Introduction to Life Science and The Theories on the Origin of LifeSimple ABbieC
I. Introduction to Life Science
II. The Concept of Life
III. Characteristics of Life
IV. Theories on the Origin of Life
V. Unifying Themes in the Study of Life
• THEMES OF LIFE:
o BIOLOGICAL SYSTEMS
o THE CELLULAR BASIS OF LIFE
o STRUCTURE AND FUNCTION
o REPRODUCTION AND INHERITANCE
o ENVIRONMENTAL INTERACTIONS
o ENERGY AND LIFE
o REGULATION
o EVOLUTION AND DIVERSITY
o SCIENTIFIC INQUIRY
o SCIENCE, TECHNOLOGY AND SOCIETY
Lesson 1 In the Beginning (Big Bang Theory and the Formation of Light Elements)Simple ABbieC
Content: How the Elements Found in the Universe were Formed
Content Standard:
The learners demonstrate an understanding of:
• the formation of the elements during the Big Bang and during stellar evolution
Learning Competency
The learners:
• give evidence for and explain the formation of the light elements in the Big Bang theory (S11/12PS-IIIa-1)
Summary
• The big bang theory explains how the elements were initially formed the formation of different elements involved many nuclear reactions, including fusion fission and radioactive decay
• There are three cosmic stages through which specific groups of elements were formed.
(1) The big bang nucleosynthesis formed the light elements(H, He, and Li).
(2) Stellar formation and evolution formed the elements heavier than Be to Fe.
(3) Stellar explosion , or supernova, formed the elements heavier than Fe.
• Atoms are the smallest unit of matter that have all the properties of an element. They composed of smaller subatomic particles as protons, neutrons, and electrons. Protons have positive charge, neutrons are electrically neutral; and electrons have a negative charge.
• The nucleus, which takes the central region of an atom, is comprised of protons and neutrons, electrons move around the nucleus.
• The atomic number (Z) indicates the number of protons in an atom. In a neutral atom, number of protons is equal to the number of electrons. The atomic mass (A) is equal to the sum of the number of protons and neutrons.
• Isotopes refer to atoms with the same atomic number but different atomic masses.
• Ions, which are positively or negatively charged particles, have the same number of protons in different number of electrons.
Introduction to Life Science and The Theories on the Origin of LifeSimple ABbieC
I. Introduction to Life Science
II. The Concept of Life
III. Characteristics of Life
IV. Theories on the Origin of Life
V. Unifying Themes in the Study of Life
• THEMES OF LIFE:
o BIOLOGICAL SYSTEMS
o THE CELLULAR BASIS OF LIFE
o STRUCTURE AND FUNCTION
o REPRODUCTION AND INHERITANCE
o ENVIRONMENTAL INTERACTIONS
o ENERGY AND LIFE
o REGULATION
o EVOLUTION AND DIVERSITY
o SCIENTIFIC INQUIRY
o SCIENCE, TECHNOLOGY AND SOCIETY
Lesson 1 In the Beginning (Big Bang Theory and the Formation of Light Elements)Simple ABbieC
Content: How the Elements Found in the Universe were Formed
Content Standard:
The learners demonstrate an understanding of:
• the formation of the elements during the Big Bang and during stellar evolution
Learning Competency
The learners:
• give evidence for and explain the formation of the light elements in the Big Bang theory (S11/12PS-IIIa-1)
Summary
• The big bang theory explains how the elements were initially formed the formation of different elements involved many nuclear reactions, including fusion fission and radioactive decay
• There are three cosmic stages through which specific groups of elements were formed.
(1) The big bang nucleosynthesis formed the light elements(H, He, and Li).
(2) Stellar formation and evolution formed the elements heavier than Be to Fe.
(3) Stellar explosion , or supernova, formed the elements heavier than Fe.
• Atoms are the smallest unit of matter that have all the properties of an element. They composed of smaller subatomic particles as protons, neutrons, and electrons. Protons have positive charge, neutrons are electrically neutral; and electrons have a negative charge.
• The nucleus, which takes the central region of an atom, is comprised of protons and neutrons, electrons move around the nucleus.
• The atomic number (Z) indicates the number of protons in an atom. In a neutral atom, number of protons is equal to the number of electrons. The atomic mass (A) is equal to the sum of the number of protons and neutrons.
