts,
suggest relatedness.
32. TAXONOMY
Taxonomy is the science of naming,
describing and classifying organisms
and includes all plants, animals and
microorganisms of the world.
A taxon is a group of organisms in a
classification system.
Father of Taxonomy: Carl Linnaeus
developed the scientific naming system.
33. BINOMIAL
NOMENCLATURE
Binomial nomenclature is a two-
part scientific naming system.
It uses LATIN words
Scientific names always written in
italics
Composed of two parts: genus
name and species descriptor.
34. BINOMIAL NOMENCLATURE: GENUS
A genus includes one or more
physically similar species.
Species in the same genus are
thought to be closely related.
Genus name is always capitalized.
e.g Homo sapiens – Humans
Canis lupus familiaris - Dogs
35. BINOMIAL NOMENCLATURE: SPECIES
A species descriptor is the second
part of a scientific name.
Species name is always written in
lowercase.
Species name always follows
genus name; never written alone.
e.g Carlito syrichta - Philippine
Tarsier
36. SCIENTIFIC NAMES
Scientific names help scientists
to clearly communicate about
species.
Some species have very similar
common names.
Some species have many
common names.
Scientific name: Hibiscus rosa sinensis
Common names: Gumamela, Hibiscus,
Tapurang (Bis.) Shoe flower (Engl.)
37. LINNAEAN CLASSIFICATION SYSTEM
Linnaeus’ classification system
has seven levels.
Limitations:
It doesn’t account for molecular
evidence such as DNA
sequencing.
Linnaean system based only on
physical similarities.
38. MODERN CLASSIFICATION SYSTEM
Cladistics – classification based on
common ancestry.
Phylogeny – evolutionary history for a
group of species. Based from evidences
from living species, fossil records, and
molecular data.
Phylogenetic tree - a diagram that
depicts the lines of evolutionary descent
of different species, organisms, or genes
from a common ancestor.
41. ECOSYSTEM
A biological community of
interacting organisms
and their physical
environment.
It has two major
components: Abiotic and
Biotic components.
42. COMPONENTS OF ECOSYSTEM
BIOTIC COMPONENTS
Living components of an
ecosystem.
producers, consumers,
and decomposers
ABIOTIC COMPONENTS
The physical and/or the
chemical factors that act on the
living organisms at any part of
their life. Light, air, soil, and
nutrients.
43. SYMBIOTIC RELATIONSHIPS
MUTUALISM
when two species of
organisms benefit from
living in close association
with each other.
COMMENSALISM
a symbiotic relationship in
which one species benefit
and the other species is
not significantly affected.
PARASITISM
relationship between the
two living species in
which one organism is
benefitted at the
expense of the other.
45. FOOD CHAINS AND FOOD WEBS
A food chain is a series of steps in
which organisms transfer energy by
eating and being eaten.
Food chains can vary in length.
Composed of:
• Producers
• Primary Consumers
• Secondary Consumers
• Tertiary Consumers
• Apex Predator
• Decomposers
46. TROPHIC LEVELS
TROPHIC LEVEL
WHERE IT GETS
FOOD
EXAMPLES
1st Trophic Level:
Producer
Makes its own food Plants make food
2nd Trophic Level:
Primary Consumer
Consumes producers Mice eat plant seeds
3rd Trophic Level:
Secondary Consumer
Consumes primary
consumers
Snakes eat mice
4th Trophic Level:
Tertiary Consumer
Consumes secondary
consumers
Hawks eat snakes
47. FOOD CHAINS AND FOOD WEBS
Food Web - feeding relationships are
much more complicated than the
relationships described in a single,
simple chain because many animals
eat more than one kind of food.
Each path through a food web is a
food chain.
A food web, like the one shown, links
all of the food chains in an
ecosystem together.
48. ENERGY FLOW IN ECOSYSTEMS
Ecological Pyramids show the
relative amount pf energy or
matter contained within each
trophic level in a given food
chain or food web.
Types:
• Pyramid of energy
• Pyramid of biomass
• Pyramid of numbers
49. ENERGY FLOW IN ECOSYSTEMS
Ecological Pyramids show the
relative amount pf energy or
matter contained within each
trophic level in a given food
chain or food web.
Types:
• Pyramid of energy
• Pyramid of biomass
• Pyramid of numbers
50. PYRAMID OF ENERGY
Pyramids of energy show the relative amount of
energy available at each trophic level.
Organisms expend much of the energy they
acquire on life processes, such as respiration,
movement, growth, and reproduction.
Most of the remaining energy is released into the
environment as heat— a byproduct of these
activities.
51. PYRAMID OF ENERGY
On average, about
10 percent of the
energy available
within one trophic
level is transferred
to the next trophic
level.
RELATIVE DATING
Rocks, fossils, or geological events are given an order of occurrence.
It does not use specific numerical values.
