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3.1 - classification Flashcards

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1
Q

why do we need an international classification system

A

-so that when scientists around the world are discussing a particular organism they have a way of making sure they are referring to the right organism
-by identifying the number of different organisms in a habitat scientist have a way of quantifying the biodiversity in that area
-it allows scientists to understand how different organisms are related to each other

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2
Q

before Linnaeus’ classification system was created, how were organisms classified into groups

A

-based on morphology
-organisms were classified into groups based on analogous (physically similar) features that didn’t always have the same-similar genetic origin

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3
Q

what is the order of taxonomic groupings

A

domain
kingdom
phylum (called division for plants)
class
order
family
genus
species

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4
Q

what are the 3 domains

A

archaea
bacteria
eukaryota

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5
Q

what kingdom comes after bacteria

A

eubacteria

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6
Q

what kingdom comes after archaea

A

archaebacteria

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7
Q

what are archaebacteria

A

-ancient bacteria thought to be the oldest form of living organism
-live in extreme conditions

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8
Q

what are eubacteria

A

-true bacteria
-include the bacteria that cause disease
-and useful in the digestive system

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9
Q

describe the kingdom protoctista
uni or multicellular
cellular structure
movement
nutrients acquired

A

unicellular
cellular structure: nucleus and membrane-bound organelles
movement: some can’t move, some have flagella and cilia
nutrients acquired: some are autotrophs they make their own food by photosynthesis, some are heterotrophs they eat other organisms

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10
Q

describe the kingdom plantae
uni or multicellular
cellular structure
movement
nutrients aquired

A

multicellular
cellular structure: nucleus, membrane-bound organelles, cell wall made of cellulose
movement: most don’t move, some gametes move by cilia or flagella
nutrients acquired: autotrophic, obtain nutrients through photosynthesis, store energy as starch

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11
Q

describe the kingdom fungi
uni or multicellular
cellular structure
movement
nutrients acquired

A

uni or multicellular
cellular structure: nucleus, membrane-bound organelles, cell wall made of chitin
movement: no mechanism for locomotion so reproduce through spores
nutrients acquired: heterotrophs, some are saprophytic meaning they feed on decaying materials, and some are parasitic meaning they obtain nutrients by feeding on a living host and harming it in the process

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12
Q

describe the kingdom animalia
uni or multicellular
cellular structure
movement
nutrients acquired

A

multicellular
cellular structure: nucleus, membrane-bound organelles
movement: cilia, flagella, contractile proteins
nutrients acquired: hetereotrophic, store energy as glycogen

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13
Q

what are the rules for using the binomial system

A

-the genus goes first and then the species
-the genus must have a capital first letter and the species must be lower-case
-must be written in italics
-after the binomial name is first used, it is abbreviated to the first letter of the genus and then the species name e.g. H. sapiens

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14
Q

what is the morphological species model
what are the limitations

A

-a model to define a species based only on the physical appearance of the organisms
-the appearance of a species can be effected by many environmental factors
-organisms which show sexual dimorphism have very different physical appearances and wouldn’t be though of as the same species

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15
Q

what is the widely used definition of a species

A

a group of organisms with similar characteristics that interbreed to produce fertile offspring

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16
Q

what is an advantage of using the reproductive/biological species concept

A

-organisms of different species may look similar if adapted to survive in the same environment
-it overcomes the issue of sexual dimorphism

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17
Q

what are the limitations of the reproductive/biological species concept

A

-new species are found that haven’t been observed matting, breeding programmes are expensive and time-consuming
-plants of different but closely related species frequently interbreed to produce fertile hybrid offspring
E.g. lions and tigers can breed, most of the offspring are fertile
-some organisms don’t reproduce sexually
-it is hard to classify fossil organisms because they cannot reproduce
-not all the organisms within a species interbreed, this may be because they are in different geographical places

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18
Q

what is DNA sequencing

A

a process where the base sequences of all or part of the genome of an organism are worked out
DNA sequencing leads to DNA profiling

