Microbial Diversity

Describe 3 features of populations that experience Darwinian evolution

Multiplication: Specific traits can enable an individual to survive longer or reproduce more than others, so over time these traits become more common in the population leading to evolutionary change.

Heredity: Traits must be heritable otherwise they cannot be passed on through the generations.

Variation: Individuals have different traits which is crucial as it provides the material for natural selection to act upon.

Explain what conditions were like on Earth before the evolution of life.

Lots of rock and volcanos, Earth was hotter due to volcanic activity. Lack of O2 in the atmosphere making it toxic to aerobic organisms, lots of CO2. Water vapor which created the first oceans. RNA world.

Elaborate on ‘RNA world’

There were no enzymes or DNA. RNA was used as catalysts driving chemical reactions before enzymes. Used to store genetic information before DNA. DNA is a mutation of RNA that overtook as the information storing molecule as it’s more stable.

Describe the evidence that suggests the approximate time that microbial life evolved

Stromatolites (fossilized mats) containing ancient prokaryotes that date back 3.5bya proving fossil evidence of early life.

Carbon isotopes, suggest biological activity that dates back to around 3.85bya.

Compare and contrast the physical structure of Prokaryotes and Eukaryotes

Prokaryotes: No nucleus, no membrane-bound organelles, generally smaller, cell division by binary fission, cell wall made of peptidoglycan. Shapes can be spherical, rod-shaped or spiral. Bacteria and Archae.

Eukaryotes: True nucleus surrounded by nuclear membrane, generally larger, has membrane-bound organelles, cell division by meiosis or mitosis. Animals, plants, fungi, protists.