UNIT 6. LIVING

THINGS/BIOSPHERE Designed by Juan Gabriel 1B2

1. WHAT DO ALL LIVING THING HAVE IN

COMMON?

� 1. ALL LIVING THINGS CARRY OUT THREE FUNCTIONS:

� NUTRITION: Refers to all process which enable living things to obtain the energy and matter they need to live. Living thing can be classified into two groups depending on how they feed.

� Autotrophs: produce the organic substances (glucides, lipid, proteins…) which they need from inorganic substances (water, mineral salt, carbon dioxide) by the process of photosynthesis.

� Heterotrophs: feed on organic matter which is already elaborated. Can be: herbivores, carnivores, omnivores, saprohytes

� INTERACTION WITH THE ENVIROMENT: All the processes which enable living things to react to changes in the environment.

� REPRODUCTION: refers to all the processes which enable living thing to create new living thing. There are two basic types:

� Asexual reproduction: involve one living thing.

� Sexual reproduction: involves living things of different sexes. Each one provide a sex cell or gamete. The two cells join to form the first cell of a new living thing, the zygote.

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1. WHAT DO ALL LIVING THING HAVE IN

COMMON?

� 2. ALL LIVING THINGS HAVE A SIMILAR CHEMICAL COMPOSITION:

� All living thing are made up of chemical substances: Carbon (C ), oxygen (O), hydrogen (H) and nitrogen (N) make up about 95% off all living matter. Combination of these elements form molecules of living matter called biomolecules.

� Living thing are made up of two kinds of substances:

� ORGANIC SUBSTANCES: They are exclusive to living beings. There are four types:

BIOMOLECULE EXAMPLE USE/FUNCTIONS

GLUCIDE Glucose

Cellulose

To provide energy

To make structures

LIPIDS Fatty acids

Cholesterol

To provide energy

To make structures

PROTEINS Heamoglobin

Antibodies

Queratine

To transport oxygen

To fight microorganisms that cause diseases

To make structures: hair, nails…

NUCLEIC ACID DNA

RNA

To control cell function and heredity

1. WHAT DO ALL LIVING THING HAVE IN

COMMON?

� 2. ALL LIVING THINGS HAVE A SIMILAR CHEMICAL COMPOSITION:

� Inorganic substances: They are compounds that are not exclusive to living beings;

however, they are essential for life.

� Water is the most abundant substance in living beings (about 65 % of the body). It

is needed to transport substances and to regulate body temperature.

� Mineral salts form the solid structure of living beings such as skeletons. They are

also involved in chemical reactions and in the transmission of nervous impulses.

� 3. ALL LIVING THINGS ARE MADE UP OF CELLS

2. WHAT ARE CELLS?

� CELL ARE THE SMALEST UNIT OF LIFE. THEY ARE THE STRUCTURAL AND

FUNCTIONAL UNIT FOR ALL LIVING THINGS.

� CELLULAR THEORY

� All living things are made up of one (unicellular) or more cells (pluricellular)

� Cell carry out the functions of nutrition, interaction with their environment and

reproduction.

� All cell come from other cells.

2. WHAT ARE CELLS?

� PARTS OF A CELL

� Cells have three main parts:

� CELL MEMBRANE: is a thin layer that surround and protect the whole cell. It regulates

which substances enter and exit the cell

� CYTOPLASM: is the inside of the cell. It is a jelly-like substance. Many of the chemical

reactions of the cell take place here. Organelles are small structures in the cytoplasm,

which are responsible for cell functions.

� GENETIC MATERIAL: controls and regulates how cells work. This DNA contains the

hereditary information that is passed from one cell to the daughter cells.

Organelles:

2. WHAT ARE CELLS?

� TYPES OF CELL

� PROKARYOTIC CELLS: Don´t have nucleus, don´t have nuclear membrane. Genetic

material is disperses through the cytoplasm. They are simpler and smaller than

eukaryotic cells. Bacteria are made up of prokaryotic cells.

� EUKARYOTIC CELLS: Have a nucleus, separated from the cytoplasm by the nuclear

membrane. Algae, protozoa, fungi animals and plants have eukaryotic cells. There are

two types of eukaryotic cells: animal and plant. There are some differences between

animal and plant cells:

� Plant cells have a rigid cell wall which surrounds the plasmatic membrane. The cell wall gives the cell

its shape and strengthens it.

� Plant cells are usually polyhedral, but animal cells are various shapes: round, square, star-like.

� Plant cells have unique organelles called chloroplast which are responsible for photosynthesis.

� The nucleus of plants cells is usually found on one side. A vacuole takes up most of the space. Animal

cells also have vacuoles, but they are smaller.

2. WHAT ARE CELLS?

� TYPES OF CELL

3. THE ORGANISATION OF ORGANISMS

� Living things can be classified into two different groups:

� Unicellular: living thing have only one cell. They sometimes form colonies.

Unicellular living thing feed, interact with the environment and reproduce.

Example: paramecia.

� Multicellular: living thing have many different cells. Example: plants and animals.

Cells in multicellular living things are organised in levels.

� Cells: are specialised: they have specific functions. Each type has a unique

shape and structure. Example: blood cells, muscle cell, neurons…

� Tissues: are group of cells with the same functions. Example: muscle tissue,

epithelium…

� Organs: are group of various tissues which act together. Example: heart,

stomach, muscle, lung…

� Systems: are made up of several organs. Example: digestive system, respiratory

system, circulatory system, muscular system

3. THE ORGANISATION OF ORGANISMS

4. WHAT ARE THE FIVE KINGDOMS?

� Scientific classify all living thing into five kingdoms by four main criteria:

type of cells, number of cells, how these cells are grouped and nutrition.

4. WHAT ARE THE FIVE KINGDOMS?

� Each kingdom is divided into subgroups in order to classify organism.

� This is how you are classified.

5. WHAT IS A SPECIES?

� A specie is the first level of classification for living things.

� A specie is a set of living thing which are physically similar, they can

reproduce and have fertile descendants.

5. WHAT IS A SPECIES?

� Animal from the same species have similar appearances. However, there can

be differences in structure, size and colouring between the male and the

female. This difference is called sexual dimorphism.

6. WHAT IS BIODIVERSITY?

� Biodiversity is the variety of life on Earth.

� Biodiversity is the result of a slow process called evolution. Evolution began with the first life forms and still continues today. Species change and adapt to the environment.

� Biodiversity varies tremendously throughout the world. It is influenced by climate zones and habitats.

� WHAT FACTORS CAN REDUCE BIODIVERSITY?

� Destruction of habitats caused by deforestation, the construction of road, dams, etc.

� Uncontrolled hunting and fishing.

� Pollution of water soil and the atmosphere.

� Introduction of exotic species.

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