Lecture 2: Darwins Theory of Evolution

Question 1

Typological Thinkining

Answer 1

The idea that there is one “true” form of species.
Also it is assumed that the first species (such as a cat) was a perfect cat and that it is unchanging over time

Question 2

What causes scientists to believe that life was not created supernaturally (but rather organically)

Answer 2

Once it became apparent that the Earth was more than 6000 years old, scientists began to find alternatives to the supernatural origins of different species in the late 1700s.

Question 3

What were 5 thoughts of Lamarck?

Answer 3

1. Species change gradually through time
2. Each speices represents a stage in its evolution from a simple ancestor to a more complicated and perfect form
   3.Each new species arose through spontaneous generation from non living matter
   4.Characteristics acquired during an organism’s lifetime will be passed on to its offspring (inheritance of acquired characteristics)
3. No common ancestry. Each species had its own origins and its own evolutionary trajectory

Question 4

Why were LaMarck and Erasmus Darwin important figures?

Answer 4

They proposed natural forms of evolution (Change through time)

Question 5

What was Darwin’s first hypotheses, prior to evolution?

Answer 5

• Earthquakes can cause the uplifting of mountain ranges after experiencing an earthquake in Peru
• Role of corral in producing and maintaining islands

Question 6

Why did Darwin not publish the theory until 1858

Answer 6

Darwin had formulated the theory of evoluton in 1840, but grew ill.
He published on nautural selection in 1858 in response to an article given to him by Alfred Wallace.
Darwin rushed out his book “Origin of Species” in 1859.

Question 7

What are the five components of Darwin’s theory of evolution?

Answer 7

1. Steady Change: Species don’t stay the same forever
2. Gradulism: changes in species take place** gradually **
3. Common descent: Singular origin of life
4. Natural Selection: Evolutionary change by the preferential survival and reproduction of organisms that are better adapted
5. Multiplcation of species (speciation): New species can evolve from existing ones

Question 8

Natural selection (Darwin’s 4 observations)

Answer 8

1. There is variation among individuals: (in ways that increase survival and reproduction) IMPORTANT
2. Variation is heritable: If variation is heritable, the offspring of successful competitors will also tend to be successful competitors
3. Species produce more offspring than can survive: Competition for resources; All species can overproduce and there are limits to most animals and plants population growth
4. Differential reproductive success: Individuals that are more successful are more likely to survive and reproduce (have better fitness)

The only original component of Darwin’s theory of evoluton

Question 9

What is a theme that arises due to individuals with higher reproductive success

Answer 9

Over time, individuals that successfully reproduce will begin to outnumber less successful competitors and population will become better adapted

Question 10

Evolution by natural selection occurs when _________________

Answer 10

heritable variation leads to differential reproductive success

Question 11

Fitness (definition)

Answer 11

the ability of an individual to produce surviving fertile offspring, relative to other individuals in the population

Question 12

Adaptation (definition)

Answer 12

A heritable trait that increases the fitness of an individual relation to another individual that lacks the trait

Question 13

Biston betularia

What are the 2 forms, How do the 2 exemplify natural selection

Answer 13

Melanic form: darker, black
Peppered form: a lighter “natural” form
The more crypitcally colored moth would have higher rates of survival=higher reproductive success