Evolution Lecture 1

Question 1

Evolution

Answer 1

Change in biological entities over time (over generations). This could be in the make of populations or sequence in proteins. Results in a vast diversity of past and present organisms. It’s a unifying concept in biology. Important in of itself and to many other aspects of biology (and life sciences in general). It occurs as the unequal reproductive success of individuals intimately leads to adaptation to their environment (if it stays the same).

Question 2

What is therein thing to distinguish between living and non-living?

Answer 2

Their ability to participate in biological evolution.

Question 3

Evolution is the scientific explanation for what?

Answer 3

The unity (sharing traits) and diversity for organisms and the traits adapted to their environment.

Question 4

Diversity

Answer 4

Different traits, heritable changes occurred after the two species diverged from the common ancestor.

Question 5

COVID example of evolution?

Answer 5

How there is different variants and subvarients appearing at different times (some going extinct and new ones appearing). We see this because the variant that is better at getting transmitted will replace the old variant. The new variants also have greater reproductive successes thus becoming more frequent. This is microevolution by natural selection.

Question 6

Human body evolution example?

Answer 6

How the respiratory and digestive tract cross over. The lungs are in front of the stomach. The paths cross to get there. This causes air and food going in the wrong place, causes choking. This happened because it’s the end product of years and years of contingent evolutionary history. Ancestors couldn’t breathe through their nose.

Question 7

Macroevolution

Answer 7

The unfolding of evolutionary history over hundreds of millions of years.

Question 8

The Origin of Species

Answer 8

Published by Darwin in 1859, it’s one of the most important books in biology.

It explained in great detail that evolution existed and happened (leading to a certain pattern of the diversity of life). It covered how there is unity, diversity, and a match between organisms and their environments.

It shows an important connection between natural selection and the capacity for organisms to overproduce. After this was published evolution went from being a fringe theory to wildly accepted by biologists.

Question 9

Charles Darwin’s two main ideas?

Answer 9

Tree of life and natural selection.

Question 10

Was Darwin the first biologist?

Answer 10

No, he wasn’t even the first evolutionist.

Question 11

What was biology like before evolution?

Answer 11

People always knew and wondered about how species are so different from each other. They thought species were fixed were unchanging and perpetual. That species had always been on eater and were created by supernatural means. If this was true then the species today would have been here from millions of years ago.

Question 12

Scala naturae

Answer 12

Proposed by Aristotle. It’s a ladder of increasing complexity. It organizes species and thought there was a great continuous series and a fundamental linear order on which we can place all the species on earth. They saw that species were different before each other. A popular way of thinking about the diversity of lie.

Question 13

The 3 domains?

Answer 13

Archaea, Bacteria, and Eurkarya

Question 14

Order of taxon

Answer 14

Domain, kingdom, phylum, class, order, family, genus, and species

Question 15

Carolus Linnaeus

Answer 15

Father of Taxonomy. Promoted idea of Hierarchical, Nested Classification (and formal Ranks). His idea was that classification should be hierarchical nested classification and popularized the idea of giving formal ranks to different levels in that hierarchy. The idea has longevity. He still thought that species were fixed and didn’t believe inn evolution. He didn’t ascribe the resonances among species to be evolutionary kinship, but rather the pattern of their creations. He developed the scientific name.

Question 16

Taxonomy

Answer 16

Science of organizing and classifying species.

Question 17

Scientific name

Answer 17

Binomial nomenclature. The same in any language and provides a unique name for an organism such that two people can be sure that they are referring to the same organism. Genus then species.

Question 18

Linnaean Classification

Answer 18

It’s not a linear scale. But “boxes” with related species in it. The bigger the box the more species are in it. It’s a good system because of Darwins idea of the pattern of evolution. Still used today. Consists of a hierarchy of groupings, called taxa (singular, taxon).

Question 19

Paleontology

Answer 19

The study of fossils. It was popular around the time the Linnaeus was dying. A lot of the work was done in France. Rocks of different age in the same location
contain different species. Many species preserved as fossils are no longer seen on Earth: Extinction. They found different fossils in each layer. Top layer is younger species and old layers are older species.

Question 20

Fossils

Answer 20

A record of organisms that used to be alive. The layer of rocks had fossils in it.

Question 21

Strata

Answer 21

Superimpose layers of rock that represent the passage of time.

Question 22

What is earth’s biodiversity always on?

Answer 22

A downtrend

Question 23

What did Lamarack (1809) notice about the fossils?

Answer 23

Observed progressions of similar species in
the fossil record Proposed new species arise by modification of existing species (= evolution). The species change into each new one.

Question 24

What are Lamarck’s two ideas?

Answer 24

Pattern and Process/Mechanism of Evolution (both are incorrect).

Question 25

Pattern

Answer 25

Living world made up of many separate lineages with independent origins (life arises from non-life). Each lineage progresses (‘strives’) towards greater complexity/perfection. The species that were more complex had more time to evolve. Said to be many origins.

