INTRODUCTION TO LIFE SCIENCE GRADE 11.pdf

THEORIES ON THE ORIGIN OF LIFE

1. INTRODUCTION TO LIFE
SCIENCE

2. CONCEPT OF LIFE
Life on Earth began more than 3 billion years ago, evolving
from the most basic of microbes into an array of complexity
over time.
Every aspect of life from the smallest submicroscopic living
particle to the largest and most imposing of plant and animal
species is included.
All living things are made of cells. Some organisms are
unicellular and some are multicellular.

3. TYPES OF ORGANISMS
Unicellular organisms are living things made up of only one cell, and
that single cell performs all the functions necessary for life, such as
nutrition, reproduction, movement, and response to the environment.
BACTERIA AMOEBA
PARAMECIUM
EUGLENA

4. TYPES OF ORGANISMS
Multicellular organisms are living things made up of many cells that
work together. Unlike unicellular organisms, they have specialized cells
for different functions.

5. CHARACTERISTICS OF LIFE
The Characteristics of Life are the basic
features or qualities that all living things share,
which distinguish them from nonliving things.
They are the essential processes and traits
that define living organisms, showing that they
are alive and capable of carrying out life
functions.

6. CHARACTERISTICS OF LIFE
1. Organization – All living things are made of the basic
unit of life we called cells that emerges from pre-existing
ones.

7. Robert Hooke (1665)
Discovery: Using a simple compound
microscope, Hooke examined thin slices
of cork. He observed small box-like
compartments, which reminded him of
the small rooms (cells) where monks
lived.
Contribution: He coined the term “cell”.
However, what he actually saw were the
dead cell walls of plant tissue, not living
cells.
Impact: Hooke’s work marked the
beginning of cell biology and introduced
the concept of cells as structural units.

8. Anton van Leewenhoek (1673)
Discovery: With his handmade high-powered
lenses (up to 300× magnification), he was the
first to observe living single-celled organisms
in pond water. He described them as
“animalcules.”
Contribution: Observed bacteria, protozoa,
sperm cells, and red blood cells, revealing that
life exists beyond what the naked eye can
see.
Impact: Leeuwenhoek is often called the
“Father of Microbiology”, as he proved the
microscopic world is alive.

9. Matthias Schleiden (1838)
Discovery: As a botanist, Schleiden
studied numerous plant tissues under
the microscope. He concluded that all
plants are made of cells and that the
cell is the basic building block of plant
life.
Contribution: Established that the cell
is the fundamental unit of plants.
Impact: His work laid the foundation for
the idea that cells are universal in living
things.

10. Theodor Schwann (1839)
Discovery: A zoologist who studied
animal tissues. He found that all
animals are also made up of cells.
Contribution: Alongside Schleiden, he
generalized that all living things (plants
and animals) are composed of cells.
Impact: This was the first formulation
of the Cell Theory — stating that the
cell is the basic unit of life in all
organisms.

11. Rudolf Virchow (1855)
Discovery: Based on his studies in
pathology, Virchow observed that new cells
are formed only by the division of existing
cells.
Contribution: He stated “Omnis cellula e
cellula” (all cells come from cells),
disproving the idea of spontaneous
generation.
Impact: Completed the modern Cell Theory,
which emphasizes both the structural role
of cells and their ability to reproduce.

12. Organization
In their collective contribution, they, together
created a theory called the Cell Theory which
states that:
1.All living organisms are made up of one or
more cells.
2.The cell is the basic unit of structure and
function in living things.
3.All cells arise only from pre-existing cells.

13. CHARACTERISTICS OF LIFE
2. Metabolism – Living organisms obtain and
use energy to carry out processes like growth
and repair. Catabolism and Anabolism

14. CHARACTERISTICS OF LIFE
Catabolism breaks down big complex molecules into
smaller, easier to absorb molecules. The process of
catabolism releases energy.
Anabolism builds molecules required for the body’s
functionality. Anabolic processes require energy.

