Characteristics of Living Things

Characteristics of Living Things

• Living things exhibit seven vital functions: nutrition, respiration, excretion, growth, movement, sensitivity, and reproduction.
• Each of these functions is essential for an organism to survive and reproduce.
• Organisms obtain food through autotrophic (producing their own food) or heterotrophic (consuming other organisms) nutrition.
• Autotrophs, such as plants and algae, use photosynthesis to convert light energy into chemical energy (glucose), using chlorophyll and water.
• Heterotrophs, which include animals and many bacteria, consume other organisms for energy and nutrients.

Nutrition

• All living organisms require food for energy, growth, and repair.
• Two primary types of nutrition are autotrophic and heterotrophic.
• Autotrophs produce their own food through photosynthesis.
• Heterotrophs obtain food by consuming other organisms.

Respiration

• Respiration is the breakdown of glucose into simpler products to release energy.
• This energy is stored as ATP (adenosine triphosphate).
• There are two types of respiration: aerobic (requires oxygen) and anaerobic (doesn't require oxygen).

Excretion

• Excretion is the removal of waste products from the body.
• These waste products are often by-products of metabolic reactions, and their removal is essential for survival.
• Gaseous exchange, sweating, and leaf shedding are examples of excretion.

Growth

• Growth is an increase in size, mass, or volume of an organism.
• It occurs through cell division and enlargement, requiring nutrients and substances.

Movement

• Movement is a change in position of an organism's body part or the whole organism.
• It can include locomotion and the movement of plant parts.
• Unicellular organisms may move using cilia or flagella, while multicellular organisms use different structures for movement.

Sensitivity

• Sensitivity is the ability of a living organism to respond to stimuli in its environment.
• Key stimuli include touch, chemicals (taste and smell), pH, light, and heat.
• Organisms respond to stimuli through receptors and sensory cells. These receptors are part of the organism's sensory organs.

Reproduction

• Reproduction is the production of new organisms.
• It ensures the continuation of a species.
• There are two types: sexual (involving the union of male and female gametes) and asexual (involving a single organism).
• Sexual reproduction creates offspring with genetic diversity.
• Asexual reproduction creates identical offspring.

Cell Structure and Function

• Cells are the basic units of life, and different cell types perform different functions.

• There are two main types of cells: prokaryotic (without a nucleus) and eukaryotic (with a nucleus).

• Both have organelles that carry out specific tasks.

• Eukaryotic cells include mitochondria, chloroplasts, vacuoles, etc., and contain DNA within a nucleus.

• Prokaryotic cells, such as bacteria, lack these internal structures, maintaining the genetic material separately.

• Cell division leads to growth, repair, and the creation of new cells.

Specialised Cells

• Organisms have specialised cells with specific shapes and functions.
• Examples include red blood cells (carrying oxygen), nerve cells (transmitting messages), muscle cells (contracting/relaxing for movement).
• Photosynthesis in plants takes place in Chloroplasts.
• Root hair cells in plants absorb water and nutrients.

Organisation

• Multicellular organisms have a complex structure with cells, tissues, organs, and organ systems.
• Tissues are groups of similar cells working together; organs are groups of tissues working together, and organ systems are groups of organs working together.
• This complex organization allows for a division of labor to complete tasks.