• Isotopes refer to atoms with the same atomic number but different atomic masses.
• Ions, which are positively or negatively charged particles, have the same number of protons in different number of electrons.
Earth and Life Sciences for Senior High School by Duyanen and Andaya pages 176-179
My fun and colorful grade 11 report on Life Sciences 2nd semester of A.Y. 2016-2017 under Ms. Lagmay
FEATURING THE SUMMARY OF SCIENCE 10 UNIT 3 MODULE 3
GEOLOGIC TIME SCALE
THEORIES OF EVOLUTION
BIODIVERSITY
FOSSILS
RELATIVE DATING METHOD
RADIOMETRIC DATING METHOD
HOMOLOGOUS
ANALOGOUS
THEORY OF NATURAL SELECTION
TOPICS:
• THE CONCEPT OF LIFE
• WHAT QUALIFIES SOMETHING AS “LIVING”?
o MOVEMENT
o SENSITIVITY
o DEATH
o COMPLEXITY
• THEORIES ON THE ORIGIN OF LIFE
o EXTRATERRESTRIAL ORIGIN
o PANSPERMIA
o DIVINE CREATION
o ORIGIN FROM NONLIVING MATTER (PHYSICO-CHEMICAL THEORY)
• FORMATION OF THE FIRST CELL
• EARLY LIFE FORMS
Origin Of Life: Are we here by chance? Theories on origin of life, Scientific and Special Creation. Different Theories of life's origin including Aristotle's theory, Pasteur, Redi and Leuwenhook experiment, Abiogenesis, etc.
Fossils and its evolutionary significance.
Touring the Universe (An Introduction to Formation of the Universe)
I hope this lesson can shed light to SHS Grade 11 Science Teachers. My appeal to those who will download this ppt. please email me at marileahmendina08@gmail.com for my own references. I would be glad to hear from you.
Lesson 2 We Are All Made of Star Stuff (Formation of the Heavy Elements)Simple ABbieC
Content: How the elements found in the universe were formed
Content Standard:
At the end of the lesson, you will be able to demonstrate an understanding of:
the formation of the elements during the Big Bang and during stellar evolution
the distribution of the chemical elements and the isotopes in the universe
Learning Competencies:
At the end of the lesson,
Give evidence for and describe the formation of heavier elements during star formation and evolution (S11/12PS-IIIa-2)
Write the nuclear fusion reactions that take place in stars that lead to the formation of new elements (S11/12PS-IIIa-3)
Describe how elements heavier than iron are formed (S11/12PSIIIa-b-4))
Earth and Life Sciences for Senior High School by Duyanen and Andaya pages 176-179
My fun and colorful grade 11 report on Life Sciences 2nd semester of A.Y. 2016-2017 under Ms. Lagmay
FEATURING THE SUMMARY OF SCIENCE 10 UNIT 3 MODULE 3
GEOLOGIC TIME SCALE
THEORIES OF EVOLUTION
BIODIVERSITY
FOSSILS
RELATIVE DATING METHOD
RADIOMETRIC DATING METHOD
HOMOLOGOUS
ANALOGOUS
THEORY OF NATURAL SELECTION
TOPICS:
• THE CONCEPT OF LIFE
• WHAT QUALIFIES SOMETHING AS “LIVING”?
o MOVEMENT
o SENSITIVITY
o DEATH
o COMPLEXITY
• THEORIES ON THE ORIGIN OF LIFE
o EXTRATERRESTRIAL ORIGIN
o PANSPERMIA
o DIVINE CREATION
o ORIGIN FROM NONLIVING MATTER (PHYSICO-CHEMICAL THEORY)
• FORMATION OF THE FIRST CELL
• EARLY LIFE FORMS
Origin Of Life: Are we here by chance? Theories on origin of life, Scientific and Special Creation. Different Theories of life's origin including Aristotle's theory, Pasteur, Redi and Leuwenhook experiment, Abiogenesis, etc.
Fossils and its evolutionary significance.
Touring the Universe (An Introduction to Formation of the Universe)
I hope this lesson can shed light to SHS Grade 11 Science Teachers. My appeal to those who will download this ppt. please email me at marileahmendina08@gmail.com for my own references. I would be glad to hear from you.
