Section 1 b) Summary

Living organisms are organised into categories based on shared characteristics. The seven taxonomic groups of classification are:

• Kingdom (e.g. Animalia)
• Phylum (e.g. Chordata)
• Class (e.g. Mammalia)
• Order (e.g. Carnivora)
• Family (e.g. Canidae)
• Genus (e.g. Canis)
• Species (e.g. Lupus)

Species are internationally known by their binomial classification, which is a two-part latin name composed of species and genus used to identify groups of organisms that share similar characteristics and are able to breed to produce fertile offspring. In the above example, the species would be known as Canis Lupus (Grey Wolf). 

All living organisms fall under the five kingdoms of classification: Animals, plants, bacteria, fungi and protoctists. Each of these groups is defined by their own set of characteristics:

Animals
Multi-cellular, No cell walls, No chloroplasts = No photosynthesis, therefore they must consume other organisms to gain energy. Cells move freely.

Can move their entire body due to nervous system.
Glycogen - how animals store carbohydrates
Vertebrates are animals with spines/backbones
Invertebrates are animals without spines/backbones

Vertebrates can be split into the following categories:

• Mammals (warm-blooded, secrete milk, give birth to live young, have lungs, most have hair)
• Birds (warm-blooded, feathers, wings, beaks, hard shelled eggs, have lungs)
• Fish (cold-blooded, jelly-coated eggs laid in water, scales, fins and gills)
• Reptiles (cold-blooded, leathery-shelled eggs, scales, have lungs)
• Amphibians (cold-blooded, jelly-coated eggs laid in water, moist skin, gills when young, lungs when mature)

E.g. Cat, Dolphin, Owl, Chicken, Cod, Haddock, Adder, Blue-tongue Lizard, Salamander, Frog

Plants
Multi-cellular, Cellulose cell walls, Chloroplasts for photosynthesis, absorb water through their roots and up the xylem vessel by osmosis.

Move leaves etc. to face the sun
Starch or Sucrose - how plants store carbohydrates
Carnivorous plants: some plants adapt to nutrient-poor soil by attracting, trapping and digesting insects or small animals to gain nutrients from them.

E.g. Sunflower, Cacti, Oak, Yew, Palm

Bacteria
Uni-cellular, No Nucleus (Plasmid and DNA loop instead), Polysaccharide or Protein cell wall, some have Chloroplasts, all have Mesosomes

Some have flagellum for free movement
Glycogen or Lipid food stores

E.g. Lactobacillus Bulgaricus, Pneumococcus, Escherichia Coli (E.Coli), Salmonella

Fungi
Multi- or uni-cellular, Chitin cell walls, organised in fungal hyphal structures with threads/fibres called hyphae, which organise into mycelium.

Fungi feed through saprotrophic nutrition, also known as extracellular digestion. The cells secrete digestive enzymes to break down organic matter, which is then absorbed by the fungus.
Glycogen- how carbohydrates are stored in fungi

E.g. Yeast (uni-cellular), Mucor (multi-cellular)

Protoctists
Uni-cellular, characteristics vary: some resemble animal cells, some resemble plant cells, some are pathogenic

E.g. Amoeba, Plasmodium, Chlorella

Viruses are not classified as living organisms, they are a special case; they don't perform all seven life functions, and they can only reproduce inside a living cell. They are parasitic and pathogenic.

E.g. Human Immunodeficiency Virus (H.I.V), Influenza, Tobacco Mosaic Virus



Pathogens
A pathogen is a disease-causing particle or organism. It infects a living organism and inhibits their normal function. Pathogens can be viruses, bacteria, protoctists or fungi.

Section 1 b) Specification

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

The five kingdoms of classification are plants, animals, fungi, bacteria and protoctists. Viruses are not classified as living organisms, but they are a special case (they can carry out all of the functions of living organisms within a living cell)

Animals (Animalia) are multi-cellular organisms that need to feed off other living organisms as they do not contain chloroplasts for photosynthesis. Animal cells have no cell walls and are able to move freely. Animals are able to move their entire body due to their nervous system. They store carbohydrates as glycogen in their muscles.
Examples include: Humans, Fish, Bumble Bees, Chicken, Tortoises, etc.

Plants (Plantae) are multi-cellular organisms that contain chloroplasts to produce food through photosynthesis. They have cellulose cell walls, that provide the plant with structure and support, and they store carbohydrates as starch or sucrose. Carnivorous plants such as the venus flytrap are able to catch and digest small animals in order to obtain nutrients in poor soil.
Examples include: Rice, Sunflowers, Bananas, Beans, Roses, Wheat, etc.

