Modules 3 & 4- Evolution
Inquiry Question 1: What is the relationship between evolution and biodiversity?
3.3.1 Explain biological diversity in terms of the Theory of Evolution by Natural Selection by
examining the changes in and diversification of life since it first appeared on the Earth.
- Evolution is the process by which organisms change over time due to different selection
pressures and the changing climate.
- Evolution can be impacted by: changes in physical conditions (e.g. temperature, wind and
amount of rainfall), changes in chemical conditions (e.g. salts and pesticides), and
competition for resources (e.g. for food, space or mates).
- Charles Darwin proposed a process by which species change over time in 1858. He called
this natural selection.
Natural selection steps:
1. Variation: exists within a population
2. Selective Reproduction: those which are better adapted to their environment will survive
and reproduce
3. Inheritance: the favourable adaptations are passed onto the next generation
4. Change in population: over time, the favourable adaptations will increase in the
population (as long as the environment does not change)
Early life on Earth:
The Earth began about 4.5 billion years ago. Fossil evidence suggests that life began in the
ocean 3.8 billion years ago.
Conditions:
- Anoxic atmosphere (there was no free oxygen).
- Atmosphere had water vapour (H2O), hydrogen (H), methane (CH4) and ammonia (NH3).
- Earth’s surface was very unstable and very hot (about 1000oC).
- Many storms, meteorite impacts and erupting volcanoes which released large amounts of
ash, lava and gases.
, Geologic time scale:
3.3.2 Analyse how an accumulation of microevolutionary changes can drive evolutionary
changes and speciation over time, for example:
a) Evolution of the horse
Speciation: the evolution of a new species through the reproductive isolation of a group from the
rest of its species with no genetic interchange.
Microevolution: the small changes that occur over a short period of time in a population.
Macroevolution: the large changes that occur over a long period of time in a population.
Fossil evidence has allowed us to see evolutionary changes within the horse over millions of
years. Horses increased in size, changed teeth, and changed their toes into hooves due to the
selection pressure of their habitat changing from lush forests to dry grasslands.
Inquiry Question 1: What is the relationship between evolution and biodiversity?
3.3.1 Explain biological diversity in terms of the Theory of Evolution by Natural Selection by
examining the changes in and diversification of life since it first appeared on the Earth.
- Evolution is the process by which organisms change over time due to different selection
pressures and the changing climate.
- Evolution can be impacted by: changes in physical conditions (e.g. temperature, wind and
amount of rainfall), changes in chemical conditions (e.g. salts and pesticides), and
competition for resources (e.g. for food, space or mates).
- Charles Darwin proposed a process by which species change over time in 1858. He called
this natural selection.
Natural selection steps:
1. Variation: exists within a population
2. Selective Reproduction: those which are better adapted to their environment will survive
and reproduce
3. Inheritance: the favourable adaptations are passed onto the next generation
4. Change in population: over time, the favourable adaptations will increase in the
population (as long as the environment does not change)
Early life on Earth:
The Earth began about 4.5 billion years ago. Fossil evidence suggests that life began in the
ocean 3.8 billion years ago.
Conditions:
- Anoxic atmosphere (there was no free oxygen).
- Atmosphere had water vapour (H2O), hydrogen (H), methane (CH4) and ammonia (NH3).
- Earth’s surface was very unstable and very hot (about 1000oC).
- Many storms, meteorite impacts and erupting volcanoes which released large amounts of
ash, lava and gases.
, Geologic time scale:
3.3.2 Analyse how an accumulation of microevolutionary changes can drive evolutionary
changes and speciation over time, for example:
a) Evolution of the horse
Speciation: the evolution of a new species through the reproductive isolation of a group from the
rest of its species with no genetic interchange.
Microevolution: the small changes that occur over a short period of time in a population.
Macroevolution: the large changes that occur over a long period of time in a population.
Fossil evidence has allowed us to see evolutionary changes within the horse over millions of
years. Horses increased in size, changed teeth, and changed their toes into hooves due to the
selection pressure of their habitat changing from lush forests to dry grasslands.
