Lecture 1 - Introduction to the module & evolution Flashcards
(14 cards)
What 2 problems did Charles Darwin solve in his book - “Origin of species”
- The problem of history
- The problem of design
What is an example of the problem of history where evolution only tweaks existing structures?
A human arm, a bat wing, and a horse leg all contain a humerus, ulna and metacarpals - yet all are different shapes and serve different purposes
What is a molecular level example of the problem of history?
Cytochrome C (a protein molecule)
Similarity of the protein between humans and Rhesus monkeys - around 103 similarities
The more similar animals look, the more similair the structure of Cytochrome C
What is the problem of design?
That species look like they are perfectly designed and well adapted for their surroundings - i.e fennec fox in summer, arctic fox in winter - no explanation for how and why they adapt
What is a very complex example of the problem of design?
Bat - hunt their prey using echolocation which requires neurochemistry to receive and perceive the sounds, have to turn off their own hearing - people thought that the only way this occurs is if someone had designed bats
What is an example of the problem with design where the design doesn’t make sense?
Whale pelvis - serves no purpose to the whale (known as a vestigial structure)
What are Darwin’s 4 main theories?
- Variation
- Heredity
- Competition
- Natural Selection
What are homologies?
Similarities between organisms due to common ancestry
What is an example of an homology?
The human pelvis and the whale pelvis - at one point the human and whales had the same ancestry
That humans, bats and horses all have a humerus and ulna
What are analogies?
common traits found in different groups of species which are anatomically different, serve the same function, but evolved independently in the different groups of species.
What is the Modern Synthesis?
The Modern Synthesis refers to the fusion of Darwin’s theory of natural selection with Mendelian genetics, which occurred in the 1930s and 1940s. Before this, Darwin’s theory explained how species evolved, but lacked a mechanism for how traits were inherited.
What is a real world example to prove the theory of evolution?
darwin finches -
Drought led to changes in sizes of food - birds beaks size increased due to only large seeds/foods available - birds with smaller beaks died due to not being able to eat - less reproduction but more big beak sizes of offspring
What is the common misunderstanding of “Evolution is only in the past”?
Evolution is not only in the past, explanations help show why things occur in the present day.
i.e a common example is that nausea and vomiting at pregnancy have been selected for as they benefit the survival of the foetus - less chance of miscarriage
What is ‘essentialism’ and how does it conflict with evolutionary thinking?
The belief that each species has a fixed essence; evolution shows species change gradually and are connected by shared ancestry.
