Chapter 1 - Evalution

Question 1

What is evolution

Answer 1

The process in which significant changes in the inheritable traits of a species occur over time

Question 2

What is a gene pool

Answer 2

Total of all alleles in a population

Question 3

What is genetic drift

Answer 3

Changes in allele frequency as a result of chance; such changes are more pronounced in small populations

Question 4

What is Bottle neck affect

Answer 4

A dramatic, often temporary reduction in population size usually resulting in significant genetic drift

Question 5

What is Founder effect

Answer 5

Genetic drift that occurs when a small number of individuals separate from their original population and find a new population

Question 6

What is the Gene Flow

Answer 6

The movement of alleles from one population to another through the movement of individuals gametes

Question 7

What is Stabilizing Selection

Answer 7

Selection against the traits of extreme variation which deviates from the population average

Question 8

What is Directional Selection

Answer 8

Occurs when environment favour individuals with more extreme variation of trait

Question 9

What is Disruptive Selection

Answer 9

When the environment favours the traits of 2 extremes rather than those of the population average

Question 10

What is sexual selection

Answer 10

Favours the selection of any trait that influences the mating success of the individual

Question 11

What is Sexual Dimorphism

Answer 11

Striking difference in the appearance of males and females

Question 12

What is Industrial Melanism

Answer 12

An effect urban population increasing the number of darker species

Question 13

What is Punctuated Equilibrium

Answer 13

A theory that attributes large evolutionary changes to relatively rapid sprouts of change followed by long periods of little or no change

Question 14

What is speciation

Answer 14

The evolutionary formation f new species

Question 15

What is reproductive isolating mechanism

Answer 15

Ant behavioural, structural or biochemical traits that prevent individuals of different species from reproducing successfully together

Question 16

What is pre-zygotic isolating mechanism

Answer 16

Reproductive isolating mechanisms that prevent inter species form MATING and FERTILIZING

Question 17

What are the pre-zygote can isolating mechanisms that prevent interspecies from mating + list examples

Answer 17

1) Ecological isolation- species that occupy separate habitat/niches in the same habitat but don’t encounter each other

Ex: ground squirrel species occupy different habitats

2) Temporal Isolation- reproductive cycle/mating occur at different times

Ex: similar plant species blooming at different time of day

3) Behavioural Isolation- mating rituals by one species prevent members of another species from recognizing/selecting a mate

Ex: different mating rituals or dances

Question 18

What are Pre-zygotic isolating mechanisms that prevent species from fertilizing + list examples

Answer 18

1) Mechanical isolation- structural differences in reproductive organs

Ex: floral features of plant can affect transfer of pollen

2) Gametic Isolation- prevent fertilization on molecular level

Ex: giant clams release eggs and sperm in water which recognize each other by molecular markings

Question 19

What’s post- zygotic isolating mechanism, and what are the 3 mechanisms

Answer 19

Post-zygotic isolating mechanism is a reproductive isolating mechanism they prevents the maturation and reproduction in offsprings from interspecies reproduction

1) Zygote mortality-no fertilized zygote or embryo develop to maturity
2) Hybrid inviability - hybrid offspring is unlikely to live long
3) hybrid infertility - offspring of interspecies is strong but sterile like a mile

Question 20

What is Gradualism

Answer 20

A theory that attributes large evolutionary changes in a species to the accumulation of many small ongoing changes and processes

Question 21

What is convergent evolution

Answer 21

Occurs when two or more species become increasingly similar in phenotype due similar selective pressures

Question 22

What is divergent evolution

Answer 22

Occurs when two or more species become increasingly different traits due different selective pressures or genetic drift

Question 23

What is Adaptive radiation

Answer 23

Process in which divergent evolution occurs in rapid succession or simultaneously among a number of groups to produce three or more species or higher taxa

Question 24

What contribution did Cuvier make

Answer 24

Catastrophism- theory that numerous global catastrophes in the past had repeatedly causes he extinction of species that were the replaces by newly created forms

Question 25

What contribution did Hutton make

Answer 25

Actualism- theory that the same geological process occurring in the present occurred in the past Ex: erosion

Question 26

What contribution did Lyell make

Answer 26

Uniformitarianism- theory that the earths surface has always changed and continues to change through similar, uniform and gradual changes

Question 27

What contribution did Buffon make

Answer 27

Proper that species could change over time, and That these changes could lead to new organisms

Question 28

What contribution did Erasmus Darwin make

Answer 28

He believed that humans were closely related to primates and that all organisms developed from one species

Question 29

What contribution did Lammrack make

Answer 29

For species to change overtime, they must adapt to environmental changes. Believed that species gradually become more complex, didn't believe new species could emerge

Question 30

What contribution did Eldrege and Gould make

Answer 30

Theory of punctuated equilibrium - species evolve rapidly over evolutionary time - speciation usually occur in small populations and intermediate fossils are rare - after initial bursts of evolution, species don't emerge don't change significantly over long periods of time

Question 31

What is Darwins Theory of Evolution by Natural Selection

Answer 31

- Members of the same species compete with eachother for survival - Individuals with more favourable variations are more likely to survive and pass them on, survival isn't random - As more offsprings with these traits survive, the favourable variations become more common

Question 32

What is the hardy Weinberg principle

Answer 32

Genotype and allele frequencies remain constant from generation to generation in the absence of other evolutionary influences The conditions are: - The population is large - mating opportunity is equal - no mutations - no migration - no natural selection, equal reproductive success - no genetic drift

Question 33

What are factors that can cause evolution

Answer 33

- When a population is small chance fluctuations can cause changes in allele frequency - When mating opportunities are non random, individuals that are preferred as mates will pass on their alleles in greater numbers than the less preferred mates - when genetic mutations occur new alleles/change in alleles can alter the frequency of the new/original alleles - migration removes alleles from on pop to another

Question 34

What is some evidence of evolution

Answer 34

- many species bearing strikingly similarities to other species both extinct and living, in the same region ere related to one another - inferences about evolutionary ancestors could be observed through homologous, analogous and vestigial features - favourable traits are inherited due to competition and number of offsprings that survive and pass on the traits - embryological homologous features can conclude to a related ancestor, such as a tail and gills in both human and chicken embryos

Question 35

What are vestigial features

Answer 35

Rudimentary and non functional features that are homologous to fully functioning structures in closely related species Ex: digits in pigs, horses and dogs

Question 36

What was Darwins role on the HMS beagle

Answer 36

To observe, record and collect specimen

Question 37

Explain Darwin's finches on Galápagos Islands

Answer 37

Different beak types in the finches resembles their diet and habitats, for example cactus finch have long pointed beaks, Ground finches have deep and wide beaks to eat hard seeds. They all had common ancestor from mainland, the finches then migrated to the islands and had variety of different ways to change their diet, over time those favourable traits were passed and became the modern finches through natural selection

Question 38

What is natural selection

Answer 38

When environment depicts what favourable traits should be passed onto organisms and future generations