166
tragic (probably as a result of the impact of an
asteroid) but the effects brought spectacular
changes on dry land with the complete disappearance of dinosaurs.
Despite temporary setbacks the number of
families of marine life increased by 650 from the
Cambrian to present and this growth was especially dynamic in the last 200 million years and at
the beginning of the Tertiary within it.
Terrestrial life advanced from the Silurian.
(This was enabled by the development of an
ozone layer in the stratosphere that protected life
from the dangerous effects of UV rays.) Data
regarding the increase of diversity of insects and
vertebrates are especially reliable (Fig. 4.64).
The diversity of insects started to grow rapidly as
early as 300 million years ago and this lasted to
present times except for two smaller setbacks.
The number of families of vertebrates increased
significantly in the last 100 million years although
their absolute number remained significantly
lower than that of insects.
As Homo sapiens became organised in societies a qualitative change occurred on Earth.
Humanity became capable of using any living
being to his own purposes. As mentioned above,
humanity transformed the environment of Earth
to an increasing degree in the last 10,000 years at
the expense of natural wildlife. The degree of this
impact is discussed below. Palaeontologists on
the basis of available data expressed the diversity
of the biosphere using the number of families;
however, based on indirect methods they also calculated the probable number of species.
Much more data are available for scientists
regarding biosphere at the present than in the
geological past; therefore, biological diversity
(biodiversity) can be interpreted in a number of
different ways (Box 4.8). In the present book
changes in the number of species is focused in
order to make data comparable. It has to be noted,
however, that the number of species in the biosphere has been changing dynamically in the
course of natural evolution as species were
formed and perished. Considering a long geological time span, the number of species (and
families) increased (Figs. 4.63 and 4.64).
Box 4.8 Levels of Biodiversity and the
Convention on Biological Diversity
In the most general sense biological diversity means the diversity of the biosphere.
However, it can be expressed in several
ways. A widely accepted approach is that
biological diversity (biodiversity) can be
interpreted at different levels of biological
organisation and accordingly measures
have to be made at different levels in order
to preserve it:
• population level, where the preservation
of genetic diversity and the gene reserve
is the primary goal regarding both wild
plants, animals and cultivated plants and
animals;
• species level, where the prevention of
species extinction, the termination of
the decrease of species numbers and
sustaining stable and viable populations
of individual species in adequate distribution and diversity in the long term are
the main goals;
• biocoenosis and their habitat level,
where sustaining and rehabilitation of
the species and structural diversity of
communities and their habitats are the
major tasks;
• landscape level, where the preservation
of the diversity of ecological systems
forming a natural landscape and the protection of the ecological stability of
landscapes are the major tasks.
For preserving the diversity characterised above an international convention was
accepted in Rio de Janeiro in 1992. The
fundamental aims of the convention include
the preservation of biological diversity, the
sustainable employment of its components
and the just distribution of gains obtained
from utilising the genetic resources.
This convention is not particularly a
nature protectional agreement as the terms
“sustainable employment”, “utilising
4 Changes on Earth as a Result of Interaction Between the Society and Nature
tragic (probably as a result of the impact of an
asteroid) but the effects brought spectacular
changes on dry land with the complete disappearance of dinosaurs.
Despite temporary setbacks the number of
families of marine life increased by 650 from the
Cambrian to present and this growth was especially dynamic in the last 200 million years and at
the beginning of the Tertiary within it.
Terrestrial life advanced from the Silurian.
(This was enabled by the development of an
ozone layer in the stratosphere that protected life
from the dangerous effects of UV rays.) Data
regarding the increase of diversity of insects and
vertebrates are especially reliable (Fig. 4.64).
The diversity of insects started to grow rapidly as
early as 300 million years ago and this lasted to
present times except for two smaller setbacks.
The number of families of vertebrates increased
significantly in the last 100 million years although
their absolute number remained significantly
lower than that of insects.
As Homo sapiens became organised in societies a qualitative change occurred on Earth.
Humanity became capable of using any living
being to his own purposes. As mentioned above,
humanity transformed the environment of Earth
to an increasing degree in the last 10,000 years at
the expense of natural wildlife. The degree of this
impact is discussed below. Palaeontologists on
the basis of available data expressed the diversity
of the biosphere using the number of families;
however, based on indirect methods they also calculated the probable number of species.
Much more data are available for scientists
regarding biosphere at the present than in the
geological past; therefore, biological diversity
(biodiversity) can be interpreted in a number of
different ways (Box 4.8). In the present book
changes in the number of species is focused in
order to make data comparable. It has to be noted,
however, that the number of species in the biosphere has been changing dynamically in the
course of natural evolution as species were
formed and perished. Considering a long geological time span, the number of species (and
families) increased (Figs. 4.63 and 4.64).
Box 4.8 Levels of Biodiversity and the
Convention on Biological Diversity
In the most general sense biological diversity means the diversity of the biosphere.
However, it can be expressed in several
ways. A widely accepted approach is that
biological diversity (biodiversity) can be
interpreted at different levels of biological
organisation and accordingly measures
have to be made at different levels in order
to preserve it:
• population level, where the preservation
of genetic diversity and the gene reserve
is the primary goal regarding both wild
plants, animals and cultivated plants and
animals;
• species level, where the prevention of
species extinction, the termination of
the decrease of species numbers and
sustaining stable and viable populations
of individual species in adequate distribution and diversity in the long term are
the main goals;
• biocoenosis and their habitat level,
where sustaining and rehabilitation of
the species and structural diversity of
communities and their habitats are the
major tasks;
• landscape level, where the preservation
of the diversity of ecological systems
forming a natural landscape and the protection of the ecological stability of
landscapes are the major tasks.
For preserving the diversity characterised above an international convention was
accepted in Rio de Janeiro in 1992. The
fundamental aims of the convention include
the preservation of biological diversity, the
sustainable employment of its components
and the just distribution of gains obtained
from utilising the genetic resources.
This convention is not particularly a
nature protectional agreement as the terms
“sustainable employment”, “utilising
4 Changes on Earth as a Result of Interaction Between the Society and Nature