Lesson 2 We Are All Made of Star Stuff (Formation of the Heavy Elements)Simple ABbieC
Content: How the elements found in the universe were formed
Content Standard:
At the end of the lesson, you will be able to demonstrate an understanding of:
the formation of the elements during the Big Bang and during stellar evolution
the distribution of the chemical elements and the isotopes in the universe
Learning Competencies:
At the end of the lesson,
Give evidence for and describe the formation of heavier elements during star formation and evolution (S11/12PS-IIIa-2)
Write the nuclear fusion reactions that take place in stars that lead to the formation of new elements (S11/12PS-IIIa-3)
Describe how elements heavier than iron are formed (S11/12PSIIIa-b-4))
Keys to Student-Centered Learning (Creating a Student-Centered Learning Climate)Simple ABbieC
Keys to Student-Centered Learning
(Creating a Student-Centered Learning Climate)
- Setting high social and academic expectations
- Creating school environments focused on the needs of the learner
Ore Minerals (How it is found, mined, and processed for human use)Simple ABbieC
Department of Education | Senior High School
Topic: Ore Minerals (How it is found, mined, and processed for human use)
Learning Competency:
Earth Science (for STEM): Describe how ore minerals are found, mined, and processed for human use. (S11ES-Ic-d-8)
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Minerals / Common Rock-forming Minerals and their Physical and Chemical Prope...Simple ABbieC
Department of Education | Senior High School
Topic: Minerals / Common Rock-forming Minerals and their Physical and Chemical Properties
Learning Competency:
Earth and Life Science: Identify common rock-forming minerals using their physical and chemical properties.
Earth Science (for STEM): Identify common rock-forming minerals using their physical and chemical properties.
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Planet Earth and its properties necessary to support lifeSimple ABbieC
Department of Education | Senior High School
Topic: Planet Earth and its properties necessary to support life.
Learning Competency:
Earth and Life Science: Recognize the uniqueness of Earth, being the only planet in the Solar System with properties necessary to support life.
Earth Science (for STEM): Describe the characteristics of Earth that are necessary to support life.
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EARTH MATERIALS AND PROCESSES
Topic: Classification of Rocks / Types of Rocks
Senior High School | Earth and Life Science
Learning Competency: Classify rocks into igneous, sedimentary, and metamorphic. (S11/12ES-Ib-10)
Senior High School | Earth Science
Learning Competency: Classify rocks into igneous, sedimentary, and metamorphic. (S11ES-Ic-6)
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Earth and Life Science
Earth Materials and Processes: Deformation of the Crust
The learners shall be able to:
1) explain how the seafloor spreads (S11/12ESId-23);
2) describe the structure and evolution of ocean basins (S11/12ES-Id-24); and
3) explain how the movement of plates leads to the formation of folds and faults (S11/12ES-Id-22).
Specific Learning Outcomes
At the end of the lesson, the learners will be able to:
1. Discuss the history behind the Theory of Continental Drift;
2. Describe the Continental Drift Theory;
3. Enumerate and explain the evidence used to support the idea of drifting continents;
4. Identify major physiographic features of ocean basins
5. Describe the process of seafloor spreading
Earth and Life Science
Earth Materials and Processes
Deformation of the Crust: Continental Drift Theory
Learning Competencies
The learners shall be able to explain how the continents drift (S11/12ESId-20), and cite evidence that support continental drift (S11/12ES-Id-21).
Specific Learning Outcomes
At the end of the lesson, the learners will be able to:
1. Discuss the history behind the Theory of Continental Drift;
2. Describe the Continental Drift Theory; and
3. Enumerate and explain the evidence used to support the idea of drifting continents.
Lesson 5: Corpuscles to Chemical Atomic Theory (The Development of Atomic The...Simple ABbieC
At the end of the lesson, you will have to:
1. cite the contribution of John Dalton toward the understanding of the concept of the chemical elements
2. explain how Dalton’s theory contributed to the discovery of other elements.
