Lektion 1

Question 1

What is common to all living organisms?

Answer 1

Ordered Complexity, growth, reproduction, energy use, Non-equilibrium steady state, Homostasis (mechanisms to maintain internal stability), sensing and evolutionary adaption.

Question 2

What are the main reasons an animal is the way it is?

Answer 2

Heredity, constance of DNA sequence, physical constraints (ex size and temperature), intergration of parts, adaptations to present enviroment, filing of a niche and adaptations to past enviroments.

Question 3

How does the mass in an mammal relate to the metabolic rate?

Answer 3

The metabolic rate decreases as the body mass increases.

Question 4

What does phyla mean?

Answer 4

A taxonomic rank above class and below kingdom. A group of organisms with a certain degree of evolutionary relatedness.

Question 5

Tree of life: what does topology indicate?

Answer 5

It indicates the relationship

Question 6

Tree of life: What does the nodes indicate?

Answer 6

They indicate the ancestors.

Question 7

Tree of life: what does the branch lenght indicate?

Answer 7

It indicates the amount of change/divergence.

Question 8

What phyla has the highest number of species?

Answer 8

Arthropods

Question 9

What is a basal group?

Answer 9

The direction of the base of a rooted phylogenetic tree or diagram. (basal is a very relative term)

Question 10

What is a crown group?

Answer 10

A collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection and all descendants of the most recent common ancestor.

Question 11

When was the Cambrian explosion?

Answer 11

500 million years ago

Question 12

When was the 6:th mass extinction?

Answer 12

65 million years ago

Question 13

When was the separation of humans and chimps?

Answer 13

10 million years ago

Question 14

what does a cladogram show?

Answer 14

It showns a classification based on presence/absence of features

Question 15

what is a phylogenetic tree?

Answer 15

It depicts the relationship between organisms and are based on evolutionary events. (topology, ancestors, amount of divergence etc)

Question 16

What are the main traits previously used for broad animal classification? (not used anymore)

Answer 16

Symmetry (radial vs bilateral), Cephalisation (sense organs ans brain at the fromt), type of gut (blind vs trough-gut), type of cavities (coelome), segmentation and presence of organs.

Question 17

How are animals classified today?

Answer 17

By molecular phylogenies (based on protein sequences)

Question 18

What are the two main principles of evolution?

Answer 18

1) Change
- change in DNa sequence
- Modification of developmental programs
- Allometric/quantitative changes
- Gain loss of charachters
2) speciation
Bifurcation in the tree of life

Question 19

What was Charles darwins revolutionary idea?

Answer 19

Evolutionary change by random variation and natural selection

Question 20

What is a species?

Answer 20

groups of actually or potentially interbreeding natural populations which are reproductively insolated from other such groups

Question 21

what are the mechanisms of speciation?

Answer 21

Genetic changes:
- Genetic drift
-Selection

Separation:
- Reproductive isolation
-Geographic isolation
- Invasion of separate niches

Question 22

What is stabilizing selection?

Answer 22

The population mean stabilizes on a particular non-extreme trait value. EX:
Birds that lays a lot of eggs may result in malnurished chicks
Birds that lay smaller cluthes of eggs may result in no viable offspring.
so a number of eggs that is the mean would be better

Question 23

What is directional selection?

Answer 23

When one extreme phenotype is favored over both the other extreme phenotype but also the moderate phenotype.
Ex: the moths that went from white and black to just black because of the pollution in england

Question 24

What is diversifying selection?

Answer 24

When extreme values for a trait are favored over the intermediate values
Ex
original population consist of white bunnies but gray and gray/white bunnies are favored because they blend better in with the enviroment

Question 25

What is parapatric speciation?

Answer 25

When two subpopulations of a species evolve reproductive isolation from one another while continuing to exchange genes

Question 26

What is perpatric speciation?

Answer 26

A population is introduced to a new niche that causes a small part of the pouplation to evolve reproductive isolation from the original population

Question 27

What is allopatric speciation?

Answer 27

when a barrier formation between a population causes two populations with reproductive isolation.

Question 28

what is sympatric speciation?

Answer 28

The evolution of a new species from an ancestral species while both continuing inhabit the same geographical region.

Question 29

What is divergent evolution?

Answer 29

Trait was found in ancestor but diverged in one or both lineages. One orgin, same start but different outcomes.

Question 30

What is convergent evolution?

Answer 30

Trait was not found in common ancestor but appeared twice independently. Several orgins and same solution.
Ex: the flying ability (found in birds, pterosaurs and bats)

Question 31

What is the evolution of eyes?

Answer 31

The eye evolved from a “simple” eye composed of pigmented cells and sensory neurons that respond to light and dark changes.

Common ancestry: All eyed bilaterian animals share the presence of a photoreceptor field and developmental mechanisms.

Convergent evolution: At the level of morphology ex camera eye

Divergent evolution: Many morphologies from a simple photoreceptor fiels bilaterian ancestor

Question 32

At what level does evolution happen?

Answer 32

At gene level

Question 33

How does new genes appear?

Answer 33

When duplications happen.
duplicated genes can be:
-lost
-Subfunctionalize
-Neofunctionalize (get new function)

Question 34

What are orthologs?

Answer 34

When a species diverges into two seperate species the copies of a single gene in the two resulting species are said to be orthologous.

Duplication by speciation

Question 35

What are paralogs?

Answer 35

Duplication within the same species