Section 2 Evolution: Natural Selection, Speciation, Evolution History And Phylogeny

Question 1

what does the evolution theory explain

Answer 1

Explains the adaptations of organism and the unity and diversity of life

Question 2

What did Charles Darwin hypothesized and what theory did he compose?

Answer 2

Through comparison and observation, hypothesized
“Descent with modification”

Composed theory of evolution by natural selection
- hypothesis supported by many researches over 150 years -> concept of evolution by natural selection was regarded as a theory afterwards

Question 3

Descent with modification

Answer 3

Parents genes passing down to offspring - “modification” then turned into Theory of evolution by natural selection
- observe that organisms have different traits

Question 4

What are Darwin’s observations

Answer 4

Variability in character traits

Heritability of character traits

Overproduction of offspring

Competition between offspring

Question 5

Variability in character traits

Answer 5

(Charles Darwin’s observation)
Stating that character traits vary

Question 6

Heritability of character traits

Answer 6

(Charles Darwin observation)
Reproduce and offspring will inherit parents traits
- 2 different variation combinations
Gametes 1/2 from each parent

Question 7

Overproduction of offspring increases?

Answer 7

(Charles Darwin’s observation)
Increasing the amount of offspring produces will
increase chances of a new trait to emerge
Increasing the beneficial trait

Question 8

Competition between offspring

Answer 8

(Charles Darwin observation)
Beneficial trait increases survival and mating rate
- passing down favourable genes

Question 9

What are the Evidences for evolution

Answer 9

Homologous structures
Molecular evidence (microevolution)

Question 10

What are Homologous structures and what are the two types?

Answer 10

Between different species that have similar characteristics but have different functions
Ex) bone structures are similar

There are two types of homologous structures
1) development homologies (embryonic structures(
2) Vestigial homologies (structural remnants) that still remains however doesn’t affect the function

Question 11

Homology

Answer 11

Similarity resulting from common ancestry

Question 12

Molecular evidence

Answer 12

Microevolution: see changes in the structure

1. DNA sequences
   Ex) red panda align DNA sequences together to find similarities
   - similarities closely related to each other
2. RNA sequences
3. Protein sequences

Question 13

Natural selection

Answer 13

Happened naturally by environmental pressure
Happens over long periods of time

Natural selections happens from
1. Favourable variations
2. Unequal inheritance

Question 14

Favourable variations

Answer 14

(Natural selection)
Survive longer -> more offspring
- passed on will be higher

Question 15

Unequal inheritance

Answer 15

(Natural selection)
“Survival of the fittest”
- accumulation of favourable traits

UNFAVOURABLE traits disappear

Resulting, in gradual change in population overtime

Question 16

Ancestral canine gives rise to the African wild dog, coyote, fox, wolf and jackal throughout 100,00s-1,000,000s of years whats this an example of?

Answer 16

Example of natural selection
Happens naturally by environmental pressures and over long periods of time

Question 17

Artificial selection

Answer 17

Creates a new type of species to their desire
Pick and choose and create a pressure on species
Takes a shorter period of time compared to natural selection

Question 18

There is a pesticide application on insects and there are some survivors and some die. Additional applications of the same pesticide will be less effective because…

Answer 18

(Example of molecular evidence)

The survivors will carry the resistant gene to pesticide spray and next offspring will carry this resistant gene therefore the same pesticide wont work
- same pesticide will be less effective and frequency of resistant insects in population will grow

Question 19

Types of artificial selection

Answer 19

Domestication

Selective breeding

Horticulturalists

Animal breeders

Question 20

Kale, rhubarb, broccoli and cabbage are examples of

Answer 20

Horticulturalists

Question 21

German shepeard, Yorkshire terrier, English springer spaniel, mini-dachshund, and golden retriever are examples of what selection

Answer 21

Artificial selection and a type of Animal breeders

Question 22

Canola oil plant (cooking oil) example of

Answer 22

Horticulturalists
Produce an oil thats not too healthy - artificially produced (arise from genetically modified plants)

