W5-6-REVOLUTIONARY RELATIONSHIP.pptx

PRAYER
Father God,
Come be with us today
Fill our hearts with joy
Fill our minds with learning
Fill our classroom with peace
Fill our lesson with fun
Fill our friendships with kindness
Fill our school with love
Amen.

CLASSROOM RULES
1. Have RESPECT so you earn it
too.
2. Come to class on time.
3. Be ready to learn.
4. Listen and follow
instructions.
5. Raise your hand to speak.
6. Believe yourself.
7. Work hard and have fun!

After going through this lesson, you should be able to:
1. Identify the different classifications of organisms.
2. Classify organisms into a hierarchy based on their
unique/ distinctive characteristics.
3. Describe a dichotomous key and its role in
hierarchical classification.
4. Appreciate the work of Linnaeus regarding
identifying the unique/ distinctive characteristics of a
specific taxon relative to other taxation.
LEARNING OBJECTIVES:

Direction: Read and analyze the following questions, encircle the letter of the correct answer.
1. What do you call the process of grouping or ordering plants based on structural similarities or evolutionary
relationships?
a. classification b. collection c. identification d. preservation
2. In biological levels of classification, what is considered as the largest unit?
a. class b. family c. kingdom d. order
3. Who is the father of taxonomy?
a. Anton Van Leuwenhooke b. Carolous Linnaeus c. Charles Darwin d. Robert Hooke
4. What do you call the type of classification that is based on similarity of structures?
a. natural classification b. artificial classification c. superficial classification d. phylogenetic
classification
5. Plants may be classified as vascular and non-vascular. Which of the following are vascular bundles?
a. endodermis and pericycle c. sclereids and scherenchyma
b. parenchyma and collenchyma d. xylem and phloem
WHAT I KNOW?

6. Animals show characteristics that are common to them. Which of the following is NOT a characteristic ability
of animals? a, ability to breathe c. ability to produce their own food
b. ability to digest food d. ability to move from one place to another
7. In the binomial system of classification, organisms are given two names. What is it composed of?
a. family and genus name c. order and genus name
b. genus and species name d. local and international name
8. Jellyfishes are noted for their powerful tentacles. What are their tentacles for?
a. for excretion c. for reproduction
b. for digestion d. for capturing food and defense
9. Warm-blooded animals can adapt to changes in environmental temperature. Which of the following animals is
NOT warm-blooded?
a. cheetah b. crocodile c. leopard d. man
10. Mammals are vertebrates with mammary glands. These glands supply the young
a. hormones b. milk c. salts d. water

Arrange Me Now!
Dirrection: Arrange the following jumbled letters and identify it. Write
your answers on the space provided.
WHAT’S NEW?
JUMBLED WORD WHAT AM I?
G O Y H O O L M
S E I C E P S
A M S T Y S C I T E
L O V E N O I T U
D E N C E E V I

WHAT’S IS IT? Systematics Based on Evolutionary
Relationships: Taxonomy
It was devised by Carl Linnaeus
(1707-1778).
In 1981, a category higher than a
kingdom, called domain, was proposed
by Carl Woese.
It is a hierarchical system since organisms
are grouped into ever more inclusive
categories from species up to kingdom.

W5-6-REVOLUTIONARY RELATIONSHIP.pptx

LINNAEAN TAXONOMY
The Linnaean taxonomy which is hierarchical in nature is the most employed
system nowadays.
The scientific name of a species is a “binomial name”, which includes two parts:
the genus and the species epithet. Nomenclature refers to the practice of assigning
scientific names. Binomial comes from the words “bi” meaning “two” and “nomen”
meaning “name”. A species name consists of two parts: the genus or generic name and
the specific epithet. The first letter of the genus is always capitalized (e.g. Canis) while
the specific epithet is not capitalized (e. g. familiaris). One can distinguish a species
name from the way it is written. Species name can be in bold letters or underlined or
italicized.

Example:
Dog
Scientific Name: Canis familiaries
Genus Name: Canis
Species Ephitet: familiaries

Lines of evidence to infer evolutionary relationships:
1.Fossil evidence- The fossil record provides
snapshots of the past that,when
assembles,illustrate a panorama of evolutionary
change over the past 4 billion years. The picture
may be smudged in places and have bits missing,
but fossil evidence clearly shows that life is old
and has changed over time.
2.Homologies - Similar characters due to
relatedness are known as homologies. Homologies
can be revealed by comparing the anatomies of
different living things, looking at cellular
similarities and differences, studying
embryological development, and studying
vestigial structures within individual organisms.