Protoctists (Protoctista), also known as the 'dustbin kingdom', are a kingdom of greatly varied uni-cellular organisms. Some have characteristics of animal cells, some photosynthesize like plant cells, and some are pathogenic.
Examples include: Chlorella, Amoeba, Plasmodium, Euglena, Paramecium, etc.

Fungi (Fungus) can be multi- or uni-cellular. They cannot photosynthesize, so they must feed off other organisms. They do this through saprotrophic nutrition, the secretion of digestive enzymes into the surrounding environment to break down nutrients the fungus will then absorb the broken-down organic matter (this is also known as extracellular digestion, it happens outside the cell). Their bodies are organised in a fungal hyphal structure: they look like threads called 'hyphae', which are organised in mycelium. They have chitin cell walls and store carbohydrates as glycogen.
Examples include: Yeast (uni-cellular), Mucor, Basidiomycota, etc.

Bacteria (Prokaryotes) are uni-cellular organisms without a nucleus, instead containing a loop of DNA and a plasmid, which can move between cells. They have polysaccharide or protein cell walls, glycogen or lipid food stores and mesosomes for respiration. Some have flagellum to allow them to move, or chlorophyll to carry out photosynthesis (however most feed off other living organisms)
Examples include: Pneumococcus, Lactobacillus bulgaricus (used to make yoghurt), E.Coli, etc.

Viruses are much smaller than bacteria, and all are parasitic. They can only reproduce inside living cells, and don't carry out all of the seven life processes. Viruses are made up of genetic material and a protein coat. All viruses are pathogenic, disease-causing.
Examples include: Influenza, Human Immunodeficiency Virus (HIV), Tobacco Mosaic Virus, etc.

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

A pathogen is a disease-causing micro-organism. Pathogens include bacteria, viruses, fungi and protoctists.
Examples of pathogens:

• E.Coli (Bacterium)
• Influenza (Virus)
• Candida (Fungus)
• Pneumococcus (Bacterium)
• HIV (Virus)
• Cryptococcus (Fungus that causes meningitis)

Section 1 b) Key Words

Amphibians: Cold-blooded vertebrates that are semiterrestrial and oviparous. Their young are typically aqueous with gills.

Animals: A multicellular organism that feeds off other living organisms. Their cells have no cell walls, and they have a nervous system so they can move their whole bodies freely.

Bacteria: Unicellular organisms without nuclei, they have a loop of DNA and a plasmid instead. They have a cell wall and some contain chlorophyll for photosynthesis.

Birds: A class of warm-blooded oviparous veterbrates with feathers, a beak, and wings.

Binomial Classification: A internationally accepted two-part classification of species made up of genus and species.

Class: A taxonomic group between phylum and order

Classification: A way of grouping organisms based on their similarities. There are 7 levels of classification.

Family: A taxonomic group between genus and order

Fish: A cold-blooded oviparous class of animals that are vertebrates and have gills to breathe in water.

Fungi: Multi- or uni-cellular organisms, typically organised in fungal hyphal structures. They have chitin cell walls and secrete enzymes for extracellular saprotrophic nutrition

Genus: A taxonomic group between species and family

Invertebrates: Animals without a backbone

Kingdom: The highest taxonomic group - there are 5 kingdoms e.g. Animalia, plantae, protoctista

Mammals: A class of warm-blooded animals that are vertebrates and give birth to live young.

Multicellular: An organism made up of more than one cell

Order: A taxonomic group between class and family

Organisms: An individual living thing that carries out the seven life processes

Phylum: A taxonomic group between kingdom and class

Plants: Multicellular organism with chloroplasts for photosynthesis (produces its own food). They have cellulose cell walls and store carbohydrates as starch or sucrose.

Prokaryotes: Another name for the bacteria kingdom

Protoctists: Uni-cellular organisms that vary greatly in all other characteristics, they can be pathogenic (e.g. plasmodium which causes malaria) and can share characteristics with other kingdoms

Reptiles: A cold-blooded oviparous vertebrate that breathes through lungs and is covered in dry scales or plates

Species: A group of closely related organisms that are able to interbreed and produce live young. The fundamental category of taxonomic classification.

Unicellular: A single-celled organism

Vertebrates: Animals with a backbone

Viruses: Parasites that can only reproduce inside living cells. They are not classified as living organisms, they are a strand of genetic material surrounded by a protein coat.

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.