Question 23

How can natural selection affect the distribution of phenotypes in a population

Answer 23

Stabilizing population
Directional selection
Disruptive selection
(Look at graphs in notes slide 12-14)
Sexual selection

Question 24

Stabilizing selection

Answer 24

(How natural selection can affect the distribution of phenotypes in a pop.)
Favours intermediate phenotypes
- narrow in the middle)

Question 25

Directional selection

Answer 25

(How natural selection can affect the distribution of phenotypes in a pop.) Shifts the overall makeup of the population by acting against individuals at one of the phenotypic extremes - theres a selective pressure put on a population shifting the population

Question 26

Disruptive selection

Answer 26

(How natural selection can affect the distribution of phenotypes in a pop.) Typically occurs when a environmental conditions vary in a way that favours individuals at both ends of a phenotypic range over individuals with intermediate phenotypes - middle taken out; valley = disruptive

Question 27

Sexual selection

Answer 27

(How natural selection can affect the distribution of phenotypes in a pop.) A form of natural selection in which individuals with certain characteristics (that attract others a lot more) are more likely than other individuals to obtain mates

Question 28

Why is natural selection the mechanism of evolution?

Answer 28

due to deritable variation, normal distributions and it can lead to adaptive evolution Heritable variation - pesticide example) those with the best resistant gene will survive Normal distribution (bell shaped curve) Because of natural selection will lead to adaptive evolution - if we live in an adaptive evolution, next generation will have to be adaptive whenever the natural selection is applied too Genotypes -can lead to-> favourable phenotypes -genetic makeup code for physical traits Genotypes -can lead to-> unfavourable phenotypes Doesnt mean that the gene is good or bad, just have a higher chance of adaptation and survival in that point in time

Question 29

Heritable variation example

Answer 29

Why natural selection is the mechanism of evolution pesticide example) those with the best resistant gene will survive

Question 30

Normal distribution

Answer 30

why natural selection is the mechanism of evolution bell shaped curve

Question 31

Why should we live in an adaptive evolution?

Answer 31

Because of natural selection will lead to adaptive evolution - if we live in an adaptive evolution, next generation will have to be adaptive whenever the natural selection is applied too Genotypes -can lead to-> favourable phenotypes -genetic makeup code for physical traits Genotypes -can lead to-> unfavourable phenotypes Doesnt mean that the gene is good or bad, just have a higher chance of adaptation and survival in that point in time

Question 32

Why did Gregor mendel use pea plants in his experiment for the model of inheritance?

Answer 32

easy to grow the flowers are bisexual short generation time excellent disease resistant and optimal survival rate the traits (or characteristics) are distinguishable (tall vs short, wrinkle vs round, flower color, or pod color or shape)

Question 33

Mendel proposed a model of inheritance based on..? explain the process of the dominant traits and alleles

Answer 33

Characteristics such as flower, color, plant height and seed shape the dominant trait could mask the present of the recessive trait the pair of alleles are separated and during gamete production such that each gamete (sperm or egg) randomly recieved one allele - different alleles control different traits and were inherited independantly from one another

Question 34

what is a genotype and phenotype

Answer 34

genotype = codes for phenotype phenotype = the traits that are being expressed (genes being expressed physically)

Question 35

the hardy weinberg equation

Answer 35

p^2 + 2pq + q^2 = 1 p^2 = dominant homozygotes 2pq = dominant heterozygotes q^2 = recessive homozygotes

Question 36

What is q and p in the hardy-weinberg equation

Answer 36

q = frequency of recessive allele p = frequency of dominant allele for both can be any letter

Question 37

The hardy weinberg equillibrium states that... and can be used to test..

Answer 37

States that allele and genotype frequenicies will remain constant if 1) population is large 2) mating is random (what genotype or phenotype will be expressed) 3) there is no mutation, gene flow, or natural seletion

Question 38

The hardy weinberg equillibrium can be used to test?