3.Developmental biology - Studying the
embryological development of living things
provides clues to the evolution of present -
day organisms. During some stages of
development, organisms exhibit ancestral
features in whole or incomplete form.
4.Biogeography - the geographic
distribution of species in time and space as
influenced by many factors, including
Continental Drift and long -distance
dispersal.
5.Molecular clocks help track evolutionary
time - Method used to estimate the amount
of time needed for a certain amount of
evolutionary change.

Classification is linked to
PHYLOGENY
Biologists use phylogenetic trees for many purposes, including:
I. Testing hypotheses about evolution
II. Learning about the characteristics of extinct species and ancestral lineages
III. Classifying organisms
The connection between classification and phylogeny is that hierarchical
classification is reflected in the progressively finer branching of phylogenetic trees. The
branching patterns in some cases match the hierarchical classification of groups nested
within more inclusive groups. In other situations, however, certain similarities among
organisms may lead taxonomists to place a species within a group of organisms (for
example genus or family) other than the group to which it is closely related. If
systematists conclude that such mistake has occurred, the organism may be reclassified
(that is placed in a different genus or family) to accurately reflect its evolutionary history.

Given the philosophical and scientific definitions of species, the
simplest way to explain that for one species to become two (incipient
species) is that separate populations of the same species must become re
productively isolated. For reproductive isolation to evolve, some change must
occur in one or both lineages in ecology, behavior, physiology, biochemistry,
or genetic system that will make them reproductively incompatible (De
Queiroz,2005). The process on how one lineage becomes incompatible with its
closest relative lineage is the key question of how new species are formed.
MODES OF SPECIATION

1.Allopatric speciation
. Is the evolution of reproductive barriers between
populations that are geographically separated.
Speciation occurs because a given group has been
separated from the parent group usually because of the
geographical event (i.e.,mountain building,
land,fragmentation etc.) as time goes by. The isolated
population then undergo genotypic and/phenotype
diverse as: (a) they become exposed to dissimilar
selective pressures;(b) undergo genetic drift
independently; or(c)different mutation arise in the
two populations (Hoskin et al,2005)).When the
populations come back into contact, they have evolved
such that they are no longer capable of exchanging
genes.

a.Peripatric speciation.
Involves new species that developed from reproductive isolation in small
marginal population of a species that are prevented from exchanging genes
with the main population. It is generally hypothesized that founder
populations, because they are small, have reduced genetic variation and
low fitness due to genetic drift. Genetic drift increases the frequency of
alleles that were documented to be rare in the ancestral
population.Selection of new combinations of alleles that are compatible
withe newly fixed alleles may occur and allow increased fitness in the new
conditions. This results reorganization of the genome that makes it
incompatible with the ancestral population (Templeton,1980). A famous
case study that explains this mode of speciation was the Australian bird
Petroica multi color.
Two Types of Allopatric
Speciation:

B.Parapatric speciation.
Involves the origin of new species over theformer range of the ancestral
species. The population can only divergeif there is relatively strong selection
cross the geographic range of thespecies. A stable hybrid zone may result if
there is moderate selectionagainst the hybrids. When a strong selection
against the hybrid occurs,complete divergence can occur similar to
reinforcement of reproductiveisolation in formerly allopatric populations. In
the case of parapatricspeciation, population of plants on contaminated soils is
one example.Hybrid are formed in an environment with contaminated soils
that areunfit in either environment. Selection against hybrids has resulted
indivergence in floweringtime in adjascent popultions and selection forself-
pollination in the population on the contaminated soil (Bank
etal.,2012) A good example is Plantago major, a common European plant.

2.Sympatric speciation
. Refers to the formation of two or more
descendant species from a single ancestral
species all occupying the same geographic
location. Habitat change and difference
inreproductive cycle is a strong disruptive
selection that may result indivergent
phenotypes. This produces hybrids that are
unfit for theenvironment for which the
parental types are well suited. A
commonexample of sympatric speciation is
found in insects that becomedependent on
different host plant in the same area.