Earth Materials and Processes : ENDOGENIC PROCESSSimple ABbieC
Earth Materials and Processes : ENDOGENIC PROCESS
Content Standard:
The learners demonstrate an understanding of:
geologic processes that occur within the Earth and
the folding and faulting of rocks
Lesson 4 Not Indivisible (The Structure of the Atom)Simple ABbieC
Learning Competencies
At the end of the lesson, you will have to:
1. point out the main ideas in the discovery of the structure of the atom and its subatomic particles
2. cite the contributions of J.J. Thomson, Ernest Rutherford, Henry Moseley, and Niels Bohr to the understanding of the structure of the atom
3. describe the nuclear model of the atom and the location of its major components (protons, neutrons, and electrons)
Lesson 3 Atomos, Aristotle and Alchemy (Chemistry Before Modern History)Simple ABbieC
Lesson 3 Atomos, Aristotle and Alchemy (Chemistry Before Modern History)
CONTENT:
How the idea of the atom, along with the idea of the elements evolved
CONTENT STANDARD
At the end of the lesson, you will have to describe:
1. how the concept of the atom evolved from Ancient Greek to the present; and
2. how the concept of the element evolved from Ancient Greek to the present
LEARNING COMPETENCIES
At the end of the lesson, you will have to:
1. describe the ideas of the Ancient Greeks on the atom (S11/12PS-IIIa-b-5)
2. describe the ideas of the Ancient Greeks on the elements (2 hours) (S11/12PS-IIIa-b-6)
3. describe the contributions of the alchemists to the science of chemistry (S11/12PS-IIIb-7)
Core Subject: Earth and Life Science
II. Earth Materials and Processes
A. Minerals and Rocks
The learners
demonstrate an
understanding of:
1. the three main categories of rocks
2. the origin and environment of formation of common minerals and rocks
The learners:
1. identify common rock-forming minerals using their physical and chemical properties
2. classify rocks into igneous, sedimentary, and metamorphic
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
Students, digital devices and success - Andreas Schleicher - 27 May 2024..pptxEduSkills OECD
Andreas Schleicher presents at the OECD webinar ‘Digital devices in schools: detrimental distraction or secret to success?’ on 27 May 2024. The presentation was based on findings from PISA 2022 results and the webinar helped launch the PISA in Focus ‘Managing screen time: How to protect and equip students against distraction’ https://www.oecd-ilibrary.org/education/managing-screen-time_7c225af4-en and the OECD Education Policy Perspective ‘Students, digital devices and success’ can be found here - https://oe.cd/il/5yV
Ethnobotany and Ethnopharmacology:
Ethnobotany in herbal drug evaluation,
Impact of Ethnobotany in traditional medicine,
New development in herbals,
Bio-prospecting tools for drug discovery,
Role of Ethnopharmacology in drug evaluation,
Reverse Pharmacology.
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
2. HOMOLOGY AND
EVOLUTION
Homology is the existence of shared ancestry between a pair of
structures, or genes, in different taxa. A common example of
homologous structures is the forelimbs of vertebrates, where
the wings of bats, the arms of primates, the front flippers
of whales and the forelegs of dogs and horses are all derived from
the same ancestral tetrapod structure.
Evolutionary process is not a haphazard event in nature that
simply happened in a short period of time. Evolution is almost
close to the concept of change.
To evolve means to change. This change, however, is not on the
individual species but on the population.
A lot of people find it hard to embrace the concept of evolution
because they believe that it is opposed to their faith especially on
the concept of creation.
3. The limbs are shaped differently
because their lifestyles’ or how they
live are different from one another.
What is interesting, however, is that
their forelimbs, have the same set of
bones.
The limbs of animals called tetrapodor
animals with four legs. However, not
all tetrapods have four legs. Tetrapods
also include animals without four feet
such as whales and snakes.
They used to have limbs but have lost
their them as they migrate or return to
water and stayed there for some time.
Whales bones unearthed in excavation
sites in Pakistan and Egypt showed that
ancient whales used to have four limbs
but eventually lost two of them
specifically their hind legs. The front
legs are now flippers.
4. Amphibians, reptiles, and mammals
are classified as tetrapods. Humans
are classified as tetrapods although
we walk with only two legs. The
ancestors of present-day tetrapods
lived in the water. What is surprising
is that they evolved from finned
organism.
Homology simply indicates that
although organism or animals are
totally different, they have certain
traits common to all of them inherited
from a common ancestor.