Question 26

Process/Mechanism

Answer 26

Use-and-disuse of parts, with inheritance of acquired characters. How the more you use the body part, you’ll end up with a more developed version of it (true), then it will get passed on to your kids (false). However, he didn’t come up with this, they were common ideas at the time. It shows that the individual is evolving which isn’t true, it’s the population.

Question 27

Example with giraffes and the process?

Answer 27

They have short neck then stretch them to reach the more food. Then the offspring will have longer necks. Slowly and slowly, after many generations, the giraffes will have long necks.

Question 28

Lamarck’s overall ideas and results?

Answer 28

Explains variation in ‘complexity’ among species.
Mechanism not well supported (in hindsight). Poor fit to biological classification (the taxons).

Question 29

Charles Darwin

Answer 29

After Lamarck. Med School drop-out. He was interested in the natural world, so he went to Cambridge and looked at rocks. Then he went on the Beagle expedition that charted the South American coastline. On there he collected plant and animals. He described how organisms are suited to their environment. Species that live closer together are more alike. Then he published the origin of species.

Question 30

What two parts of evolution did Darwin look at?

Answer 30

Pattern and Process.

Question 31

Darwin’s pattern

Answer 31

Living things united in one branching tree of relationships, called the tree of life. It’s an ever-branching tree. When you back in time all the species will connect (only one origin). New lineages constantly being created by existing lineages splitting in two. It shows how related they by when they branch off. They have a most recent common ancestor.

Question 32

Descent with modification?

Answer 32

Contemporary species arose from a succession of ancestors that differed from them. Organisms share descent but also experience independent evolution. It has two parts: unity and diversity.

Question 33

Unity

Answer 33

Species A and B are similar because of their shared history before their most recent common ancestor. They go through almost all of the same evolutionary changes.

Question 34

Diversity

Answer 34

But Species A & B also differ because of independent changes in their lineages after divergence from their most recent common ancestor.

Question 35

Does the tree of life and Linnaean Classification work together?

Answer 35

Yes

Question 36

Darwin’s Process

Answer 36

Evolution occurs primarily because of the action of Natural Selection. Key point: Individuals of a species
belong to populations

Question 37

Natural Selection

Answer 37

Causes evolutionary charges in population.

Question 38

Populations

Answer 38

Groups of organisms. Collection of individuals and their descendants over generations.

Question 39

Ingredients of Natural Selection?

Answer 39

Heritable Variation. Excess Production.
Differential Success

Question 40

Heritable Variation

Answer 40

Individuals in a population are born differing in many traits (many features), causing them to be different as they grow up. Many traits can be passed on from
parents to offspring (i.e. are heritable). Eg. shell color in snails.

Question 41

Excess Production

Answer 41

In any population, more offspring are produced than ‘needed’ to maintain it. The consequence of this is when resources are limited, many of the offspring fail to survive (or, at least, do not reproduce). This is very common. Creates competition within the species. It is the idea of struggle for existence which isn’t fair.

Question 42

Differential Success (& Fitness)

Answer 42

How many offspring can they expect to have. Because of their differing traits, some individuals are more likely than others to survive & reproduce = will produce more viable offspring on average. This is the concept of fitness.

Question 43

What’s having a high fitness?

Answer 43

Expected to produce more viable offspring on average, than members of the same population.

Question 44

How are heritable traits passed on?

Answer 44

Heritable traits that helped individuals to have more viable offspring on average will tend to be passed on to those more numerous offspring. With time, these traits will tend to become more frequent in the population (& unfavourable traits become less frequent). This is evolution (the population has evolved). The average state of the trait in the population will have changed over time. If there is no different genes in the population there is no more heritable variation.

Question 45

Can natural selection create a variation?

Answer 45

No, it acts on existing variation. It can’t explain to way the variation happens.

Question 46

How do variations arise?

Answer 46

From mutations (changes) in the genome. Darwin didn’t know this but he observed natural selection.

Question 47

Adaptations

Answer 47

Inherited characteristics that enhance their survival and reproduction in specific environments. It’s natural selection over time. Organisms are well suited to their environment.

Question 48

What does artificial selection show?

Answer 48

Artificial selection on heritable variation that is present or arises in existing species shows plausibility of evolution by natural selection on the same variation.

Question 49

Darwins artificial selection with pigeons?

Answer 49

He breed pigeons. They all looked different (from artificial selection) but were the same species. The original populations have lot of heritable variation in them (has to be for artificial selection to work).

Question 50

Fox example?

Answer 50

Fox species with different adaptations to different
environments - e.g. colouring, coat thickness, ear size. White and red fox.

Question 51

Example with the giraffe and bacteria?

Answer 51

The giraffe is well adapted to have to look for food and it takes a long time to reproduce. Bacteria are well adapted for rapid reproduction because they are very simple. It doesn’t mean they are bad at evolution but instead are really well adapted to a completely different environment.

Question 52

Does Darwin say organisms evolve to become more complex?

Answer 52

No, there is no intrinsic evolutionary progression.