15. CHARACTERISTICS OF LIFE
3. Homeostasis – They maintain a stable internal
environment despite changes around them. Positive and
Negative Feedback Mechanism
Negative Feedback- A process in which
the body reverses a change to bring
conditions back to normal.
Positive Feedback- A process in which
the body intensifies or amplifies a change
until a specific outcome is reached.

16. CHARACTERISTICS OF LIFE
4. Growth and Development – They grow in size
and undergo life cycle changes.
This means that there is an increase in the size or
number of cells in an organism and change and
maturation an organism undergoes during its life cycle
that involves structural, functional, and behavioral
changes.

17. Cell Division
Mitosis: Mitosis occurs in somatic (body) cells and is responsible for
growth, repair, and asexual reproduction. In this process, a single cell
divides once to produce two identical daughter cells, each containing
the same number of chromosomes as the parent cell. This ensures
that genetic information is maintained across new cells.

18. Cell DivisionMeiosis, on the other hand, occurs only
in sex cells (gametes such as sperm
and egg). It involves two successive
divisions—meiosis I and meiosis II—
that result in four non-identical
daughter cells, each with half the
number of chromosomes of the original
cell. This reduction is important to
maintain the species’ chromosome
number during sexual reproduction, and
the genetic variation it introduces
through crossing over.

19. Life stages
Infancy (0–2 years) – Rapid brain development, learning to crawl, stand, walk, and
beginning to talk. Emotional attachment and recognition of caregivers develop.
Early Childhood (3–6 years) – Development of language, imagination, and basic motor
skills like running, drawing, and dressing oneself. Social skills begin as children play with
others.
Late Childhood (7–12 years) – Cognitive development, improved problem-solving,
logical thinking, and learning academic skills. Social development grows with teamwork,
friendships, and following rules.
Adolescence (13–19 years) – Emotional and social development as identity,
independence, and self-awareness increase. Intellectual development includes
abstract thinking and decision-making.

20. Life stages
Early Adulthood (20–39 years) – Development of independence, career building,
intimate relationships, and life responsibilities.
Middle Adulthood (40–59 years) – Emotional and social development through
stability, leadership, and guiding the next generation (parenting/mentoring).
Late Adulthood (60+ years) – Development centers on wisdom, reflection, and
adaptation to aging. Some may focus on leaving a legacy or finding fulfillment.

21. CHARACTERISTICS OF LIFE
5. Reproduction – They produce offspring to
continue their species.
Types of Reproduction- Asexual and Sexual
Reproduction
Asexual: Involves only one parent.
Sexual: Involves two parents.

22. Types of Asexual Reproduction
Binary Fission – A parent cell splits into two identical daughter cells. The parent cell
duplicates its DNA, then splits into two equal parts, each with the same genetic
material.
Example: Amoeba, Paramecium, bacteria.

23. Types of Asexual Reproduction
Budding – A small outgrowth (bud) develops on the parent’s body, grows, and
eventually detaches to form a new organism. A small bulge (bud) forms on the
parent’s body. The bud grows, develops organs, and then detaches to live
independently.
Example: Hydra, yeast.

24. Types of Asexual Reproduction
Fragmentation – The parent’s body breaks into pieces, and each piece can
regenerate missing parts to become a complete organism.
Example: Starfish, flatworms (Planaria).

25. Types of Asexual Reproduction
Spore Formation – The parent produces tiny, lightweight spores protected
by a tough coat. When conditions are favorable (moisture, nutrients),
spores germinate into new individuals.
Example: Mushrooms release spores that grow into new fungi

26. Sexual reproduction, on the other hand, requires two parents and involves
the fusion of male and female gametes (sperm and egg). This produces
offspring that are genetically unique, combining traits from both parents.
Formation of Gametes – Specialized sex cells (gametes) are produced
through meiosis.
Male gametes = sperm cells.
Female gametes = egg cells (ova).
Types of Sexual Reproduction

27. CHARACTERISTICS OF LIFE
6. Response to Stimuli/Irritability – Living organisms react to
changes in their environment.
Touch Reflex: Pulling your hand back when you touch something hot.
Light Response: Pupil of the eye gets smaller in bright light and larger in darkness.
Sound Response: A dog turning its head when it hears a whistle.
Phototropism: Plant stems bend toward light (sunflower turning toward the sun).
Gravitropism/Geotropism: Roots grow downward toward gravity, while shoots grow
upward.
Thigmotropism: Climbing plants like vines coil around objects when they touch
them.
Flower Opening/Closing: Morning glory opens during daylight, closes at night.

