LESSON 1: REPRODUCTION AS A CHARACTERISTIC OF LIFE
How do we know that it is an inanimate object?
CHARACTERISTICS OF LIFE:
• REPRODUCTION – an object or organism is considered a living if it has the ability to reproduce
on its own, thus implying a continued existence of the organism’s population.
• All living organisms, from a single-celled amoeba to a 72 trillion-celled human, have an innate
drive – not simply a desire-to reproduce
• RESPONSE TO THE ENVIRONMENT – organisms respond to diverse stimuli.
e.g. Plants can bend toward a source of light, climb fences and walls or respond to touch
(Mimosa Pudica or makahiya plant).
e.g. Tiny bacteria moving toward or away from chemicals (chemotaxis) or light
(phototaxis).
• REGULATION (Adaptation) – the ability to self-regulate. Even smallest organisms are complex
and require multiple regulatory mechanisms to coordinate internal functions, respond to stimuli,
and cope with environmental stresses. Two examples of internal functions regulated in
organisms are nutrient transport and blood flow. Organs (groups of tissues working together)
perform specific functions, such a carrying oxygen throughout the body, removing wastes,
delivering nutrients to every cell and cooling the body.
e.g. Sweating when temperature is high and frequent urinating when it’s cold.
• ORDER – organisms are highly organized, coordinated structures that consist of one or more
cells. Even very simple, single-celled organisms are remarkably complex: inside each cell, atoms
make up molecules, these in turn make up cell organelles and other cellular inclusions.
e.g. A toad (multicellular organism): similar cells form tissues, tissues in turn collaborate
to create organs (body structures with a distinct functions). Organs work together to form organ
systems (digestive system, reproductive system, respiratory system, integumentary system,
skeletal system, muscular system, etc.).
• EVOLUTIONARY ADAPTATION – a biological mechanism by which organisms adjust to new
environments or to changes in their current environment.
e.g. Biological adaptation – there is an alteration of the body functions.
People living at high altitudes such as Tibet. Tibetans thrive to altitudes where oxygen
level is 40% lower that at sea level. Breathing air that thin would cause most people to get sick,
but Tibetans’ bodies have evolved changes in their body chemistry. They seemed to have
