Gen Bio reviewer
Module 7: Mechanism of Evolutionary change
Evolution (Change over time)
- Any change in the characteristics of organism or
population
- How the organism now descends from the ancient
ones.
Biodiversity (Biological diversity)
- Number and kinds of life on earth at all levels at a
particular time.
Theory
- Idea presented that can be tur but is not proven or
know to be true
- Explanation of natural phenomena
Natural selection
- adaptation of an organism to its environment by
means of selectively reproducing changes in its
genotype or genetic constitution.
Fitness
- ability to survive and reproduce in a specific
environment
Principle of descent with modification
- Species change over time, giving rise to new species
and that all species share same ancestors
Principle of common descent
- all living things from earth share common ancestors,
all life form are genetically and phylogenetically related.
TYPES OF NATURAL SELECTION
Directional selection
- single phenomena is favored, causing all allele
frequency to continuously shift in one direction.
- change in environment change the observable
phenotype.
Stabilizing selection
- population stabilizes on a particular trait value and
genetic diversity decreases.
- intermediate phenotypes are more likely to survive in
the environment
Disruptive/Diversifying selection
- extreme phenotypes are more likely to adapt to the
environment.
Artificial selection
(Proposed by Charles Robert Darwin)
- is an evolutionary process in which humans
consciously select for or against particular features in
organisms
Nonrandom mating
- contributes to the population change from one
generation to the next. Described as the selected
probability of mating with another individual in the
population.
Inbreeding- Mate with their close relatives than
distant relatives
Outbreeding/Assortative mating- select distant
relative than close relative as their partners
Genetic drift
- unpredictable changes in allele frequencies due to
small population sizes.
Population bottleneck
- Significant reduction in the size of a population that
can occur due to a variety of events that results in a
drastic reduction of the total genetic diversity of the
original population
Founder effect
- a loss of genetic variation because of the migration of
a small subgroup in a population.
Mutation
- Change in the structure of a gene caused by
alterations in the DNA sequence of an organism
TYPES OF MUTATIONS
Substitution (one letter)
- occurs when the genetic codon has one altered
nitrogenous base.
Insertion (addition of one pair)
- characterized by the addition of an extra set of base
pairs to the genetic material.
Deletion (one pair missing)
- set of base pairs in the genetic material is omitted
Neutral mutation
- affects the organism’s phenotype but has no impact on
its survival or reproduction
Beneficial mutation
- affects the phenotype of organisms, resulting in an
increase in their chances of survival or reproduction
Recombination
- Simply rearrangement of genes
Gene flow (Migration)
- there is a transfer of genes from the gene pool of one
population to another
Emigration- Leaves their habitat
Immigration- Enter another habitat ang live in it
Module 8: Theories of evolution and the evidences
supporting them
John Ray (1627-1705)
- Established the modern concept of species, noting that
members of one species do not interbreed with
members of another species.
- first used the term species as the basic unit of
taxonomy
- studied fossils and recognized them as remnants of
organisms that were once alive.
CARL LINNAEUS OR CAROLUS LINNAEUS (1707–1778)
- developed the modern taxonomic system that is still
used today.
GEORGES LOUIS LECLERC, COMTE DE BUFFON (1707–
1788)
- wrote a 36-volume Histoire Naturelle (Natural History)
series.
- contributed to the debate on the age of Earth,
suggesting that our planet had initially formed in a
molten state and that its gradual cooling must have
taken far longer than 70 000 years
- considered the role of vestigial organs, creating a
possibility of species descending from earlier organisms
ERASMUS DARWIN (1731–1802)
-Charles Darwin’s grandfather.
- aware that the modern organisms are different from
the fossils scientists have collected.
- believed that the offspring inherited features from
their parents, and that the organisms today descended
from a common ancestor.
GEORGES CUVIER (1769–1832)
- studied and wrote books on comparative anatomy,
which were extremely useful in interpreting the remains
of fossils.
- classified animals based on their body plans. This
classification eventually became important in analyzing
relationships among organisms.
- studies about fossils contributed and gave rise to the
science of paleontology.
- recognized that particular groups of fossil organisms
were associated with certain rock strata.
JEAN-BAPTISTE LAMARCK (1744-1829)
- proposed the theory of use and disuse, which stated
that organisms develop their traits due to the frequent
use of such.
- proposed that those traits may be passed on to their
offspring
JAMES HUTTON (1726–1797)
- made a significant contribution regarding the
understanding of the geological processes that shaped
Earth.
- recognized Earth is extremely old (more than millions
of years), and no need for global catastrophes to shape
the surface of Earth.
- was the proponent of uniformitarianism, which states
that the present geological features of Earth are the
results of gradual processes such as erosion and
sedimentation.