28. CHARACTERISTICS OF LIFE
7. Adaptation/Evolution – Populations change over time to
better survive in their environment.
Adaptation – The process by which living things develop features or
behaviors that help them survive and reproduce in their environment.
Evolution- Happens when adaptations accumulate in a population over
many generations.
Driven by natural selection (the “survival of the fittest”).

29. Adaptation and Evolution
Peppered moths are known for their light-
grey colour with black spots, helping
them blend in with tree trunks covered in
lichen.
There is also a black variation of
peppered moths called 'melanic'. But
since they stand out against the lichen-
covered trunks, they’re more likely to be
eaten by predators, so they're less
common than the lighter-coloured moths.

30. Adaptation and Evolution
In the 19th century, black peppered
moths thrived in urban areas where
industrialisation and coal fires caused
pollution. The darker moths blended in
better with the soot-covered tree
trunks, making them less visible to
predators.
This gave them an advantage in survival
and reproduction, increasing their
population compared to the lighter-
coloured moths.

31. Adaptation and Evolution
In the mid-20th century, controls
were introduced to reduce air
pollution.
Tree trunks became cleaner and
lichen growth increased. This
encouraged the resurgence of the
population of lighter-coloured
peppered moths.

32. CHARACTERISTICS OF LIFE
8. Locomotion/Movement – Living things show movement,
either by the whole organism (like animals walking, swimming,
flying) or parts of it (like plants opening flowers or roots
growing toward water).

33. Group Reporting
GROUP 1:
Special Creation Theory
Spontaneous Generation Theory
GROUP 2:
Biogenetic Theory
Abiogenetic Theory
GROUP 3:
Panspermia (Cosmozoic Theory)
Hydrothermal Vent Hypothesis
GROUP 4:
Endosymbiotic Theory
RNA World Hypothesis
Theories on the Origin of Life

34. Group Reporting
G1: SOLLANO, MEPIEZA, MAANO, SUSVILLA, YLANAN
G2: ARAGON, SALVE, DIGNOS, VOSOTROS, LEPON
G3: GULBE, AMORES, WENCESLAO, ROSOS, SEVILLENO
G4: CONEJOS, HEMPEROSO, PABALAN, DELA CRUZ
Theories on the Origin of Life

35. Guidelines:
Each group shall research on the topic the have been provided.
They shall come prepared and report their assigned topic in
front of the class strictly on the scheduled time.
Each member of the group shall have a role and contribution to
the process and subsequent success of their assigned task.
Each group shall articulately present their findings in an
organized manner while showcasing in-depth analysis,
providing explanations relevant to the topic.
READING OF PPT WITHOUT OWN EXPLANATION IS
HIGHLY DISCOURAGED.

36. Criteria Description Percentage
Content Accuracy
Information is correct, complete, and relevant to the topic. Demonstrates
understanding of concepts. Provides examples and evidences that
coincides with the topic.
25%
Organization & Clarity
Ideas are presented in a logical order. The report is easy to follow, with
clear introduction, body, and conclusion.
25%
Presentation Skills
Group members speak clearly, confidently, and maintain eye contact.
Proper voice projection, pacing and professionally mannered. Showcase a
wide understanding of the topic.
20%
Teamwork/Collaborati
on
All members actively participate. Tasks are evenly distributed and
coordinated.
20%
Creativity and
Engagement
Report is engaging and original. Includes examples, illustrations, or
interactive elements.
10%