Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

HL Biology - topical sets > Topic 5 > Flashcards

Topic 5 Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

Define evolution [1]

A

cumulative changes in the allele frequency of a population’s gene pool over successive generations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

define fossil

A

preserve remains or traces of an organism from the remote past

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

how fossils provide evidence for evolution

A
  • preserved remains provide direct evidence for evolution, incl/ teeth, bones, etc.
  • traces provide indirect evidence for evol and incl/ footprints, tooth marks, etc.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

define the fossil record

A

the totality of all fossil, both discovered and undiscovered. it shows that over time, changes have occurred in the living organisms’ features

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

fossil dating

A
  • the fossil can be dated by determining the age of the strata/rock layer it was found in
  • fossils develop in sedimentary rocks -> lower layers form before upper layers
  • various organisms found in a particular order in rocks of different ages:
    • prokaryotes before eukaryotes
    • ferns before flowering plants
    • invertebrates before vertebrates
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Law of fossil succession

A

chronological sequence of complexity by which characteristics seem to develop. the law of succession indicates that new organisms formed from changes to older organisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

limitations of the fossil record

A
  • record is incomplete –> don’t have all the fossils to clearly see evolutionary changes
  • fossils require specific conditions to form -> not all organisms fossilise
  • only hard parts of organisms preserved -> only fragments of organism fossilised
  • with limited fossil data, difficult to discern evol. pathways -> missing links
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

transitional fossils

A
  • intermediary forms that occur over the evolutionary pathway of a single genus
  • displays characteristics shared by ancestor and descendant
  • eg:- archaeopteryx -> links evolution of dinosaurs to birds
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

example of how fossils used as evolutionary evidence

A

australopithecus skeletons compared to homo sapiens skeleton to see evolutionary changes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Selective breeding

A

a form of artificial selection by which man breeds organisms with desired traits, increasing the frequency of the trait in population

  • provides evidence for evolution as offspring show large amount of variation in a short span of time
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Selective breeding examples

A
  • used to produce new types of crops. Brassica genus selectively bred to produce broccoli (modified flower buds), kale (modified leaves)
  • horse: different types of horses bred for different functions. Race horse -> speed, hence bred to be leaner, lighter taller. draft horses for power and endurance -> sturdier, heavier
  • dogs: dogs with different qualities bred for various functions
  • cows: selectively bred for improved milk production. increased breeding of cow w a mutation that causes it to have increased muscle mass (belgian blue)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Homologous structures

A
  • structures that are similar in basic structure, despite being used in different ways
  • evidence of adaptive radiation, where new species rapidly diversify from the ancestral source, which each species utilised a specific, unoccupied niche
  • the more similar the HSs are, the closer organisms are likely to be

Eg: - pentadactyl limb
- the 5 digit limb with a similar arrangement of bones
- in humans -> used for gripping and holding, in birds -> used for flying, in horse hooves -> galloping, whale/dolphin fins -> swimming

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

speciation process

A
  • there is variation in a population and it often follows a continuous normal distribution curve
  • if 2 populations are geographically separated, they begin to adapt to their different environments, and diverge from one another
  • with increased time, separated populations faced increased divergence, and lowered genetic compatibility. if the populations diverge to the extent where they cannot interbreed when put in same environment -> separate species
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

speciation definition

A

the evolutionary process by which 2 related populations diverge into separate species

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

5 processes of natural selection

A
  • variation: variation exists between members of a population -> can be inherited
  • competition: lower resources for pop -> struggle for survival
  • selection: differential reproduction occurs due to env selection pressures
  • adaptations: organisms with beneficial traits more likely to pass on to offspring
  • evolution: over time, there is change in allele freq. in gene pool
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Explain how natural selection can lead to speciation

A
  • variation is required for natural selection
  • as a result of mutation/sexual reproduction
  • there are more organisms than environment can support/competition
  • adaptations make organisms more suited to their environment
  • survival of better adapted individuals
  • organisms with beneficial traits are more likely to survive and pass on traits to offspring
  • speciation is the formation of a new species from one population
  • reproductive isolation of separated populations
  • geographical isolation can cause it
  • temporal/behavioural isolation can cause it
  • natural selection within 2 separated populations causes them to diverge from one another -> speciation
  • disruptive selective often separates 2 populations
  • changes in gene pools of separated populations
  • 2 populations cannot interbreed to produce fertile, viable offspring
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

describe the changes that occur in gene pools during speciation [5]

