§7.1; How it all began
Mutations can be negative, but they can also be neutral or sometimes even beneficial. These mutations
are caused because of evolution. Darwin found out about evolution when he found rocks on top of a
mountain and then he realized that the top of the mountain once had been in the sea.
Darwin found on the Galapagos island that the species there looked different to the species on the
mainland, but were also similar in a way. He also noticed that on each island the species had a
different type of diet, fourteen different finch species had the same ancestor, but evolved to fit better
in their environment. The more successful the individual, the longer it survives and more offspring it
can produce, this is called differential reproduction.
Breeding organisms with a specific characteristic, to get the desired characteristics is called artificial
selection. Unsuccessful individuals will reproduce less often as successful individuals. Adaptation is
essential for species to survive in the changing ecosystem.
Structural adaptations are evolutionary changes in body parts. Rats may have gotten claws and are
now mole-rats. If a species changes color in order to camouflage then it's called mimicry.
Physiological adaptations (evolutionary changes in the chemical process inside the cells if an
organism) happen much faster. For instance, if you use antibiotics after a while they won't work as
good, because the bacteria become resistant to antibiotics.
An example of natural selection is when the food species eat is high in the trees, the taller species will
survive. They pass on these genetics more easily, because they can reproduce more often.
§7.2; Evidence for evolution
Homologous structures are similar structures in the arrangement of bones in different species. Similar
structures don't always mean that species are closely related. When body structures don't have a
common evolutionary origin, but do have the same function, it’s called analogous structures. All the
different structures together are called anatomical structures.
Vestigial structures are structures that aren’t used anymore / doesn’t serve its original service.
Examples are: a tail, muscles in ears, muscles attached to hair follicle. In furred mammals these
muscles make their hair stand upright. However, humans just get goosebumps.
Scientists thought that the appendix was useless after you’re born when it was used to digest
cellulose. However, it contains immune system cells, so it’s not a vestigial structure.
§7.3; What about fossils…
When an organism dies, it turns into a fossil, at a fish this process can be: first it sinks to the
bottom of the ocean → soft body parts decay and are eaten away → the fish becomes covered with
sand and mud → only the skeleton is left which is covered with lots of layers of mud → the bones
decay too, the space that was filled with bones is now filled with mineral deposits → it forms a
stone cast → the layers of rock and mud are lifted due to movements of the Earths crust → a part
of the rock eroses away and that leaves the skull of the fish exposed.
Mutations can be negative, but they can also be neutral or sometimes even beneficial. These mutations
are caused because of evolution. Darwin found out about evolution when he found rocks on top of a
mountain and then he realized that the top of the mountain once had been in the sea.
Darwin found on the Galapagos island that the species there looked different to the species on the
mainland, but were also similar in a way. He also noticed that on each island the species had a
different type of diet, fourteen different finch species had the same ancestor, but evolved to fit better
in their environment. The more successful the individual, the longer it survives and more offspring it
can produce, this is called differential reproduction.
Breeding organisms with a specific characteristic, to get the desired characteristics is called artificial
selection. Unsuccessful individuals will reproduce less often as successful individuals. Adaptation is
essential for species to survive in the changing ecosystem.
Structural adaptations are evolutionary changes in body parts. Rats may have gotten claws and are
now mole-rats. If a species changes color in order to camouflage then it's called mimicry.
Physiological adaptations (evolutionary changes in the chemical process inside the cells if an
organism) happen much faster. For instance, if you use antibiotics after a while they won't work as
good, because the bacteria become resistant to antibiotics.
An example of natural selection is when the food species eat is high in the trees, the taller species will
survive. They pass on these genetics more easily, because they can reproduce more often.
§7.2; Evidence for evolution
Homologous structures are similar structures in the arrangement of bones in different species. Similar
structures don't always mean that species are closely related. When body structures don't have a
common evolutionary origin, but do have the same function, it’s called analogous structures. All the
different structures together are called anatomical structures.
Vestigial structures are structures that aren’t used anymore / doesn’t serve its original service.
Examples are: a tail, muscles in ears, muscles attached to hair follicle. In furred mammals these
muscles make their hair stand upright. However, humans just get goosebumps.
Scientists thought that the appendix was useless after you’re born when it was used to digest
cellulose. However, it contains immune system cells, so it’s not a vestigial structure.
§7.3; What about fossils…
When an organism dies, it turns into a fossil, at a fish this process can be: first it sinks to the
bottom of the ocean → soft body parts decay and are eaten away → the fish becomes covered with
sand and mud → only the skeleton is left which is covered with lots of layers of mud → the bones
decay too, the space that was filled with bones is now filled with mineral deposits → it forms a
stone cast → the layers of rock and mud are lifted due to movements of the Earths crust → a part
of the rock eroses away and that leaves the skull of the fish exposed.
