5 evolution (bioninja summary)

Question 1

evolution definition

Question 2

what is evolution in terms of genes

Answer 2

a change in the allele frequency of a populations gene pool over successive generations

Question 3

what are the 2 proposed theories of evolution?

Answer 3

lamarck – species change via habitual use and disuse (rejected bc no genetic basis)

darwin (and wallace) – species change via natural selection (reinforced by modern genetics)

Question 4

3 ways genetic variation is maintained in a population

Answer 4

• mutations (gene sequence changes)
• sexual reproduction (new gene combinations)
• gene flow (immigration and emigration)

Question 5

2 ways population variety is altered

Answer 5

• random chance (genetic drift) - variant just so happens to die in chance event
• directed intervention (natural/artificial selection)

Question 6

what is speciation?

Answer 6

when populations are isolated and the level of genetic divergence gradually increases (the longer the populations are seperated)

Question 7

what supports speciation?

Answer 7

continuous variation over geographical range of related pops – gradual divergence

Question 8

when does speciation occur?

Answer 8

when populations diverge to the extent that they can no longer interbreed and produce fertile, viable offspring

Question 9

what is a fossil?

Answer 9

the preserved remains or trace of a past organism

Question 10

what is the fossil record

Answer 10

the totality of all fossils

Question 11

what does the fossil record show? (law of fossil sucession)

Answer 11

shows that changes have occurred in organisms
– these changes have occurred in a consistent
sequence of development

Question 12

example of law of fossil succession

Answer 12

ferns always appear before flowering plants

Question 13

transitional fossils definition

Answer 13

represent intermediary forms within the evolution of a genus and demonstrate species connections

Question 14

example of transitional fossils

Answer 14

The archaeopteryx links the evolution of birds (wings and feathers) to dinosaurs (jaws and claws)

Question 15

what is selective breeding? how is it effective?

Answer 15

mating of animals with desired characteristics (artificial selection)

changes happen over fewer generations – phenotype extremes are promoted

Question 16

example of selective breeding

Answer 16

Large variation in types of dog breeds

Question 17

what is the “molecular clock”

Answer 17

If a particular gene has a stable mutation rate, the time of evolutionary divergence can be estimated

Question 18

what are vestigial sturctures

Answer 18

Some species show the presence of FUNCTIONLESS or reduced REMNANTS of organs that were once present in ancestors

Question 19

example of vestigial structures

Answer 19

whales have a pelvic bone (ancestors were terrestrial)

Question 20

what are homologous structures

Answer 20

anatomical features that share common basic structure but have different functions

Question 21

what causes anatomical features to differ

Answer 21

adaptive radiation (organisms adapt to different niches)

Closely related species demonstrate greater homology

Question 22

example of homologous structure

Answer 22

pentadactyl limb (diff appendages, same bone strcuture)

Question 23

what can be gleaned from comparing embryonic development + examples

Answer 23

suggests a common evolutionary pathway

• All terrestrial animals have non-functioning gill slits
• Many vertebrate have a primitive tail in early stages

Question 24

what is biogeography

Answer 24

Biogeography is the distribution of species across an area

• Related species will usually be found in close proximity
• E.g. Monotremes are exclusive to Australia/New Guinea

Question 25

how can exceptions to biogeography be explained?

Answer 25

continental drift

Question 26

conditions for natural selection

Answer 26

- genetic variation present - competition for survival - environmental selection pressures - beneficial traits survive and repro = more common

Question 27

key components to natural selection (ICEAGE)

Answer 27

* Inherited variation * Competition * Environmental selection * Adaptations * Genotype frequency changes * Evolution occurs

Question 28

examples of selection pressures (PANDAS)

Answer 28

* Predator / prey dynamics * Abiotic factors (e.g. climate) * Nutrient supply (food source) * Diseases / pathogens * Available resources (e.g. light) * Space requirements (habitat)

Question 29

what are adaptations

Answer 29

traits that make an individual suited to its environment and way of life can be structural, behavioural, physiological, biochemical or developmental

Question 30

how do populations evolve according to environmental conditions

Answer 30

different adaptations based on the functional position of the org in the enviro in its ecological niche

Question 31

example of adaptation

Answer 31

change in beaks of finches on Daphne Major

Question 32

how does binomial nomenclature work

Answer 32

proposed by carl linneaus in 1735 two parts 1. genus written first, capitalised 2. species in lower case

Question 33

what is taxonomy

Answer 33

classifying organisms based on shared characteristics (or taxa) more shared taxa = more closely related

Question 34

taxa order

Answer 34

Kingdom = katy phylum = perry class = comes order = over family = for genus = grape species = soda

Question 35

3 main domains of life/classification

Answer 35

- eukarya (all eukaryotic) - archaea (prokaryotic extremophiles) - eubacteria (pathogenic bacteria)

Question 36

eukarya vs archaea vs eubacteria 4

Answer 36

histones: present, present, absent introns: present, present absent nucleus: present, absent, absent ribosome: 80s, 70s, 70s

Question 37

what is natural classfication

Answer 37

involves grouping organisms according to common ancestry (rather than by common characteristics) * allows for species to be identified by their evolutionary pathways and enables the prediction of traits within a group

Question 38

disadvantage of natural classification

Answer 38

taxonomists may need to reclassify groups if new phylogenetic evidence emerges

Question 39

what is a dichotomous key

Answer 39

involves sequentially dividing organisms into two categories until every organism is individually identified

Question 40

what is cladistics

Answer 40

classifying organisms into groups of species (clades) * A clade consists of a single common ancestor and all descendants

Question 41

what are cladograms

Answer 41

tree diagrams where each branch point represent the splitting of two new species groups from a common ancestral species * Each branch point (node) represents a speciation event * The more nodes between groups, the less related the groups are

Question 42

homologous vs analogous features

Answer 42

diff structures // similar structures diff selection pressures // similar share common ancestry// do not divergent evolution // convergent evo eg. pantadactyl limb // fins (whale, shark)

Question 43

how can molecular evidence be used for cladograms

Answer 43

related species = sequences with more similarities AA sequences accumulate diffs slower than DNA sequence