Summary Biology Chapter 4
4.1 What is a species?
Species is a group of organisms with the same characteristics that can breed together and have
fertile offspring.
o An apple and pear do not belong to the same specie.
o Cats all look a bit different, but they are all one specie.
A lot of species look a bit different from each other.
In a specie, there are different breeds (subspecies), they have different characteristics (a
different breed cow may be able to produce more mild) but still belong to the same specie.
In biology, there are four kingdoms: Bacteria, Fungi, Plants &
Animals
We subdivide organisms even more: first the kingdoms, then into
phylum, then into class, then into order, then into family and
finally into genus.
Closely related species form a genus (genera pl)
Each organism has two Latin names. The first name is the generic
name (with a capital letter)
The second name is the specific name (lowercase letter)
The way is called binary nomenclature)
A fox is named Vulpes vulpes for example.
The person who invented this system was named Carolus
Linnaeus, and published this in his book called Systema naturae.
4.2 What is evolution?
o Almost all plants and animals (and all of their characteristics) are
perfectly adapted to their environment and their way of life.
o These changes are the result of a very long process called evolution.
o The variation in appearance of animals is called the fist symptom in explaining evolution. The
second symptom is that more organisms are born in nature than there is space or food for.
o Plants and animals have to compete for space and food. The plants and animals are
often also food for other animal species: only a small percentage of babies will mature.
o A frog lays about 2500 eggs, but only 3 survive. This describes the third symptom: all plants and
animals have a risky life with a lot of competition and dangers.
o At one point, a super frog is born. This frog can swim a little faster, making it easier to escape
from predators. When this super frog will survive, it will start to reproduce.
o The characteristic of being able to a little faster is hereditary and is passed on to its children who
will all be able to swim a little faster.
o Eventually, every frog will swim faster: the fourth symptom, a characteristic that offers an
advantage will, after a long time, dominate a large part of the species through inheritance.
, The four symptoms of evolution are thus:
- Variation within a species
- Many offspring
- Fierce competition in nature
- Inheritance of favorable characteristics
o The variation within a species is pure coincidence
o The process in nature which the best candidates are selected, is
called natural selection.
o If a species has a variation in characteristics that make them
survive better, they will survive better and become the majority
of the species.
o Natural selection does not necessarily mean a new species. Only when the two groups of the
same species are separated for a long time, they do not recognize each other as the same specie
anymore.
o Biologists call a group of animals of the same species in a certain area a population. Isolation
from a part of the population plays an important role in evolution.
o On the Galapagos islands, there are more than 10 different species of finches. They were
separated and become specialized in the type of food they found.
o The finches became so different from each other, that they no longer recognized each other:
they became a different species.
4.3 The history of life
Evolution takes a lot of time, often a scale of millions of years.
Men (Homo sapiens) originated around 250,000 years ago.
The chimpanzee is most closely related to humans.
o Man and the chimpanzee had a common ancestor which lived between 4 and 6 million
years ago.
All organisms on earth have one common ancestor, which lived about 3,800 million years ago, it
was single-celled and were part of the Bacteria Kingdom.
The earth’s age can be determined using the earth’s layers. Scientists who do this are called
geologists, the time scale they use is the geological time scale.
The four major periods in earth history are the Precambrian, the Paleozoic, the Mesozoic & the
Cenozoic.
4.1 What is a species?
Species is a group of organisms with the same characteristics that can breed together and have
fertile offspring.
o An apple and pear do not belong to the same specie.
o Cats all look a bit different, but they are all one specie.
A lot of species look a bit different from each other.
In a specie, there are different breeds (subspecies), they have different characteristics (a
different breed cow may be able to produce more mild) but still belong to the same specie.
In biology, there are four kingdoms: Bacteria, Fungi, Plants &
Animals
We subdivide organisms even more: first the kingdoms, then into
phylum, then into class, then into order, then into family and
finally into genus.
Closely related species form a genus (genera pl)
Each organism has two Latin names. The first name is the generic
name (with a capital letter)
The second name is the specific name (lowercase letter)
The way is called binary nomenclature)
A fox is named Vulpes vulpes for example.
The person who invented this system was named Carolus
Linnaeus, and published this in his book called Systema naturae.
4.2 What is evolution?
o Almost all plants and animals (and all of their characteristics) are
perfectly adapted to their environment and their way of life.
o These changes are the result of a very long process called evolution.
o The variation in appearance of animals is called the fist symptom in explaining evolution. The
second symptom is that more organisms are born in nature than there is space or food for.
o Plants and animals have to compete for space and food. The plants and animals are
often also food for other animal species: only a small percentage of babies will mature.
o A frog lays about 2500 eggs, but only 3 survive. This describes the third symptom: all plants and
animals have a risky life with a lot of competition and dangers.
o At one point, a super frog is born. This frog can swim a little faster, making it easier to escape
from predators. When this super frog will survive, it will start to reproduce.
o The characteristic of being able to a little faster is hereditary and is passed on to its children who
will all be able to swim a little faster.
o Eventually, every frog will swim faster: the fourth symptom, a characteristic that offers an
advantage will, after a long time, dominate a large part of the species through inheritance.
, The four symptoms of evolution are thus:
- Variation within a species
- Many offspring
- Fierce competition in nature
- Inheritance of favorable characteristics
o The variation within a species is pure coincidence
o The process in nature which the best candidates are selected, is
called natural selection.
o If a species has a variation in characteristics that make them
survive better, they will survive better and become the majority
of the species.
o Natural selection does not necessarily mean a new species. Only when the two groups of the
same species are separated for a long time, they do not recognize each other as the same specie
anymore.
o Biologists call a group of animals of the same species in a certain area a population. Isolation
from a part of the population plays an important role in evolution.
o On the Galapagos islands, there are more than 10 different species of finches. They were
separated and become specialized in the type of food they found.
o The finches became so different from each other, that they no longer recognized each other:
they became a different species.
4.3 The history of life
Evolution takes a lot of time, often a scale of millions of years.
Men (Homo sapiens) originated around 250,000 years ago.
The chimpanzee is most closely related to humans.
o Man and the chimpanzee had a common ancestor which lived between 4 and 6 million
years ago.
All organisms on earth have one common ancestor, which lived about 3,800 million years ago, it
was single-celled and were part of the Bacteria Kingdom.
The earth’s age can be determined using the earth’s layers. Scientists who do this are called
geologists, the time scale they use is the geological time scale.
The four major periods in earth history are the Precambrian, the Paleozoic, the Mesozoic & the
Cenozoic.