- It was through Hutton that Charles Darwin was able to
adapt the principles of gradual change to his model of
how species evolved
CHARLES LYELL (1797–1875)
- shaping of Earth’s surface as a result of gradual, longterm natural changes.
- collected many pieces of evidence to support the
principle of uniformitarianism and wrote about them in
his book Principles of Geology, which was also
influential to the creation of Charles Darwin’s theory
CHARLES ROBERT DARWIN (1809–1882)
- came up with the idea that the best-adapted
organisms are those that can survive to breed and pass
on their traits to their offspring.
- One of his highlighted contributions was the
development of his theory of evolution by natural
selection as a coherent explanation for the form and
distribution of species in different locations.
ALFRED RUSSEL WALLACE (1823–1913)
- made an independent study on the origin of
organisms, Wallace arrived at the same conclusion as
Darwin’s: that organisms with favorable traits are those
that carry on to the next generation. Thus, Wallace had
contributed to some of the postulates of Darwin’s
theory of evolution.
CHARLES DARWIN AND HIS THEORY OF EVOLUTION
- Contributed significant ideas on our current
understanding of evolution. He was born in England on
12 February 1809. In 1831, Darwin went aboard the
H.M.S. Beagle in its voyage around the world.
JEAN-BAPTISTE LAMARCK
- French naturalist and the early proponent of the idea
of evolution, provided an explanation on how life
evolved based on the fossils that he studied, calling it
the theory of use and disuse.
Theory of use and disuse- organisms could alter
the size, shape, or structure of particular body parts or
organs by continuously using them in new ways.
THEORY OF INHERITANCE OF ACQUIRED
CHARACTERISTICS (PROVEN TO BE INCORRECT)
- organisms inherited their traits from their parents, and
that they may also pass them on to the next generation
of offspring
EVIDENCE OF EVOLUTION
Biogeography
- study of the distribution of plants and animals on
Earth.
Fossil record
- provide strong evidence of the history of life on Earth.
Fossil
- contains preserved remains or evidence of ancient
organisms.
Homology
- found by studying and comparing certain body parts of
different animals called homologous structures.
Embryology
- the similarities in the early development of various
organisms
DNA/Protein Sequences
- important for identifying the evolution of organisms
on Earth
DNA sequencing
- is the most advanced tool or evidence for evolution.
Module 9.1: Different Kingdoms of Classification
Two Kingdoms (Plantae and Animalia)
-kingdom system of classification was first established
by Aristotle, in which he divided organisms into plants
and animals based on his observations.
- Divided the big groups into subgroups, plant based on
size and animals based on habitat (air, water, and land)
Three Kingdoms (Plantae, Animalia, and Protista)
- use of microscopes also helped scientists such as the
German naturalist Ernst Haeckel to introduce Kingdom
Protista
- grouped the microscopic, unicellular organisms that
have intermediate characteristics of plants and animals
under Kingdom Protista.
Fourth Kingdom (Plantae, Animalia, Protista, and
Monera)
- developments in microscopy led the French marine
biologist Edouard Chatton to introduce the term
prokaryotes and eukaryotes.
- prokaryotes without nuclei in their cells and
eukaryotes with nuclei.
- From this establishment, Herbert Copeland, an
American biologist, proposed the four-kingdom
classification scheme. He grouped all prokaryotes under
Kingdom Monera. (Eukaryotes= animalia, protista, and
plantae)
Five Kingdom (Plantae, Animalia, Protista, Monera,
and Fungi)
- In 1969, Robert Whittaker, an American ecologist,
introduced Kingdom Fungi, which includes stationary
organisms that are not photosynthetic.
- based his scheme on the similarities and differences of
body forms, the manner of obtaining nutrients, cell
structure, and patterns of development
Six Kingdoms (Monera divided into 2 Eubacteria and
Archaebacteria)
- In 1970s, a group of scientists led by Carl Woese
proposed that Kingdom Monera can be further divided
into Kingdom Eubacteria and Kingdom Archaebacteria
- Archaebacteria have a distinct plasma membrane and
cell wall it also have genetic materials that resembled
humans and eukaryotes more than that of other
prokaryotes.
Eight kingdoms (Protista is divided into 3 Archezoa,
Protozoa, Chromista)
- Kingdom Protista is subdivided into Kingdom Archezoa,
Kingdom Protozoa, and Kingdom Chromista. However,
this proposed classification scheme has yet to gain
widespread universal acceptance.
Three Domain System
- Carl Woese to discover that Kingdom Archaebacteria
and Kingdom Eubacteria are genetically distinct from
each other.
