Characteristics of Living Organisms (1a)

Unit 1, The Nature and Variety of Living Organisms, a

8 Life Processes

• Movement

• Respiration

• Sensitivity

• Control

• Growth

• Reproduction

• Excretion

• Nutrition

Movement

An action caused by an organism causing a change in place or position.

• Animals: locomotion

• for food and water

• to move away from predators

• Plants: change their orientation

  • positive phototrophism

  • positive geotrophism

Respiration

Chemical reaction carried out by all living organisms to release energy from glucose in the form of ATP.

• Aerobic (with oxygen)

• Anaerobic (without oxygen)

Sensitivity

The ability to respond/react to stimuli in the surroundings

• Animals: nervous system, endocrine system

• Plants: phototropism, geotropism

Homeostasis

Controlling internal environments to keep conditions within required limits

Humans:

• Thermoregulation

• Osmoregulation

• Glucoregulation

Plants:

• Transpiration: to maintain suitable temperature

Growth

A permanent increase in size by changing the mass or number of cells

• Animals: grows larger between the zygote and adult stage with change in proportion or shape

• Plants: grows larger throughout its life with new shoots, leaves, branches, etc. forming each year

Reproduction

Process that leads to the production of more of the same kind or organism

Types:

• Asexual

• Sexual

Excretion

Removal of toxic waste products in excess of requirements

Animals

• CO₂ from respiration

• Water from respiration

• Urea (contains Nitrogen) from the breakdown of proteins

Plants

• O₂ from photosynthesis

• CO₂ from respiration

• Water from respiration and other chemical reactions

Nutrition

Organisms must obtain food to provide energy through feeding or photosynthesis

Animals

• consume other living organisms to obtain required energy

• break down larger complex molecules into simpler molecules through digestion

Plants

• use sunlight, CO₂ and H₂O to produce O₂ and glucose in the process of photosynthesis