At present, the following nomenclature codes govern the naming of
species, as follows:
• Algae, Fungi, and Plants – International Code of Nomenclature
for algae, fungi and plants
(ICN)
• Animals – International Code of Zoological Nomenclature (ICZN)
• Bacteria – International Code of Nomenclature of Bacteria (ICNB)
• Cultivated Plants – International Code of Nomenclature for
Cultivated Plants (ICNCP)
• Viruses – International Committee on Taxonomy of Viruses
(ICTV)

Some of the major rules in nomenclature, as guided by ICBN and ICZN, are the
following:
1. Names should be written in Latin.
2. The scientific name of an organism is always written with the genus
capitalized and the species epithet in lower case letters.
3. Because the words are Latinized, they should always be italicized
4. When scientific names are written by hand, each separate word should be
underlined.
5. The first name to be validly and effectively published gets the priority. This
rule has caused numerousname changes, particularly on fossil organisms.
6. All taxa must have an author when described. For example, Homo sapiens L.,
the Lstands for Linneaus who first successfully described and named the
organism.

DICHOTOMOUS KEY AS A TOOL IN
IDENTIFICATION
A dichotomous key is a tool that helps identify unknown
organisms to some taxonomic level (e.g.,species, genus,
family, etc.). The key is constructed in such a way that a
series of choices is made that leads the user to the correct
identity of a sample organism. "Dichotomous" means,
"divided into twoparts." Therefore, a dichotomous key
always offers two choices for each step, each of which
describes key characteristics of a particular organism or
group of organisms

Sample mnemonics:
• Kings Play Chess On Fine Glass Sets
• Kings Play Chess On Finely Green
Spaces
• Keep Pond Clean Or Froggy Gets Sick
• Kings Play Chess On Fine Grained
Sand
• King Philip Came Over For Green
Soup
• Kindly Put Candy Out For Good
Students

The Cladistic System
Cladistics or Phylogenetic Systematics is a method that
group organisms based on their shared derived characters.
It is said that only shared derived characters can provide
information on the phylogeny of the organism. This is an
important work published in 1966 by Willi Hennig. The
groupings mainly focus on taxa that share many derived
characters as opposed to those that do not have shared
derived characters.

Relationships are represented as a branching
hierarchical tree called a cladogram. The cladogram is
constructed such that the number of changes from one
character state to the next are minimized. In the cladistic
system, organisms are classified exclusively on the basis of
how recent are the descendants from their common
ancestor. Therefore, always remember that the
synapomorphies are the main bases for the determination of
taxonomic/phylogenetic relationships. The presence of many
shared derived characters among taxa is considered strong
evidence of their common descent. Differences in the degree
of rate of change among branches of organisms are i
rrelevant to their classification.

Reconstructing Phylogenies
1. Primitive vs. Derived Characters
Species found at present evolved from previously existing
species that we call as ancestral species. Any character that shows
little or no change from ancestral trait is said to be primitive and
those that undergo modification in terms of appearance and/or
function in relation to its ancestral trait is said to be derived
character. A primitive character is known as plesiomorphy; a
shared primitive character between two or more taxa is
symplesiomorphy; a derived character is apomorphy; a shared
derived character between two or more taxa is known as a
synapomorphy.

2. Homologous vs. Analogous Characters
If the similarity between two characters in two separate taxa
is attributable to their presence in a common ancestor, then these
two characters are said to be homologous. For example, the
forelimb bones of all tetrapod (four-legged) vertebrates are
homologous to one another because they all evolved from the
same bones in a common tetrapod ancestor. When two species
have a similar characteristic because of convergent evolution, the
feature is called an analogous feature. For example, a shark and a
dolphin both share a fusiform shape that is well adapted for rapid
swimming. However, while the shark’s body evolved from a
fishlike ancestor with a somewhat fusiform shape, the dolphin’s
fishlike form is secondarily derived from that of a terrestrial, four
legged mammalian ancestor.