They became totally different today
from what they were before because
they have evolved. Homologous
structures are not only common in the
animal kingdom;
5. The leaves of these plants are not the typical green leaves we
see around us. Their function is not basically to perform
photosynthesis but either to provide the plant with nutrients
which the soil cannot provide or inadequately cannot give.
Pitcher plant and the venus flytrap are carnivorous plants. They
‘eat’ insects. Poinsettia’s bright read leaves are called bracts to
attract pollinators. The prickly spines of cacti are modified
leaves to give them protection from animal predators and to
shade them from heat. The shape and function of each plant in
is different, yet, they are all leaves modified to help the plant
adapt and survive their own unique environment. Modified
leaves in plants are example of homologous structures.
6. FOSSIL RECORDS AND
EVOLUTION
Some of the ratites. They are found in South America,
Africa, Australia, Papua New Zealand. Like present-day
birds are sometime called avian dinosaurs. Scientifically
speaking, birds are reptiles.
7. It is interesting to know that the very first
commercial ostrich farm in the country is
located in Cagayan De Oro. It first
opened in 1996 with just three pairs of
breeding ostriches imported from
Australia. The meat and egg of ostriches
very high in protein but low in cholesterol
compared to chicken.
Elephant birds are the largest bird that
ever lived on Earth. They stand 10 feet
tall and weigh more than 450 kilograms.
Elephant birds roamed Madagascar 60
million years ago during the time when
birds ruled the Earth. They have strong
and massive legs, long claws, and
powerful neck. Their eggs which are
about 170-200 times bigger than the
chicken eggs, enough to feed a family for
a day, were hunted for food (Extinct
Animals, 2015).
8. Marco Polo once wrote of a giant bird he saw in the late
13th century. Elephant birds existed until the 17th century.
Their extinction was attributed to human activity.
Collectively called ratites, elephant birds, like ostriches,
rheas, kiwis, and all other birds, evolved from a two-legged
carnivorous dinosaurs called therapods during Late
Jurassic Period (University of California Museum of
Palaeontology, n,d; Sanger, 2015). Two of the well-known
members of the therapods are the towering Tyrannosaurus
rex and the velociraptors.
9. The existence of T. Rex, velociraptor, and other dinosaurs were
proven by the discovery of their fossil remains. T. Rex fossils were
discovered in places like Alberta, Canada and Texas (Castro 2016).
The first velociraptor fossil was found in Gobi Desert, Outer
Mongolia in 1923 by Peter Kaisen of the American Museum of
Natural History (Castro, 2016).
10. The bones of the chicken is smaller and
are proportioned to its size whereas the
bones of Allosaurus are thicker and
shorter to support its size.
Evolutionary biologists established that
the transformation (evolution in terms of
size and appearance) of the dinosaurs to
modern day birds did not occur in a snap
but gradual. Changes in features happen
one at a time (Sanger, 2015).
Sanger (2015) described the transition as
“first bipedal locomotion, then feathers,
then a wishbone, then more complex
feathers that look like quill-pen feathers,
then wings.” Dinosaurs first transformed
into a sparrow-size prehistoric bird called
IBEROMESORNIS.
Fossil remains of Iberomesornis are found
in Spain. According to www.prehistoric-
wildlife.com. (n.d), Iberomesornis ) “are
considered to represent an intermediate
stage in bird evolution before the
appearance of,? More advanced forms
closer to modern birds”
11. EXTINCTION OF
SPECIES
Everyday, a new species of plants or animals is being discovered. However,
the sad part is many are disappearing faster before they can be studied in
Science
You might have heard of Charles Darwin and how his historic five-years
voyage aboard HMS Beagle including his visit to the island of Galapagos
helped him formulated his theory of evolution.
His book Origin of Species contains his thoughts on evolution., and for this,
Darwin is regarded today as the Father of Evolution.
Extinction is a serious threat to the perpectuation of life. It is not just an
environmental problem confined in one location or in several locations in this
planet.
It is a social problem that threatens our survival as human being because life
on Earth is interconnected.
An invisible thread connects all creations on this beautiful planet. Everything
is affected whenever one species vanished from the face of the Earth. When a
species become extinct, it goes with it its own gene pool which is lost forever.
12. DARWIN’S VOYAGE AND ON THE
ORIGIN OF SPECIES AND THEORY
OF EVOLUTION
Have you ever wondered how Darwin came up with his grand theory of
evolution? Or what shaped his idea on evolutionary by natural selection?