Sedimentary rocks are formed from pre-existing rocks or pieces of once-living organisms.
These time spans include:
age (million of years)
epoch (tens of million years)
period (one hundred million years)
era (several hundred million years)
eon (half billion years or more)
The earliest living organisms were microscopic bacteria, which show up in the fossil record as early as 3.4 billion years ago.
The oldest known fossils, in fact, are cyanobacteria from Archaean rocks of western Australia, dated 3.5 billion years old.
Stromatolites are the oldest fossils on earth, dating back to more than three billion years ago.
In an oxygenated world, organisms could thrive in ways they could not earlier. Oxygen also changed the chemistry of the planet in significant ways. For example, iron can be carried in solution in a non-oxygenated environment.
In an oxygenated world, organisms could thrive in ways they could not earlier. Oxygen also changed the chemistry of the planet in significant ways. For example, iron can be carried in solution in a non-oxygenated environment.
Extinction occurs when the last individual organism of a species dies.
A mass extinction occurs when many species become extinct within a few million years or less.
Extinctions can occur when environments change.
The fossil record contains evidence of the appearance of many new species over time.
In an oxygenated world, organisms could thrive in ways they could not earlier. Oxygen also changed the chemistry of the planet in significant ways. For example, iron can be carried in solution in a non-oxygenated environment.
In an oxygenated world, organisms could thrive in ways they could not earlier. Oxygen also changed the chemistry of the planet in significant ways. For example, iron can be carried in solution in a non-oxygenated environment.
proportion of a specific allele in a population
proportion of a specific allele in a population
Inbreeding - mating between individuals of similar
genotypes, either by choice or due to environmental factors
such as location
Assortative mating- a type of non
random mating where mates are (sexually)
selected based on phenotypes
Positive assortative mating- selection for
the same phenotype
Negative assortative mating – selection for
the opposite phenotype
In an oxygenated world, organisms could thrive in ways they could not earlier. Oxygen also changed the chemistry of the planet in significant ways. For example, iron can be carried in solution in a non-oxygenated environment.
proportion of a specific allele in a population
Speciation occurs when a group within a species separates from other members of its species and develops its own unique characteristics.
proportion of a specific allele in a population
Selective breeding makes use of existing, naturally present gene variants in a species and the natural process of breeding.
This one plant was selectively bred over hundreds of years to create dozens of wildly different vegetables. By selecting and breeding plants with bigger leaves, or larger buds, the various cultivars were created.
This one plant was selectively bred over hundreds of years to create dozens of wildly different vegetables. By selecting and breeding plants with bigger leaves, or larger buds, the various cultivars were created.
HOMOLOGOUS STRUCTURES - are body parts of organisms that are similar in structure and position but different in function.
ANALOGOUS STRUCTURES - Body parts that perform a similar function but differ in structure. Organisms evolve to the environment in similar ways! Wings and fins are perfect examples!
Pharyngeal pouches develop in the early embryos of all vertebrates, including the air-breathing terrestrial reptiles, birds, and mammals. The number of pouches has been reduced in the course of evolution from six or more to four in tetrapods, and the posterior pouches may not actually break through.
Speciation occurs when a group within a species separates from other members of its species and develops its own unique characteristics.
Speciation occurs when a group within a species separates from other members of its species and develops its own unique characteristics.
Speciation occurs when a group within a species separates from other members of its species and develops its own unique characteristics.
Speciation occurs when a group within a species separates from other members of its species and develops its own unique characteristics.
Speciation occurs when a group within a species separates from other members of its species and develops its own unique characteristics.
Physical similarities are
not always the result of
close relationships.
Genetic similarities more
accurately show
evolutionary relationships.
Remember a phylogenetic tree shows evolutionary and genetic distance while a cladogram displays related characteristics.
CLADISTICS – HYPOTHETICAL, CAN EASILY MAKE YOUR OWN
PHYLOGENY - BASED ON MOLECULAR EVIDENCE OR DATA
Derived characters are traits shared in different degrees
by clade members.
basis of arranging species in cladogram
more closely related species share more derived characters
represented on cladogram as hash marks
THE CLOSER THE NODES, THE MORE GENETICALLY SIMILAR
Speciation occurs when a group within a species separates from other members of its species and develops its own unique characteristics.
Selective breeding makes use of existing, naturally present gene variants in a species and the natural process of breeding.
a close, long-term relationships of organisms between different species.
Parasite – benefitted
Host - harmed
Selective breeding makes use of existing, naturally present gene variants in a species and the natural process of breeding.
Physical similarities are
not always the result of
close relationships.
Genetic similarities more
accurately show
evolutionary relationships.
The feeding positions in a food chain or web are called trophic levels. The different trophic levels are defined in the Table below.
Physical similarities are
not always the result of
close relationships.
Genetic similarities more
accurately show
evolutionary relationships.