3.Symplesiomorphies vs. Synapomorphies
All living things share evolutionary history, however distantly, each taxon shares certain very ancient
(i.e.,primitive, or plesiomorphic) characters with other taxa. Shared primitive characters cannot be used to
separate members of different taxa since everyone has them. However, more recently evolved (i.e., derived, or
apomorphic) characters can set one taxon apart from another. Synapomorphies inherited from a common
ancestor can inform the systematist about relative recency of common descent. The more synapomorphies two
taxa have in common, the more recently they evolved from a common ancestor (Krempels and lee,2013).
For examples, the hand of the first invertebrates to live on land had five digits. Many living terrestrial
vertebrates (such human, turtles, crocodiles, and frogs) also have five digits because they inherited from this
common ancestor. This feature is then homologous in all of these species. In contrast, horses, zebras, and
donkeys have just single digit with hoof. This simply means that humans are more closely related to horses,
zebras, and donkeys even they have a homology in common with turtles, crocodiles, and frogs. The five-digit
condition is primitive state (symplesiomorphic) for the number of digits. This was then modified and reduced to
just one digit in the common ancestor of horses,donkeys, and zebras. The modified derived state
(synpomorphic) does tell usthat horses, zebras, and donkeys share a very recent common ancestor, but the
primitive form is not an evidence that the species are particularly closely related (Krempels and Lee,2013)

Directions: Identify what is being described in each number. Write your answer in a clean sheet of paper.
1. He devised the present-day taxonomic system.
2. A system of organizing groups into ranks according to status; putting groups at various levels.
3. The theory and practice of classifying organisms.
4. A yardstick for measuring the absolute time of evolutionary change based on the observation that some
genes and other regions of genomes appear to evolve at constant rates.
5. The evolutionary history of a species or group of species
6. The study of the kinds and diversity of organisms and of all relationships among them.
7. Similarity due to shared ancestry.
8. Studying the embryological development of living things provides clues to the evolution of present-day
organisms.
9. Refers to the practice of assigning scientific names.
10. Is a tool that helps identify unknown organisms to some taxonomic level (e.g., species, genus, family, etc.)
WHAT’S MORE?

Directions: Construct your own mnemonics on the hierarchy
of taxonomy. (example: Kindly Put Candy Out For Good
Students) After that, make a 3 sentence explanation about
your mnemonics. Make it as comprehensive as you can.
(10 points)
WHAT I CAN DO? CONSTRUCT YOUR OWN!

Direction: Read and analyze the following questions, encircle the letter of the correct answer.
1. Which phylogenetic model proposes that all the three domains of life evolved from a pool of primitive
prokaryotes?
a. tree of life b. web of life c. ring of life d. network model
2. Which of the following situation is NOT a part of a taxonomist role?
a. Assigning the scientific name to various mosses surveyed in a pristine forest.
b. Constructing a comprehensive compendium of birds in a reserved national park.
c. Provide an in-depth annotation about the morphology of parasitic insects
d. Explain the relatedness of endemic plants found in two different populations
e. Identify an unknown flowering plant found in a herbarium.
3. Which of the following statements is incorrect about the rules in biological nomenclature?
a. Order is a higher rank than family
b. Linnean nomenclature is composed of genus and specific epithet
c. A taxon is composed of a name, rank and content
d. It is not a standard rule for all organisms to have a latinized scientific name
e. When writing a scientific name of plants by hand in paper, it must be always italicized.
ASSESSMENT

4. Which of the following best explains the morphological species concept?
a. Sexual reproduction among only similar kinds of species is likely to occur.
b. Different clones with variations in its genetic composition is considered a
separate species.
c. Speciation genes among species caused variation in individuals.
d. Mating among different breeds is impossible.
e. A clear difference in appearance makes one a separate species.
5. Which of the following terms is related to cladistics.
a. branching tree
b. synapomorphy characters
c. primitive domain
d. paraphyly

True or False
Directions: Read the following statement. Write T if the statement is TRUE and
F if the statement is FALSE. Write your answer on the space provided before
each number.
_______ 1. Constructing a phylogenetic tree is one way to visualize
evolutionary relatedness.
_______ 2. Phylogenetic systematics emphasize descent and common
ancestry in order to determine the evolutionary history of groups of
organisms as a determining factor in classification.
_______ 3. Phylogeny is based on the phylogenetic theories that all living
organisms share a common ancestry.
_______ 4. The main goal of phylogenetic tree is to create a diagram that
represents evolutionary relationships among organisms.
_______ 5. Shared derived characters can reveal all the degrees of
relationships between different living and nonliving organisms.

W5-6-REVOLUTIONARY RELATIONSHIP.pptx

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