Great ideas are always inspired by the things we see around us by own
experiences. Sometimes, our ideas are influenced by what we read or hear.
In his case, Darwin was heavily influenced by the things he saw on his five-
year trip.
It should be emphasized that Darwin had already conceptualized the idea of
evolution by natural selection long before joining the trip.
For Darwin, a naturalist, the distillation of his idea on evolution by natural
selection is a product of so many things, foremost of which is his visit in the
Galapagos Island aboard HMS Beagle, already on its second expedition.
Darwin was only 22 at that time when he was selected to join and a fresh
graduate from Cambridge. His task, as a naturalist was to collect samples of
plants and animals, including rocks.
13. THEORY OF EVOLUTION
BY NATURAL
SELECTION
Darwin’s ideas on evolution are extensively explained in his book
“On the Origin of Species” published in 1859. His ideas created a
lot od controversies especially with the religious authorities who
found his views in conflict with the Bible on the idea of creation.
The fundamental tenet of Darwin’s idea is that all the different
species have evolved from simple organisms and that include
humans.
The first life, which is a single-celled organisms, evolved more
than 3.5 billion years ago or about 1.5 billion years after the Earth
was formed.
14.
15. NATURAL SELECTION
IN ACTION
The theory of evolution states that evolution happens by natural selection.
The concept of natural selection is very important in understanding evolution.
It is one of the basic mechanisms answer the question “How organism
evolved?”
Nature, select the traits that have the best chance to survive and reproduce.
These traits are encoded in their genes and are transmitted from one
generation to another, that is, they are inheritable. Natural selection is nature’s
gatekeeper or control quality mechanism.
The heritable trait is fur color. This is encoded in the genes, is transmitted
from generation to generation. Heritable trait increases fitness. It enables the
organism to survive and reproduce. Heritable trait like fur color that increases
fitness called adaptive heritable trait. Adaptive heritable traits are important
in natural selection.
16.
17. AND ORIGIN OF
SPECIES
The formation of different species of honeycreepers is an
example of adaptive radiation, a rapid evolution wherein several
new species is created from a founder species in a short period
of time.
18. SPECIATION
Study the figure. It is phylogeny that shows a polytomy. A polytomy is a
node where several descendants emerge from a single ancestor. Whenever
a phylogenetic tress shows a polytomy or polytomies, it conveys two
things; available data are not sufficient to explain how it gave rise to
several descendants or it is possible that a simultaneous speciation occurs
among descendants. The case of honeycreepers is an example of a
phylogeny showing polytomy.
Speciation describes how a new kind of plant or animal species is created.
It occurs when a group within a species separates from other members of
its species and develops its own new and distinct species is formed in the
course of evolution.
To better grasp the concept of speciation let us first define the term
species. A species is the basic category of biological classification. It
refers to a group of organisms or individuals that actually or potentially
interbreed in nature, This definition is totally different from the typical
definition that defines species as;
“Composed of related individuals that resemble one another, are able to
breed among themselves, but are not able to breed with members of an
other species”.
19.
20. There are five types of speciation in nature; allopatric, peripatric, and
sympatric and artificial.
1. Allopatric speciation – occurs when members of a species are
separated into two groups due to physical barriers.
2. Peripatric speciation – occurs when small groups of individual in a
population separate from the larger group and form a new species
3. Parapatric speciation – occurs when a species occupies a large
geographic area.
4. Sympatric speciation – occurs due to reproductive isolation.
5. Artificial speciation – occurs when human beings intervence in the
natural reproduction using techniques or technology to create new
species specifically for economic benefits.
21. EXTINCTION OF
SPECIES
Dinosaurs appeared 230 million years ago and ruled the earth for more than
135 million years. It was Richard Owen who first introduced the term
dinosaur in 1842. The term is derived from two Greek words deinos, which
means “terrible” “fearfully great,” and sauros, meaning “lizard” or reptile
(Gammon, 2016)
Dinosaurs, the largest land animals that ever roamed the Earth, became extinct
65 million years ago. Everything we know about them was derived from the
analysis of their fossils found in different parts of the world. Palaeontologists
unearthed complete bones of heses reptiles in good condition giving us a good
picture of how they looked like and lived. Dinosaurs are not the only extinct
animals on Earth, there are many more including plants and other organisms.