A
  • gene pool is all the genes/alleles in an interbreeding population
  • the gene pools splits when the popualtion splits
  • due to reproductive isolation of groups within species
  • due to behvioural/temporal isolation between species
  • natural selection causes gene pools of the 2 groups to gradually diverge
  • diverge of gene pools
  • allele frequencies change
  • different random mutations occur in each population -> more divergence
  • until the populations cannot successfully interbreed
18
Q

Outline evidence for evolution provided by selective breeding [3]

A
  • crop/plants/livestock animals produced by selective breeding
  • eg- new varieties of plants like broccoli and kale produced by growing modified varieties of the Brassica genus. Cows with increased milk production/ Belgian blues with more muscle mass bred for meat and milk
  • evidence as show a rapid change in characteristics over s short period of time
  • changes due to selective breeding show that natural selection can cause changes/evolution in species
19
Q

How genetic variation between individuals in a species can be generated [7]

A
  • mutations
  • base substitution
  • can cause various alleles for a particular gene
  • radiation/mutagens increases chances of mutations
  • meiosis
  • sexual reproduction -> random fertilisation and fusion of 2 gametes
  • independent assortment -> due to random orientation, 2^n ways in which the chromosomes can be sorted
  • crossing over of genes in P1 -> creates recombinants, increases variation
  • in reproductively isolation populations nat selection may differ
  • in small/isolated populations gene pools change
  • disruptive selection can cause different varieties to diverge
20
Q

competition

A
  • malthusian dilemma -> population grows geometrically while food grows arithmetically
  • stable population will outgrow its food base
  • more offspring than the environment can support -> environmental resistance
  • struggle for survival, increased mortality rate
21
Q

5 types of adaptations

A
  • structural: physical differences in biological structure (eg length of giraffe neck)
  • biochemical: differences in the molecular composition of cells and enzyme functions (eg blood groups)
  • behavioural: differences in organisms patterns of activity (eg possums faking death when threatened)
  • physiological: variations in detection and response by vital organs (eg colour perception)
  • developmental: varibale changes occurring across the organism’s lifespan (eg ageing patterns)

since biological adaptations have a genetic basis -> can be inherited

22
Q

Adaptive radiation

A
  • The rapid evolutionary diversification of a single ancestral line. when organisms of a single species occupy various environmental niches and develop morphological characteristics in response to various environmental selection pressures. eg :- finches on galapagos islands have different beak shapes -> different foods
23
Q

Daphne Major birds

A

Darwin’s finches on the Galapagos islands. they have a variety of beak sizes and shapes adapted to their varied diets -> larger beaks for those which fed on larger seeds with tougher casings

one year there was drought -> increased seeds with tougher casings. more finches had larger beaks -> finches with larger beaks more likely to reproduce that year -> natural selection

24
Q

Benefits of binomial naming system

A
  • easy to identify and compare organisms based on recognisable characteristics
  • allows evolutionary links between organisms to be recognised -> how closely related organisms are
  • easy to collect, sort and store info about organisms
  • a globally recognised scheme for identifying and naming organisms
25
Q

What are the domains of life

A
  • Eubacteria: prokaryotic cells, lack compartmentalisation and membrane bound nucleus -> consist of common pathogenic forms
  • Archaea: prokaryotic cells that lack nucleus and are extremophiles -> eg thermophilic bacteria
  • Eukarya: eukaryotic organisms containing a membrane bound nucleus
26
Q

define taxonomy

A

the classification of organisms into groups based on shared characteristics. they are grouped according to series of hierarchal taxa

  • the more taxa organisms share the more closely related they are (KPCOFGS)
27
Q

Describe artificial classification

A
  • organisms grouped together based on the similarity of characteristics -> analogous traits
  • doesn’t consider whether they have evolved from same ancestors -> brings together dissimilar species
  • A: easy schemes to develop, unlikely to change
28
Q

