Evolution - Topic 1 Flashcards
What were the ideas on the way life worked during the 1800s based on?
Mechanism. The forces of physics and chemistry can be applied to understand how life works
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What did Descartes think about how physical actions are made?
R Descartes. (1596-1650) - the interaction of our senses and the world (sensors and stimuli) produce actions (effector).
What is life?
Living organisms use energy (metabolise) to grow and reproduce. It also involves a process of inheritance and change.
Life uses energy to increase local order (reduce entropy)
Scott, topics 2, 3
What are the two theories on the origin of life?
RNA World and the Metabolism first theories
What environment did life emerge in in the metabolism first theory? Give an example
In extreme environment like the deep ocean floor.
How were the molecular characteristics of life made through the metabolism first theory?
Prebiotic chemicals emerged from the cracks in the earth’s crust, interacting with sea water forming precursor organic molecules on high concentration. Their chemical reactions pricked the energy needed for life to function. They would have the ability to self assemble, aytocatalyse, self replicate and form cell membranes.
What environment did life emerge in in the RNA world theory?
In BENIGN conditions of a deep-sea hydrothermal vent where chemical gradients may have allowed metabolic processes to emerge.
How does the RNA world theory work?
RNA can store and transfer genetic information, act as a catalyst, organise itself and self replicate.
It formed when single prebiotic molecules became concentrated, forming nuclear acid monomers and eventually polymers (like RNA)
That led to:
reduced diversity of products, amplification of small differences and stability of biopolymers and self assembled structures.
The polymers catalyse polymerisation of the monomers and allow direct assembly of copies, producing macromolecules.
Why was RNA selected for in the RNA world theory?
It was selected for replication because it provides better structural support meaning living cells were more likely to be formed from it. - RNA co-opted proteins and formed cells.
It can also catalyse its own replication (essential for lifes need to reproduce)
