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IB Biology HL 2016 > Ch 5 > Flashcards

Ch 5 Flashcards

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1
Q

Evolution

A

The accumulative change in the heritable characteristics in a species over time

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2
Q

Evidence for evolution

A

fossil record
selective breeding of domesticated animals
homologous structures

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3
Q

fossil record

A
  1. fossils of organisms that no longer exist, yet are similar to present day organisms
    - implication: these fossil animals are ancient ancestors to modern day animals, thus modern day animals have changed over time
  2. sequence of fossils appear to match the sequence in which they would be expected to evolve
    - sequence also matches ecology with plant fossils appearing before animal
    - sequences of fossils are found which link modern day animals to their likely ancestors
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4
Q

selective breeding of domesticated animals

A
  1. people have developed domesticated animals with traits that they want by selecting which individuals are allowed to breed
    - implication: traits of offspring are related to traits of parents
  2. many more variations are possible than are actually seen “in the wild”
    - implication: variation is possible within a species
  3. changes seen in domesticated animals are due to selection: humans are choosing characteristics that they want and then breeding animals artificially to select for them
    - implication: selection can lead to evolution
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5
Q

homologous structures

A
  • structures that are similar in form but not always similar in function
  • pentadactyl forelimb
  • implication: these animals have similar bone structure because they descended from a common ancestor
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6
Q

comparison of pentadactyl limb of mammals, birds, amphibians and reptiles with different methods of locomotion

A
  • pattern of bones is the same in all these classes of animals, despite differences in locomotion
  • differences are seen in relative lengths of the different bones, but they all possess the same bones in the same arrangement
  • difficult to explain without the theory of evolution
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7
Q

speciation

A

if a population is divided and thus cannot interbreed (bc they are not located in the same place), different selective pressures can cause the groups to evolve and become different enough from each other that they can no longer interbreed
-new species forms

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8
Q

speciation: adaptive radiation

A
  • often happens when a species moves from one island to another and gets isolated from each other
  • ie. Hawaiian finches
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9
Q

continuous variation

A
  • if the change is gradual, we would expect to see lots of variety in the species, with intermediaries between the extremities
  • makes it very challenging to classify organisms (when are they different enough to be called different species?)
  • doesn’t match idea that species are distinct and not changing or that all individuals in a species are identical
  • implication: species are changing over time
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10
Q

ring species

A
  • as species spread across an area they sometimes wrap around geographic obstacles like mountains, forming a ring.
  • when the species meet on the far side of the mountain range, they can no longer reproduce together. They can, however, reproduce with the population that they most recently came from.
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11
Q

How did Darwin come up with his Theory of Natural Selection?

A

He went for a trip around the world

  • found fossils of animals that are no longer living
  • many living animals could not be found in the fossil record
  • found fossils of extinct animals that resembled living ones.
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12
Q

Galapagos islands

A

many animals are similar to animals from the mainland of South America, yet are different enough to be separate species

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13
Q

natural selection

A
  • there is variation in the population
  • there are more individuals than the environment can support
  • adaptations are characteristics that make an individual suited for its environment and way of life
  • the organism best suited for the environment will survive
  • the best adapted individual will also leave the most offspring
  • these offspring will also be adapted
  • increases the frequency of characteristics that make individuals better adapted and decreases the frequency of other characteristics leading to changes within the species
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14
Q

requirements for natural selection

A
  • variation among offspring
  • limited resources
  • some traits are more favorable for survival than others
  • favorable traits are passed on to offspring
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15
Q

outline the process of natural selection

A
  • sexual reproduction/mutation/meiosis produces variation in offspring
  • many more offspring are produced than can be supported by the environment
  • offspring must struggle and compete with each other to survive
  • offspring that are better adapted will survive, others will not
  • over time, the frequency of the adapted characteristics will increase in the population and the less adapted characteristics will decrease
  • species will change over time
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16
Q

variation is caused by…

A
  • sexual reproduction
  • mutation
  • meiosis
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17
Q

application: examples of evolution in response to environmental change

A
  • evolution of antibiotic resistance in bacteria
  • development of melanistic insects in polluted areas (peppered moths)
  • changes in beak shape in finches on Daphne major
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18
Q

why do we need to classify organisms?

A
  • 10 million species exist yet on 15% of all living species have been classified
  • helps us to organise
  • convenient
  • express degree of ancestral relationship
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19
Q

species

A

-a group actually or potentially interbreeding populations, with a common gene pool, which are reproductively isolated from other such groups

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20
Q

problems with the definition of species

A
  1. examples exist of “different species” that can breed in captivity
    - genetically, they can produce viable hybrids, they are separated by geography, not biology
  2. sibling species: cannot interbreed,but show no significant differences in appearance, therefore very difficult to identify (pipistrelle bat in Britain actually 2 different species of bats)
  3. makes it hard to name organisms that don’t reproduce sexually (bacteria)
  4. fossils cannot be classified according to biological definition of species as it is impossible to tell if they interbred
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21
Q

who was the father of modern taxonomy?