Describe natural classification

A
  • when organisms are grouped together based off of common ancestry -> identifying similarities then identifying shared characteristics
  • more often used because it allows for evolutionary links to be seen and allows for prediction of characteristics shared by species
  • DA: Highly mutable -> change as new info discovered
29
Q

phylogenetic classification

A
  • newer type
  • organisms with greater amount of homology in their DNA/AA sequences for common genes/proteins -> closer together
30
Q

Example of changes in natural classification

A
  • species originally classified as figworts were then classified as a different genera based on new evidence indicating different ancestry
  • chimpanzees and gorillas were added to the Homininae sub-family upon new evidence suggesting shared ancestry with humans than other great apes
31
Q

what is a dichotomous key

A
  • a graph that keeps dividing into 2 categories, until the organisms doesn’t share totality of selected characteristics anymore -> it has been identified
  • with each division, more specifc info about organism is revealed
  • types of featured used: biological processes or physical characteristics that aren’t subject to change
32
Q

Define cladistics

A

the practice of classifying species into groups called clades

33
Q

Define clade

A

An ancestral organism and ALL its evolutionary descendants

34
Q

What are cladograms

A
  • tree diagram
  • each branch point/node represents a speciation event -> divergent evolution took place -> 2 distinct species formed from a common ancestor
  • allows for the likely evolutionary history of a clade to be mapped
  • fewer nodes between 2 groups -> more similar they are

according to cladograms, chimpanzees, gorillas, humans, orang-utans and gibbons are part of the Hominoid clade. hominoid clade is part of a larger clade -> anthropoids

35
Q

features of cladograms

A
  • root: the original ancestor common to all the organisms in the clade
  • node: the hypothetical ancestor that speciated to give rise to 2 or more daughter taxa
  • outgroup: the species that is the most distantly related. functions as the point of comparison and reference group
  • clade: a common ancestor and ALL of its descendants
36
Q

Ways to create cladogram

A

Structural features:
- use structural organism features that aren’t subject to environmental pressure -> eg hair, amniotic egg, number of limbs, etc.
- sequentially order organisms according to shared characteristics

Molecular evidence:
- use genbank or other software to find DNA or AA seq for certain proteins/genes shared by all org -> eg cytochrome c
- run software to see which organisms aa seq has the most simialrity

37
Q

How molecular evidence works + types of evidence used for different purposes

A
  • mutations in the gene/dna/aa sequences accumulate over years
  • aa can be compared due to the universal genetic code, dna can be compared for comparable base sequences
  • more similar the sequences are -> lesser time has passed since the species diverged
  • Non coding DNA: highest mutation rate-> best means of comparison -> mutations will occur more readily
  • coding dna: slightly lower mutation rate -> mutations would result in altered proteins structures
  • AA seq: lowest mutation rate -> degenerate code. used to compare organisms that are very distantly related
38
Q

Molecular clock concept + limitations

A
  • some proteins/gene sequences mutate at a fairly constant rate. if the rate is reliable -> one can estimate how long ago divergence took place

limitations:
- the rate of mutation may vary between different organisms
- later mutations may ‘undo’ or reverse earlier mutations -> lowers the accuracy
- different genes/proteins may mutate at different rates

39
Q

Convergent evolution

A

the independent evolution of similar structural features in species with distinct lineages

  • organisms may occupy same habitat -> subjected to similar selection pressures
  • features that benefit survival in the environment differentially selected
40
Q

Analogous vs homologous traits

A

Analogous:
- traits that are superficially structurally similar but derived through separate evolutionary pathways
- due to convergent evolution
- used in artificial classification -> brings together dissimilar species

Homologous:
- traits that are similar as they have been derived from a common ancestor but have developed to be used in different functions
- pentadactyl limb
- due to divergent evolution/adaptive radiation
- natural classification is based on homologous -> predictive values/matches evolutionary history

41
Q

Reclassification of figworts

A
  • figworts were the 8th largest family of angiosperms
  • many figwort species were too dissimilar
  • genetic analysis was conducted of chloroplast gene
  • figworts split into 5 different clades

HL Biology - topical sets (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions