Biology- literally means “study of life”.

It comes from two Greek Words, arose from living matter such as maggots from eggs not from inanimate
“bios” (life) and “logos” (reason or study”. objects.
2. Needham’s Experiment-
-Science that deals with structures, functions and relationships of living English priest John Needham challenged Redi’s experiment. This experiment
things and their environment. It is a broad field and may be studied at various focuses on the common knowledge that boiling could kill micoorganisms and
levels- molecular, cellular, organismal, population, community or whether or not microorganisms can appear after boiling.
ecosystems. 3. Spallanzi’s Experiment-
Italian scientist Lazzaro Spazallani challenged Needhams experiment. His
Traditional Major Divisions of Biological Sciences: experiment focused on the idea that life occurred under the presence of air
1. Microbiology- Study of microorganisms 4.Pasteur Experiment
2. Botany- study of plants Louis Pasteur experiment convinced most scientist about the theory of
3. Zoology- study of animals biogenesis. His experiment made evidence suggesting that new bacteria
Sub-divided into Specialized Branches: appear only when they are produced by existing bacteria.
1. Taxonomy- naming and classifying organisms Unifying Themes about Life
2. Cytology- structures and functions of cells
- Living things on Earth share common characteristics or properties typically
3. Embryology- formation and development of organisms
not found in inanimate things.
4. Anatomy- structures and parts of organisms
5. Physiology- functions of living organisms and their parts
1. Gathering and Using Energy- one unique characteristic of living things
6.Biochemistry- biochemical compositions of living things
- Energy is the ability of organisms to do work that allows them to move.
7. Genetics- heredity and variation
- In order to perform vital activities such as growth, movement and
8. Evolution- origin and differentiation of various organisms
reproduction, all living things require energy.
9. Ecology- relationships of organisms with their environment
Modes of Obtaining Energy
 Photosynthesis – derivation of energy directly from sunlight
Early Beliefs about the Origin of Life
 Ingestion - derivation of energy from other organisms or food. Energy is
1. Spontaneous Generation/ Abiogenesis- is the idea that life could appear
produced when complex organic matters such as carbohydrates and
from non-living material. This idea was proposed by Aristotle.
proteins are broken down into simple substances such as glucose and
2. Biogenesis- is the belief that life originates from pre-existing life.
amino acids. The process by which energy is released by the breakdown
of food substances is called Cellular Respiration
Several Experiments: Nutrient Uptake and Processing
1. Redi’s Experiment_
 Nutrition- the process by which organisms acquire food
Italian Physician Fransesco Redi conducted an experiment that challenged the
(plants,animal,microorganism VS nonliving things like cotton)
idea of spontaneous generation. His experiment focused on the idea that life
 Enzymes- help regulate the rate at which the reactions occur including
the amount of nutrients to be processed into other forms
 Waste Elimination Two Ways of Reproduction
 Homeostasis- the maintenance of the body’s internal environment 1. Sexual Reproduction- organisms reproduce with the use of two individuals
2. Adapting and Evolving contributing their sex cells to produce a unique individual of their kind.
a- Motility/Locomotion- enables most animal to another by walking, flying, 2. Asexual Reproduction- occurs when an organism makes copies of itself, as
swimming, gliding, creeping, blooming or jumping. Ex. Cilia, Flagella and commonly found in lower life forms.
Pseudopods, Foot, Wings c- Heredity: Unity Amidst Diversity- presence of DNA, differs in forms but
b- Irritability/Sensitivity- the ability to respond appropriately against a same in composition.
stimulus. It is the response to light, sound, temperature, pressure, food 4. Organization of Life- the scope of life on Earth is so immense but it can
sources. be viewed in to two dimensions, both following the Hierarchical Levels of
c.- Adaptation- the ability to adjust to changes in the environment due to the Biological Organization
variation, threat and changes - exhibits high degree of organization from molecular to cellular level.
d- Evolution- refers to the changes in characteristics of a group of organisms Single Cellular Organisms- possesses only certain parts of a cell
(population) over time. Evolutionary adaptation is a gradual or rapid change Multicellular Organisms- groups of cells form tissue and different tissues form
in body structure or behaviour to be better suited and to survive a new organs, different organs comprise an organ system with a specialized function.
environment. An Organism interacts with other organisms of the same kind known as
3. Reproducing and Continuing Life- certain life properties relate to an population, while an array of populations sharing their habitat compose a
increase in the size of the organism or increase in the number of organisms. community. These communities exist in an environment affected by both living
Growth, development and reproduction are processes that require and non-living components known as ecosystem. All ecosystems on Earth
metabolism because they cannot occur without nutrient uptake and whether they support life on land, water or lower atmosphere make up what
processing. we call the biosphere.
a- Growth- is the increase in size and volume by converting food to become a
part of body cells.
Intussusception- process where in living things exhibit growth from within the
cells
Organogenesis- growth involves more complex process of cell differentiation
and formation of new organs (batong buhay VS Scar
formation)
Accretion- growth by external addition of substances
b- Development and Reproduction- Development refers to the defined stages
a living thing undergoes in their life cycle which starts with birth and ends in
death. Reproduction is a process by which genetic information is passed on
from one generation to another as organisms produce offspring that resemble
their parents.