Study Notes for Stage 1 Biology on Living and Non-Living Things

Living things are distinguishable from non-living things.
It is essential to compare the characteristics of living and non-living things to understand biological concepts.
This topic is part of the South Australian Certificate of Education (SACE).

The term ‘life’ encompasses the vast diversity of living things that inhabit the planet.
The following points address what it means to be alive and entail identifying characteristics of living organisms.

Organisms can either be unicellular (single-celled) or multicellular (multiple cells).
A living thing is defined as an organism that carries out fundamental processes associated with life, termed life processes.

Movement is utilized to find food, mates, shelter, or to evade predators.
- External Movement: Includes actions such as walking, running, swimming, flying, or sliding.
- Internal Movement: Involves the transfer of materials within cells, tissues, organs, and organ systems.
Other forms of movement:
- Plants: Respond to environmental stimuli such as temperature, humidity, and sunlight. For example, roots may grow in response to water and nutrient availability.
- Microorganisms: Bacteria and fungi move towards sources of food and water; certain bacterial species use flagella for locomotion in liquid media.

Living organisms require a continuous supply of energy, which is derived from respiration.
Respiration occurs in both unicellular and multicellular organisms and involves the breakdown of carbohydrate molecules like glucose.
Energy Storage: Energy released during respiration is stored as adenosine triphosphate (ATP).
- Aerobic Respiration: Complete breakdown of glucose in the presence of oxygen.
- Anaerobic Respiration: Partial breakdown of glucose in the absence or limited availability of oxygen.

Stimulus: Any environmental change that elicits a physiological response from the organism.
Common stimuli include variations in light intensity, heat, sound intensity/frequency, and chemical actions.
Examples include:
- Sharks detecting small electric currents generated by distressed animals from distances of several kilometers.
- Tomatoes growing towards sunlight (phototropism).
- Unicellular organisms adjusting their position in response to environmental stimuli.

Growth is characterized by processes such as cell division, which is energy-requiring.
In multicellular organisms, this involves an increase in both cell size and cell number.
Growth is vital for tissue development and repair.
In unicellular organisms, growth signifies an increase in cell numbers within a population, crucial for the continuity of the colony.

Living things reproduce to ensure the continuation of their kind. Two methods of reproduction:
- Sexual Reproduction: Involves parent organisms producing specialized cells (gametes) that combine to form a single cell, which then divides and develops. Offspring may differ genetically from parent organisms.
- Asexual Reproduction: Involves a single organism reproducing independently. Offspring are genetically identical to the parent organism.

Excretion: The process of removing metabolic wastes from the organism's body.
Metabolic processes produce toxic waste products during respiration and other cellular activities.
In unicellular organisms, waste is excreted directly into their environment through diffusion.
In multicellular organisms, specialized organs systems eliminate waste. Examples include:
- Plants: Excrete carbon dioxide (from respiration) and oxygen (from photosynthesis) via diffusion.
- Animals: Excrete carbon dioxide (from respiration), water and salts (through sweat), and urea (from metabolism). The kidneys, liver, lungs, and skin are key organs for waste removal in humans.

Organisms source, extract, process, and utilize nutrients and energy, serving as fuel for life processes.
Nutrients contribute to building larger molecules necessary for cellular function.
Animals obtain nutrients primarily through the consumption of plants and other animals. Plants convert inorganic molecules into glucose during photosynthesis.

Group Task: In small groups (pairs or three students), analyze provided cards. Identify and describe the life processes in your own words from at least six cards.
Complete the handout provided in class for further understanding.

Students are instructed to refer to Workbook: Chapter 1.1, covering Living and Non-living things.
Assignments include:
- Read pages 6-9 of the workbook.
- Answer questions on pages 10-12.