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19
Q

what is DNA profiling

A

a process where the non-coding areas of DNA are analysed to identify patterns
these patterns are unique to individuals but the similarity between patterns can be used to create links between organisms

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20
Q

what is bioinformatics

A

the development of computer tools and software which organise and analyse raw biological data from DNA profiling and DNA sequencing
it looks for patterns between the data of different organisms, to identify if they are from the same species and determine evolutionary relationships
because it would be impossible for 1 scientist to process all this data

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21
Q

what are DNA barcodes

A

-it involves looking at short genetic sequence common to all the organisms within the species
-DNA barcodes are unique to each species
-DNA barcodes can be used to identify which species an organism belongs to

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22
Q

how does DNA profiling give information about evolutionary links

A

-the more mutations there are in the DNA between different organisms, the longer the time since they shared a common ancestor -an average mutation rate is used to estimate how long ago that common ancestor lived
-however there are limitations
-the rate at which DNA mutates can vary
-DNA fragment start to degrade immediately after death, so have to be kept in specific conditions to be preserved

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23
Q

how can fossils be used to determine evolutionary relationships within human evolution

A

-scientists can extract DNA from suitable fossils
-and analyse them with DNA sequencing and DNA profiling

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24
Q

explain how scientists validate new evidence

A

-when a piece of research produces useful results and conclusions it is submitted to a scientific journal
-this article will then go through a process of peer review where it is read by several scientists to see if the evidence is reliable
-the article should contain enough information for other scientists to carry out similar investigations to determine if the conclusions can be validated
-scientific conferences may be held where scientists working in the same field get together to talk about new evidence
-providing the opportunity to challenge the validity of results being presented and for the development of new techniques in research