- This enabled him to establish the three-domain system
of classification, which replaced the two empire system:
Kingdom Eubacteria is now classified under Domain
Bacteria; Kingdom Archaebacteria is now classified
under Domain Archaea; and Kingdom Eukaryota
became Domain Eukarya
Domain Bacteria (found soil, atmosphere, and
intestine)
- are the organisms under Kingdom Eubacteria. They are
unicellular, prokaryotic organisms. They have thick and
rigid cell walls composed of a substance known as
peptidoglycan.
Domain Archaea (volcanic hot spring, brine pools,
black organic mud, and dead sea)
- include Kingdom Archaebacteria
- all of its members are unicellular and prokaryotic. They
have cell walls that lack peptidoglycan, and their cell
membranes have lipids that are not found in other
organisms.
Domain Eukarya
- derives its name from the eukaryotic cells of the
organisms included in this domain. Being eukaryotic is
the main feature that unites Kingdoms Protista, Fungi,
Plantae, and Animalia into this domain
DOMAIN PROTISTA
- Protists are the most biologically diverse. There are
different groups of protists that cannot be classified as
plants, animals, or fungi; thus they are called plantlike,
animal-like, and fungal like protists. Most protists are
unicellular, but some are colonial or multicellular
DOMAIN FUNGI
- Fungi cannot make their own food. They can only
absorb their food from their surroundings into their
bodies. In doing so, they secrete digestive enzymes into
their food source so they can easily absorb the
necessary nutrients.
DOMAIN PLANTAE
- Plantae include all plants. They are multicellular
organisms that create their own food by
photosynthesis. They cannot move from one place to
another. They have cell walls composed of cellulose.
They are very diverse in size, ranging from the small
mosses to the large and tall pine trees
DOMAIN ANIMALIA
-Kingdom Animalia are multicellular and heterotrophic.
Animal cells do not have cell walls. Most of them can
move, although a few are nonmotile in their adult forms
such as sponges. They have various ways of obtaining
their nutrition. Many animal species exist in nearly
every part of the planet.
Module 9.2: Systematics based on Evolutionary
relationships
History of Taxonomy
Taxonomy
- Ancient Greek word “taxis”= arrangement and
“nomia” or “nomos”= method
- a science that deals with the classification of
organisms based on shared characteristics
SCIENTISTS CONTRIBUTION IN TAXONOMY
Aristotle (384-322 BC)
- first Greek philosopher to classify organism
- Classified invertebrates and vertebrates as animals
without blood and with blood, respectively
- divided animals based on how they give birth (e.g., live
bearing and egg-bearing), and grouped invertebrates
into insects, crustaceans, and mollusks.
Phylogeny
- Classification systems used by modern taxonomists are
based on many evolutionary clues
- natural system of classification based on the
evolutionary history or genealogy shared by a group of
organisms
- Come from internal and external anatomy organism
also include patterns of embryological development
and molecular biochemistry
Phylogenetic trees
- show the evolutionary relationships of organisms
based on the best available pieces of evidence.
-similar to the family tree used to trace the lineage of a
person to his or her set of ancestors.
-information gathered on an organism and its relatives
affect the accuracy of the phylogenetic tree.
Cladistics
- Best way to draw phylogenetic trees
- analytical method of refining the evolutionary
classification of organisms
- It involves identifying shared derived characteristics.
- These characteristics are traits that evolved in only one
species and are present only in its descendants
Cladogram
- used to show shared characteristics
CLASSIFYING ORGANISM
Taxonomy
- classifying organisms into groups that have biological
meaning
Scientific name
- uses Latin words, the language commonly used by
18th-century scientists
- the “genus” (always capitalized) and the “species”
epithet (written in italics)
Common names
- use locally and vary by region or country
Binomial names
- Consist of genus name and specific epithet
Binomial nomenclature
- two word naming system
- each species is assigned a two-part scientific name,
wherein the first letter of the first word is capitalized
and the second word is set in lowercase
The modern taxonomic system was developed by the
Swedish botanist Carolus Linnaeus He used simple
physical characteristics of organism to identify and
differentiate species based on their genetics
He developed a hierarchy of groups for taxonomy. To
distinguish different level of similarity, each classifying
groups called “Taxon”.
Kingdom
- is the largest and most inclusive among the Linnaean
taxa
Phylum
- one of the major taxa used in classifying organisms.
This taxon includes many different organisms that share
important characteristics, which include their body
plans.
Class
- broadly includes the major organisms that are distinct
from other organisms internally and externally.
Order
- composed of a number of similar families
Family
- includes one or more genera that share a common
phylogenetic origin.
Genus
- taxon that includes one or more species with common
phylogenetic traits
Species
- basic unit of classification
- used as the specific epithet in the scientific name.