22.
23. EXTINCTION Extinction is a serious ecological problem. The extinction of one species
affects the rest of ecosystem because all creation are interconnected by an
invisible thread of life. Extinction means end of the species. It occurs when
the last member of the population dies.
A species is said to be extinct when no member of the species remains alive
anywhere in the world. A species said to be extinct in the wild if the only
surviving member is in captivity. A captive species is usually found in
research of breeding centers.
On one hand, a species is said to be locally extinct or extirpated if it is no
longer found in the area where it used to live and is found somewhere else.
The species outside its natural habitat.
Darwin argued that extinction is a natural phenomenon as a consequence of
evolution. According to him, extinction occurs whenever organisms fails to
adapt to the changing and water.
This is true for normal process of extinction or natural extinction process.
Causes if natural extinction process are demographic failure or genetic
swamping, speciation or anagenesis. Anagenesis oranagenetic evolution is
evolution within a lineage. It refers to the collective changes that transform
one species into a different species with different characteristic. The increase
in cranium size of humans is an example of anagenetic evolution.
24. CAUSES OF NORMAL
PROCESS OF
EXTINCTION
The Earth has already experienced five main mass extinction events. Mass extinction
is a rapid geologic even that takes place in a few million years. It occurs when at least
half of all species die in a short period of time due to a catastrophic event like
massive earthquake, comet and asteroid bombardments, glaciation, sudden global
temperature change, or disease.
The largest mass extinction occurred 250 million years ago with 95% of all species
were extinct. During mass extinction, old species are replaced with a new one.
Mass extinction is supported by fossil records. Palaeontologists at the American
Museum of Natural History observed “fossils that are abundant in earlier rock layers
are not present in later rock layers.”
A wide range of animals and plants suddenly died out, from tiny marine organisms to
large dinosaurs. The sudden demise of dinosaurs of the Cretaceous-Tertiary
extinction event (K-T event) that happened 65.5 million years ago, is an example of
mass extinction.
Mass extension should not be taken negatively. It is a normal cycle of life in this
planet. Mass extinction causes new life forms to emerge. For instance, the mass
extinction of dinosaurs allowed mammals to diversity and evolve.
25. EXTINCTION
EVENTS
Palaecontologists recognize five main extinctions events, also known as the Big 5
1. The late Ordovician event 348 million years ago, when 100 families went
extinct.
2. Late Devonian event 360 million years ago, when 30% of families went extinct.
3. End Permian event 245 million years ago, the biggest extinction of all the time
when over 50% of all families were lost.
4. Late Triassic event 35% of families died out.
5. The Cretaceous Tertiary (K-T) event 65 Million years ago, which ended the reign
of the dinosaurs.
26. SIXTH MASS
EXTINCTION
Scientists anticipate another mass extinction and call it the sixth mass
extinction in the history of planet Earth. This expected mass extinction is
being caused by destructive human activities (destructive fishing, land
clearing, pollution, mining, etc) and uncontrolled population growth.
According to International Union for Conservation of Nature, destructive
human activities have caused extinction of about 514 animal species since
the beginning of the 15th century. It is during this period that Industrial
Revolution started.
Extinction of plants and animals has irreversible consequences to humans.
The potential of this organism as possible source of medicine for dreaded
forms of cancer, hypertensions, kidney failure, depression, fever, etc., is
forever lost.
27. Complete extinctions of plants in the rainforest is a serious environmental
problem with huge social implications.
Marine organisms also face threat of extinction brought by destructive human
activities. Our reliance on fossil fuels contributes to ocean acidification which
has serious effects on marine organisms. For instance, coral bleaching is
attributed to ocean acidification. As the ocean slightly becomes more acidic,
the ability of shell-forming marine organisms like corals, oysters, shrimp,
lobster, scallops, clams, and many planktonic organisms, and even some fish
species is affected.
Ocean acidification also effect the size of shelled organisms, for instance,
clams grow smaller. The rate of extinction of marine organisms is almost
similar to the rate of terrestrial extinction. Signs that marine extinction is
gaining ground are: decline in abundance of marine vertebrates of 22%
decline in marine fishes by 38% and decline in population of baleen whales by
80 to 90%.