A

Carolus Linnaeus

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22
Q

binomial nomenclature

A
  • rules for giving an organism a scientific name
    1. naming and classification of organisms must be done in Latin language
    2. organisms must be named by two names
  • the 1st name must be of the genus
  • the 2nd name must be of the species
    3. the 1st letter of the genus must be in capital letter
    4. species name must be written in lowercase
    5. name must be underlined or italicized
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23
Q

advantages of using scientific names

A
  1. there is only one scientific name for each species
  2. there is a single species for each scientific name
  3. scientific names are recognized by scientists throughout the world
  4. today, scientific names are arranged by probably ancestry
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24
Q

natural classification

A
  • designed to classify organisms based on how they evolved
  • all members of a genus or higher taxon should have a common ancestor
  • since they evolved from a common ancestor, they have a lot in common
    (vs. classifying fish, sharks, and whales in the same group because they are all aquatic.)
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25
Q

the binomial system of names for a species is universal among biologists and has been agreed and developed at a series of congresses

A
  • congresses are official conferences held in which experts from around the world discuss how organisms should be classified
  • there are separate congresses for plants, animals and fungi
26
Q

how do we organise the millions of species into manageable groups?

A
  1. domain
  2. kingdom
  3. phylum
  4. class
  5. order
  6. family
  7. genus
  8. species
27
Q

list the domains

A

eukaryota
eubacteria
archaea

28
Q

list the kingdoms of eukaryotes

A

animalia
plantae
fungae
protista

29
Q

list the important phyla of the animalia kingdom

A 
chordata
arthropoda
mollusca
annelida
platyhelminthes
cnidaria
porifera
30
Q

list the classes of the chordata phylum

A 
mammals
reptiles
birds
amphibians
fish
31
Q

all animals…

A
  • cannot make their own food and usually acquire nutrition by ingestion
  • move by using muscle fibres
  • are multicellular
  • adult is usually diploid
  • usually reproduce sexually
32
Q

porifera

A
  • no mouth or anus
  • no symmetry
  • pores through their body
  • attached to a surface
  • ie. sponges
33
Q

cnidaria

A
  • mouth, no anus
  • radial symmetry
  • tentacles
  • stinging cells
  • ie. jellyfish
34
Q

platyhelminthes

A
  • mouth, no anus
  • bilateral symmetry
  • unsegmented
  • flat bodies
  • ie. tape worms
35
Q

annelida

A
  • mouth and anus
  • bilateral symmetry
  • bristles often present
  • segmented
  • earth worms
36
Q

mollusca

A
  • mouth and anus
  • muscular foot/mantle
  • soft bodied, usually with shell
  • segmentation not visible
  • octopus, snail
37
Q

arthropoda

A
  • mouth and anus
  • bilateral symmetry
  • segmented
  • jointed appendages
  • exoskeleton
38
Q

variation

A

differences in the phenotype of individuals of the same species

39
Q

selection pressures

A

environmental conditions that would favour one characteristic over another

40
Q

artificial selection

A

-humans choose the favourable characteristics before breeding an organism

41
Q

divergence

A

characteristics of two populations become less similar over time

42
Q

heritable

A

able to be passed down to offspring

43
Q

overproduction

A

more offspring born than can be supported by the environemnt

44
Q

adaptations

A

characteristics that make an individual suited to its environment

45
Q

inheritance

A

individuals that reproduce pass on characteristics to their offspring

46
Q

pentadactyl limbs

A

forelimbs with 5 “fingers’ of mammals, birds, amphibians and reptiles

47
Q

geographical range

A

the area a certain species inhabits

48
Q

mutation

A

random change in DNA

49
Q

sexual reproduction

A

reproduction requriing two gametes

50
Q

environment

A

abiotic and biotic conditions

51
Q

meiosis

A

reduction in the number of chromosomes to produce chromosomes

52
Q

how can the ancestry of groups of species be deduced?

A

by comparing their base or amino acid sequence

53
Q

clade

A
  • a group of organisms that have evolved from a common ancestor
  • each branch on the cladogram is called a clade
  • each clade includes a common ancestral organism and all its descendants
  • members of a clade share inherited characteristics
  • clades can be subsets of larger clades
54
Q

node

A
  • where the clade branches off
55
Q

what are clades based on

A

molecular analysis, genetic evidence, differences in amino acid sequences, DNA base changes or mutations

56
Q

what does the branch length of clades represent?

A

-branch length of clades can indicate relative amount of genetic change or time

57
Q

what determines branch separation?

A

fewest number of differences

58
Q

cladistics vs traditional classification

A

cladograms may not match traditional classification

-mismatch prompts reclassification of a group

59
Q

how are close relationships shown on a cladogram?

A

-close relationships are shown by a recent fork from the supporting branch; the closer the fork in the branch between two organisms, the closer is their relationship

60
Q

why is structure not always a good/accurate basis for classification?

A

-traits can be analogous or homologous

61
Q

analogous structures

A
  • structures that are similar between organisms because they perform the same function, but on closer inspection, they are revealed to be very different
  • different because they evolved from different ancestors
62
Q

reclassification of the figwort family

A
  • two small families were merged with the figwort family
  • many genera moved to another, existing family
  • some genera moved to a newly created family

IB Biology HL 2016 (6 decks)

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