Answer 38

Can be used to test whether evolution is occuring in a population by comparing allele frequencys between the parent and offspring generations

Question 39

Three main causes of microevolution

Answer 39

(microevolution = molecular evidences Natural selection Gene flow genetic drift (the bottle neck and founder effects)

Question 40

Natural selection

Answer 40

is a mechanism of microevolution (molecular evidence) is the the process whereby organisms better adapted to their enviornment tend to survive better and produce more offspring

Question 41

gene flow

Answer 41

allele frequencies in a population are changed when fertile individual in the population move into or out of a population or in between population - this tends to reduce the differences between populations

Question 42

Genetic drift

Answer 42

one of the main causes of microevolution Natural events causes allele frequencies to fluctate unpredictably from one generation to another. - the smaller the pop. the more impact genetic drivt is likely to have (an allele can be lost completely from a small pop) Two situations can happen involve the bottle neck affect and the founder affect

Question 43

The bottle neck affect

Answer 43

In the original population, different alleles (traits) present at different frequencies The bottle neck affect = natural enviornment changes = population reduced The surviving population will contain even less (or maybe completely lost) of the less frequent allele

Question 44

What two situations can happen during genetic drift

Answer 44

The bottle neck affect and the founder affect

Question 45

Explain The founder effect and provide an example

Answer 45

A part of genetic drift (a mechanism for microevolution) new gene is being introduced into a new population through a small group of founder (or colonist) - so the frequncy of gene becomes the dominant one in the population example) the colonists came and populated a small island and introduced new genes into the population gene pool - the gene from the colonist become the founder gene to the population on the island and eventually become the dominant gene there The founder gene in the founder effect can be positive or negative toward the new population

Question 46

Different between the bottle neck affect and the founder affect

Answer 46

**Bottle neck affect:** Different alleles present at diff times at different frequences and the bottle neck is the natural disaster **The founder affect: ** New gene is being introduced into a new population through a small group of founders (colonist) = freq. gene becomes the dominant one in the pop. These are a part of genetic drift which is a mechanism for microevolution

Question 47

Speciation

Answer 47

The process of new species arise

Question 48

What are the two types of speciation

Answer 48

Allopatric speciation and Sympatric speciation

Question 49

Differentiate between the two types of speciation

Answer 49

Allopatric speciation: a group of population evolve into seperate species due to a period of geographical separation Sympatric speciation: a group of population evolve into seperate species without any geographical separation

Question 50

What are the different types of barriers

Answer 50

Prezygotic, Postzygotic and no barriers

Question 51

Prezygotic barriers

Answer 51

Includes habitat isolation, temporal isolation, behavioural isolation, mechanical isolation, and gamete isolation

Question 52

Habitat Isolation

Answer 52

(prezygotic barrier) species living in diff habitats

Question 53

Temporal isloation

Answer 53

(prezygotic barrier) species produce at different times

Question 54

behavioural isolation

Answer 54

(prezygotic barrier) species have different courtship behaviours or mate preferences

Question 55

Mechanical isolation

Answer 55

(prezygotic barrier) species have reproductive structures that dont fit together

Question 56

Gamete isolation

Answer 56

(prezygotic barrier) species with egg and sperm cells that can combine in fertilization - the number of chromosomes need to match b/w species and different species will have different numbers of chromosomes

Question 57

Postzygotic barriers

Answer 57

After egg is fertilized and they prdouce one generation offspring involves: reduced hybrid viability reduced hybrid fertility Hybrid breakdown (offspring may not be similar to grandparent)

Question 58

What is the difference between prezygotic barriers and postzygotic barriers

Question 59

What is the divergence of population

Answer 59

"smaller branches; tree" two or more population of ancestral species accumulate independant genetic changes (mutations) through time, which leads to reproductive isolation and different species arises - due to enviornmental pressure causing changes to favourable/unfavourable traits - allelic frequencies change due to non-random mating, natural selection, and/or new mutations arise

Question 60

What is convergent evolution? What are the two structures?

