B2

Question 1

Evolution

Answer 1

POPULATIONS of biotic organisms change over a series of generations

Does NOT refer to individual change instead cumulative change in heritable characteristics the population)

Question 2

Evidence For Evolution: Fossils

Answer 2

Show geological change is gradual and has been occurring for a long period of time (based on fossil deposits)

Relative Dating- Deeper sedimentary rock is older
Radiometric Dating- Determines age of rock/fossil

Patterns Found- Complexity of organisms have increased and living species are located in the same geographic region as most closely matched fossil

Question 3

Evidence for Evolution: Biogeography

Answer 3

Variation and geographic distribution of life in the past and present

Theory of Plate Tectonics- Earth used to be one supercontinent (Pangea) which separated into smaller continents by shifting plate tectonics

Question 4

Evidence for Evolution: Anatomy (Homologous, Analogous, Vestigial)

Answer 4

Anatomical comparisons suggest organisms with similar structure evolved from a common ancestor

Homologous Structure/ Features- Similar in structure but not in function
(Divergent evolution)

Analogous Structure/Features- Similar in function and appearance but not in origin (convergent evolution)

Vestigial Features- Features that are no longer useful now but may have been useful to an ancestor

Question 5

Convergent Evolution

Answer 5

When two unrelated species develop analogous traits (evolved genetically independently from each other so no common ancestor but are similar because they occupy similar niches)

Question 6

Evidence for Evolution: Biochemistry

Answer 6

Similarities in genetic code (DNA is hereditary)

Question 7

Artificial Selection

Answer 7

Humans selecting and breed individuals with desire traits (Dramatic change over short time)

Question 8

Buffon

Answer 8

Suggested species could change overtime

Question 9

Linnaeus

Answer 9

Suggested few species at creation became hybrids=New species

Question 10

Erasmus Darwin

Answer 10

All life came from a single source (common ancestor)

Question 11

Lamark

Answer 11

First theory of evolution with a mechanism

Suggested new species are created from spontaneous generation (evolved from dead matter) and become more complex

Lamarckism- Organisms want to change for the better and so they are more compatible with the environment so they produce new parts. These physical changes in an organism can be passed down to offspring (Acquired characteristics can be inherited)= FALSE but recognized environments role in evolution

Question 12

Darwin’s Theory of Natural Selection

Answer 12

All species display inherited variation. This variation makes some individuals better adapted to survive and reproduce= Survival advantage that becomes more common in the population= Evolved population

Natural Selection works to select traits that increase chance of survival in population (pepper-moth gizmo)

Question 13

5 Points of Darwin’s Theory

Answer 13

Overproduction- # of offspring is greater than the amount the environment can sustain

Competition- Species compete over limited resources (Inter and Intra)

Variation- Sexual reproduction= Variability in population
(Offspring inherit most of parents traits but some are random (genetic mutation)

Survival of the fittest- Environmental acts to select favourable traits which gives survival advantage and increases chance of survival; individuals best adapted to their environment are more likely to survive and reproduce (selection by natural=natural selection)

Speciation- Individuals do not change, populations do. Accumulation of new traits over a long time=New species

Question 14

Sexual Reproduction

Answer 14

Production of offspring via union of two different but compatible sex cells

Variation in phenotype because Meiosis causes reshuffling of genes so offsprings inherited random combos of alleles and chromosomes

Question 15

Mutations

Answer 15

Random changes in DNA

Question 16

Causes of Mutations

Answer 16

Environmental factors, errors when cells are making copies of DNA, meiosis (new combos of alleles are created due to crossover)

Question 17

Impacts of Mutations

Answer 17

Neutral Mutations- No immediate impact on individual fitness or reproductive success

Harmful Mutations- May cause genetic disorders

Beneficial Mutations- Can give selective advantage that can be passed on to offspring

Question 18

Asexual Reproduction

Answer 18

Reproduction without mate so offspring is identical to parent (only source of variation is mutations)

Question 19

Adaptations

Answer 19

Characteristic changes as a result of natural selection (inherited trait) that increase chance of survival

Structural- Physical characteristics
Behavioural- Done in response to external stimulus (migration, hibernation)
Physiological- Process inside organisms body

Question 20

Allopatric Speciation

Answer 20

Accumulation of genetic differences between populations while they are geographical isolated

Physically Barrier- Separates a single interbreed population into 2 or more groups (Mutations are not shared with other population)

Natural Selection works separately on the population so they evolve independently in response to different environments.

Then groups are no longer sexually compatible due to accumulated physical and behaviour differences so since they can’t reproduce together they are not the same species anymore

Example- Darwin’s Finches (Became different species of Finches due to geographical isolation

Question 21

Theories of Evolution: Gradualism

Answer 21

Species change at a slow, steady and gradual pace; Evolution occurs by gradual accumulation of small changes (not represented by fossils which show abrupt change)

Question 22

Theories of Evolution: Punctuated Equilibrium

Answer 22

Rapid bursts of speciation followed by long periods of stasis or equilibrium where little to no change occurs because after initial burst of change it is assumed that species is well adapted to environment

Question 23

Macroevolution

Answer 23

Evolution on a grand scale

Cambrian- Species rapidly evolved into many species
Palaeozoic- Eradicated 90% of known marine species
Permian Extinction- Unknown cause but suspected to be tectonic plates
Mesozoic- Asteroid assumed to cause extinction (Dinosaur era)

Question 24

Divergent Evolution

Answer 24

Evolution of species from a common ancestor (Homologous)

Darwin’s Finches