Sunday 28 January 2018

Section 1 a) Summary

All living organisms share the seven same basic characteristics:

Movement- the ability to move

Respiration- the ability to create chemical energy

Sensitivity- the ability to sense a change in environment

Growth- the ability to develop and mature/increase in cell size or number

Excretion- the ability to remove waste substance from the body

Nutrition- the ability to obtain nutrients

Using the acronym "MRS GREN" is an easy way to recall all of the processes.
--> read the "key words" and "specification" pages for further explanation and depth.

Each of the life processes plays a key part in ensuring the organism can live.

Movement allows the organism to adapt to avoid predators, catch prey, or produce food.

Respiration gives the organism energy and allows it to carry out all of the other life processes.

Sensitivity allows the organism to react to its surroundings, helping it survive through changes in environment such as increased temperature.

Growth allows the organism to increase in maturity and size so it can carry out other processes more efficiently, e.g. a larger plant has more leaves for photosynthesis.

Excretion allows the organism to remove waste from the body and prevent poisoning from toxic substances such as urea and carbon dioxide.

Nutrition gives the organism the nutrients required for respiration to be carried out, along with other processes such as growth.

If it carries out all of these processes, it is classified as a living organism.

Section 1 a) Key Words

Asexual reproduction: Reproduction involving one parent. The offspring produced is an exact copy, or clone, of the parent, as the DNA does not change.

Excretion: The ability to remove waste substances from the body, e.g carbon dioxide during respiration is exhaled in animals, and urination removes toxic substances such as urea from the body. Plants drop their leaves as a way of removing toxins.

Growth: The ability to increase in cell size or number as the organism matures. Baby animals grow into adults, then stop growing, but plants will continue growing throughout their whole lives.

Life processes: The seven characteristics that all living organisms share; movement, respiration, sensitivity, growth, reproduction, excretion and nutrition.

Movement: The ability to change position or move that allows them to obtain nutrients or avoid predators. Plants can move their leaves to face the sun and open and close their petals, while animals have total physical mobility; they can move their entire body from one place to another.

Nutrition: Obtaining nutrients required for life processes such as respiration through consumption of other organisms or photosynthesis. Most organisms must eat or absorb other organisms to obtain nutrients, but plants can photosynthesize- create food from sunlight.

Organisms: An individual life form that may be multi- or uni-cellular that carries out the seven life processes, e.g. plants, animals, fungi, bacteria, protoctists.

Sensitivity: The ability to sense a change in surroundings such as light, temperature, or sound, and react to it. An animal can usually react quickly to stimuli, e.g. moving away from a hot object, but plants react more slowly, e.g. growing in response to the direction of the light.

Sexual reproduction: Involving two parents, in which DNA from each of them combine to produce an individual sharing qualities from both parents.

Reproduction: The ability to produce live offspring through asexual or sexual reproduction. e.g. animals create babies, plants produce seeds. This allows the organism to carry on the existence of the species for future generations.

Respiration: The ability to produce energy from nutrients, e.g. aerobic respiration: glucose + oxygen --> carbon dioxide + water (+ energy), or anaerobic respiration: glucose --> lactic acid (+ energy). This allows the organism to carry out other processes.

Sensitivity: The ability to sense a change in the environment (a stimulus) and react to it. A plant can grow in the direction of the light, an animal can sense predator or prey and move away from it. Reflex actions happen involuntarily, e.g. reactions to temperature or sharp objects.

Section 1 a) Specification

1.1 Understand that living organisms share the following characteristics:
– they require nutrition
– they respire
– they excrete their waste
– they respond to their surroundings
– they move
– they control their internal conditions
– they reproduce
– they grow and develop. 

All species of living organisms follow the 7 life processes: MRS GREN:

M- Movement
All living organisms can move or change position. Animals have total mobility; we can walk around, lift things up, turn our heads, etc. Plants move in less obvious ways. They can turn their leaves to face the sun and open and close their flowers.

R- Respiration
All living things release energy through chemical reactions. They break down nutrients such as glucose in order to release energy and allow the organism to perform all of the other life processes.

S- Sensitivity
All living things have the ability to sense a change in their environment and react to it. E.g. A person will move their hand away from a very hot object, a plant will turn to face the sun to maximise photosynthesis.

G- Growth
All living things increase in size or cell number as the organism matures, involving chemical reactions and increase in dry mass. Animals stop growing after reaching a certain maturity, but plants continue growing until they die.

R- Reproduction
All living things have the ability to produce live offspring through sexual or asexual reproduction. Sexual reproduction involves two parents, resulting in an offspring sharing both parents' DNA and characteristics, whereas asexual reproduction involves one parent and will result in an exact copy.

E- Excretion
All living things excrete harmful or toxic chemicals within the organism, e.g carbon dioxide through gas exchange in plants and animals, and urination in animals remove urea from the body. Plants can concentrate toxins into leaves when they drop them.

N- Nutrition
All living things require nutrients for energy, growth and repair. Plants can photosynthesize to create glucose for respiration, but animals and fungi must absorb or eat other organisms to gain energy and nutrients.

Section 1: The Nature and Variety of Living Organisms Specification

a) Characteristics of living organisms

1.1 Understand that living organisms share the following characteristics:
– they require nutrition
– they respire
– they excrete their waste
– they respond to their surroundings
– they move
– they control their internal conditions
– they reproduce
– they grow and develop.

b) Variety of living organisms

1.2 describe the common features shared by organisms within the following main
groups: plants, animals, fungi, bacteria, protoctists and viruses, and for each
group describe examples and their features

1.3 recall the term ‘pathogen’ and know that pathogens may be fungi, bacteria,
protoctists or viruses.

Section 2 j) Specification

2.77 understand that organisms are able to respond to changes in their environment Organisms have receptors to detect changes in the envir...