Answer 60

"multiple branches converges into one branch" Similar enviornments and natural selection produce similar adaptations in organism from different evolutionary lineages Analogous structures and homologous strucutres Analogous strucutres: similar functions, different structure Homologous strucutres: similar structure, different functions

Question 61

Difference between divergence of population and convergent evolution

Answer 61

Divergence population = two or more pop of ancestral species accumulate independent genetic changes (mutations through time, lead to reproductive isolation so diff species arise - smaller branches; a tree Convgerent evolution = similar enviornments and natural selection produce similar adaptations in organism from different evolutionary linages - Multiple branches converges into one branch

Question 62

What are the two structures in convergent evolution

Answer 62

Analogous structures and homologous strucutres Analogous strucutres: similar functions, different structure Homologous strucutres: similar structure, different functions

Question 63

Explain the earths formation

Answer 63

4.6 biollio years ago 5.Young earth began as molten mass then sorted into different layers of diff density, solidifying into diff crust layer

Question 64

What was the first cell that dated back 3.5 billion years ago

Answer 64

The first prokaryote (stromatolites fossil) - photosynthetic prokaryotes provide oxygen to the earths atmosphere

Question 65

What are the 4 primitive gases

Answer 65

hydrogen gas, water vapor, methane and ammonia

Question 66

Miller experiment explains

Answer 66

Millers experiment replicated the conditions of the earth and at this time he was using the 4 primitive gases, so he oxidized the 4 gases and the ozygen was the strong oxidiyzing agent. That organic molecules (hydrocarbon chain and amino acids) first evidence that molecules of life could have arisn spontaneously from inorganic precursours

Question 67

What is type of cells and organisms are involved in the evolution history? What is this result in?

Answer 67

Prokaryotes - utilizing CO2 First Eukaryotic cells then emerged (single cells) - multicellular eukaryotes Animals resulted into the colonization of the land

Question 68

How many mass extinctions are there

Answer 68

4.6 but rounded to 5 mass extinctions

Question 69

What is the order of evolution history

Answer 69

Hadean eon, Archaean eon, Proterozoic eon and Panerozoic eon

Question 70

What is the classification order

Answer 70

Domain (3 domains Bacteria, eukarya and archaea) Kingdom (3 kingdowms) Phylum Class Order Family Genus Species

Question 71

What is phylogeny

Answer 71

Evolution history of a species of group of species

Question 72

Phylogenetic tree

Answer 72

hypothesis of evolutionary relationships

Question 73

What is taxonomy (Look at diagram example in notes)

Answer 73

branch of biology concerned with identifying, naming and classifying species - homologous structures can be used to determine the branching sequence of an evolutionary tree - These homologies can include anatomical structure and/or molecular structure

Question 74

What is the evolution of population

Answer 74

Organisms typicall show individual varations - Mutations are the ultimate source of the genetic variation that serves as raw material for evolution

Question 75

Mutations

Answer 75

The ultimate source of the genetic variation that serves as raw material for evolution

Question 76

Fresh assorments of existing alleles arise every generation from what three random components of sexual reproduction

Answer 76

Crossing over, independant orientation of homologous chromosomes at metaphase I of meiosis and random fertilization

Question 77

What are the 5 key points about evolutionary adaptation in natural selection

Answer 77

1) natural selection is more of an editing prcoess than a creative mechanism 2) natural selection is contingent on time and place, favoring those hetiable traits in a varying population that fit the current, local enviornment 3) Although natural selection occurs through interactions between individual organisms and the enviornment, individuals do not evolve. Rather it is the population, the group of organisms that evolves over time 4) Natural selection can amplify or diminish only heritable traits 5) evolution is not goal directed; it does not lead to perfectly adapted organisms