summary buiteNLand Chapter 2 // 3 havo TTO
2.1 - The face of the Earth is changing
the origin of the earth
When the earth came into existence, it was glowing hot and molten, the
earth slowly cooled and the Earth’s core, mantle and crust were formed. As a
result of the volcanic activity, water vapor and CO2 enters the atmosphere. a
large part of the water vapor condensed into water, which is now largely in
the oceans. Slowly the conditions became suitable for living organisms.
about three billion years ago, bacteria formed that absorbed CO2 from the
atmosphere and released oxygen. This oxygen created possibilities for more
complex life forms.
the geological history
at first life only consisted of bacteria, but slowly new life forms emerged.
molluscs, fish, land plants, reptiles etc. the geological time scale has four
main era’s:
- precambrian: Continents appeared and the earth froze. there was only
life under water. At the end of this era the first forms of life on the land
was created.
- palaeozoic: the continents first moved apart, but later merged into
supercontinent pangea.
- Mesozoic: this era is known as the time of the dinosaurs. pangea
started breaking apart and the current continents were formed.
- Cenozoic: the area after the dinosaurs died out, life comes to being as
we know it now, with man at the end.
a coming and going of species
a large part of all life on earth disappeared five times. The causes for these
mass extinctions are unclear. It is assumed that at the last mass extinction,
about 65 million years ago, a large meteorite caused a lot of dust in the
atmosphere.
, 2.2 - The history of the earth
rocks and fossils
a fossil is a fossilized remain of (part of) a skeleton, or an imprint
of an animal or plant. rocks and fossils provide a lot of
information about the conditions and climate of the past. For
example, a fossil of a mammoth at the bottom of the north sea,
indicates that there was a colder climate there in the past and
where the north sea is now, there used to be land. ammonites
are index (or trace) fossils. They lived in a large area for a short
time. the shorter a certain species lived the more precisely a rock
layer can be dated.
stacked up time
there are three types of rocks:
1. sedimentary rock: rock that is made up of layers of sand and clay that
were deposited over each other. The loose particles harden into rock by
pressure from the upper layers. examples are sandstone and limestone
2. igneous rock: this rock is created by cooling magma. examples are
granite and quartz
3. metamorphic rock: this rock has changed due to high pressure and
high temperature. an example is marble that originates from limestone
relative and absolute time
if you look at the picture on the side, you don’t know
when these layers were formed. but you do know in
what order they originated. We call that relative age,
the age in relation to each other. Some rocks contain
very small amounts of radioactive elements such as
uranium. radioactive material deteriorates at a fixed
speed, so you can calculate how old the rock is. this is
called absolute age
2.1 - The face of the Earth is changing
the origin of the earth
When the earth came into existence, it was glowing hot and molten, the
earth slowly cooled and the Earth’s core, mantle and crust were formed. As a
result of the volcanic activity, water vapor and CO2 enters the atmosphere. a
large part of the water vapor condensed into water, which is now largely in
the oceans. Slowly the conditions became suitable for living organisms.
about three billion years ago, bacteria formed that absorbed CO2 from the
atmosphere and released oxygen. This oxygen created possibilities for more
complex life forms.
the geological history
at first life only consisted of bacteria, but slowly new life forms emerged.
molluscs, fish, land plants, reptiles etc. the geological time scale has four
main era’s:
- precambrian: Continents appeared and the earth froze. there was only
life under water. At the end of this era the first forms of life on the land
was created.
- palaeozoic: the continents first moved apart, but later merged into
supercontinent pangea.
- Mesozoic: this era is known as the time of the dinosaurs. pangea
started breaking apart and the current continents were formed.
- Cenozoic: the area after the dinosaurs died out, life comes to being as
we know it now, with man at the end.
a coming and going of species
a large part of all life on earth disappeared five times. The causes for these
mass extinctions are unclear. It is assumed that at the last mass extinction,
about 65 million years ago, a large meteorite caused a lot of dust in the
atmosphere.
, 2.2 - The history of the earth
rocks and fossils
a fossil is a fossilized remain of (part of) a skeleton, or an imprint
of an animal or plant. rocks and fossils provide a lot of
information about the conditions and climate of the past. For
example, a fossil of a mammoth at the bottom of the north sea,
indicates that there was a colder climate there in the past and
where the north sea is now, there used to be land. ammonites
are index (or trace) fossils. They lived in a large area for a short
time. the shorter a certain species lived the more precisely a rock
layer can be dated.
stacked up time
there are three types of rocks:
1. sedimentary rock: rock that is made up of layers of sand and clay that
were deposited over each other. The loose particles harden into rock by
pressure from the upper layers. examples are sandstone and limestone
2. igneous rock: this rock is created by cooling magma. examples are
granite and quartz
3. metamorphic rock: this rock has changed due to high pressure and
high temperature. an example is marble that originates from limestone
relative and absolute time
if you look at the picture on the side, you don’t know
when these layers were formed. but you do know in
what order they originated. We call that relative age,
the age in relation to each other. Some rocks contain
very small amounts of radioactive elements such as
uranium. radioactive material deteriorates at a fixed
speed, so you can calculate how old the rock is. this is
called absolute age