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25
explain how to conduct gel electrophoresis
-place either DNA fragments, RNA fragments, amino acids or proteins in wells inside an agarose plate -if DNA is used: restriction endonucleases cut the DNA molecule into fragments -because the order of bases in different organisms DNA is different, DNA from different organisms will be cut into different lengths -the DNA fragments are dyed which fluoresces when places under UV light and the dye moves faster than DNA fragments (so the current can be turned off before all the DNA fragments reach the positive terminal) -an electric current passes through the agarose plate -DNA fragments start at the negative electrode and move towards the positive electrode, because DNA molecules are negatively charged due to the negative phosphate group -smaller DNA fragments move faster and further along the gel, so smaller fragments are found close to the positive electrode and larger fragments close to the negative electrode -once electrophoresis is complete the agarose plate is placed under UV light -DNA fluoresces so the pattern of the bands can be identified
26
when electrophoresis is used to identify and compare amino acids, is a dye added
no ninhydrin is added to the agarose plate after electrophoresis it reacts with the amino acids so they show up as purple patches
27
what evidence can be used to determine evolutionary relationships ONGOING
-all organisms in a species contain the same type of blood pigment -organisms of the same group share the same sequence if amino acids in particular proteins
28
what is the endosymbiosis theory of mitochondria and chloroplasts
-that mitochondria and chloroplasts once existed as their own prokaryotic organisms -a eukaryotic cell (can only respire anaerobically) engulfs an aerobic prokaryote (mitochondria) as food -O2 levels in the atmosphere rise, for some cells it is toxic and others can tolerate it -by chance in some cells the prokaryotic cells isn't digested, it respires aerobically providing the cell with more efficient energy to grow -the eukaryote becomes permanently present in the cell and copies are made and passed to daughter cells -this new eukaryotic cell engulfs a photosynthetic organism (chloroplast) as food -by chance it isn't digested -it photosynthesises providing the eukaryotic cell with food allowing it to grow more efficiently -the chloroplast becomes a permanent feature and passed down to offspring
29
what are the 3 domains
bacteria archaea eukaryota
30
out of bacteria, archaea and eukaryota which 2 are most closely related
eukaryota and archaea
31
why are some reasons the 2 domain system was removed and the 3 domain system introduced
-archaea replicate through binary fission within a controlled cell cycle -this is more similar to how eukaryota reproduce also within a cell cycle -and very different to how bacteria divide -archaea have unique membrane structures and membrane proteins -archaea membrane lipids are branched -bacteria and eukaryota membrane lipids are unbranched
32
state the names of the kingdoms
-archaebacteria -eubacteria -protoctista -fungi -plantae -animalia
33
describe the process of natural selection by survival of the fittest
-organisms that reproduce sexually show variation in their phenotype -organisms produce an excess of offspring -selection pressures, such as a new disease or limited food, mean that organisms with advantageous characteristics survive and reproduce -they pass the advantageous characteristics down to their offspring -this process repeats over many generations
34
what is evolution
the long term changes in the genetic composition of a population of organisms over several generations, as a result of natural selection, bringing about new adaptations or sometimes new species
35
what is a niche
the role of the organism in the community
36
what are the 3 types of adaptations
anatomical physiological behavioural
37
what is the definition of anatomical adaptations
adaptations involving the form and structure of an organism
38
what is the definition of physiological adaptations
adaptations which involve the way the body of the organism works and include differences in biochemical pathways or enzymes
39
what is the definition of behavioural adaptations
adaptations involving changes to programmed or instinctive behaviour making organisms better adapted for survival
40
what is the definition if directional selection
natural selection showing a change from 1 dominant phenotype in the population to another phenotype in response to a change in environment e.g. the change from most moths in the population in industrial cities being light to dark
41
what is the definition of a selection pressure
changes in the environment/niche of a population, causing natural selection, leading to changes in the phenotype of that population
42
what are some factors that contribute to the antibiotic resistance problem
-antibiotics are too widely prescribed and used -wide-spectrum antibiotics are often used to make sure they cure the infection, rather than running tests to determine in the infection is bacterial and which bacteria are involved -people don't complete the course of antibiotics -antibiotics are commoly used in the food chain
43
what are some measures taken to overcome antibiotic resistance
-reducing use of antibiotics -reducing use of antibiotics in farm animals -DNA sequencing will help identify bacteria and find new ways of targetting them, then genetic engineering can be used to produce large amounts of new drugs -development of new antibiotics
44
what is speciation what causes speciation
-speciation is the formation of a new species -2 groups in a population become separated and experience different conditions -the 2 groups undergo natural selection so over time the phenotype and genotype of these 2 groups changes -it reaches a point where if the 2 groups are reunited they cannot interbreed -so they have become 2 separate species
45
how does speciation occur from hybridisation
-2 closely related species can interbreed to produce fertile hybrids -these hybrids sometimes can go on to produce offspring and may be better adapted to their niche -if the hybrid cannot breed with the same species as the parent organism, the hybrid and parent organism are 2 different species
46
state the 5 reproductive isolation mechanisms for speciation
geographical isolation ecological isolation seasonal isolation behavioural isolation mechanical isolation
47
describe geographical isolation
a physical barrier separates individuals from an original population
48
describe ecological isolation
2 species inhabit the same region but develop preferences for different part of the habitat
49
describe seasonal isolation
the time of flowering or sexual reproduction in some parts of the population can shift away from the normal time of the population, eventually leading to the 2 groups reproducing months apart
50
describe behavioural isolation
some individuals in the population change their mating display or pattern, causing the rest of the population to not recognise them as potential mates, so won't reproduce with them
51
describe mechanical isolation
a mutation occurs that changes the genitalia in animals or the relationship between the stigma and stamens in flowers of some individuals in the population, so it is physically impossible for them to reproduce with the rest of the population
52
what is allopatric speciation
takes place when populations are physically or geographically separated and there can be no interbreeding or gene flow between these populations
53
what is meant by endemic
an endemic species is a species that evolves from geographical isolation and can only be found in one place so an endemic species forms as a result of allopatric speciation
54
what is adaptive radiation
when one species evolves rapidly to form many other different species, which all fill diferent ecological niches usually occurs after allopatric speciation
55
what is sympatric speciation
takes place between populations of a species living in the same area that become reproductively isolated due to mechanical, behavioural, or seasonal changes gene flow continues to some extent between the populations as speciation occurs
56
what is the definition of biodiversity
the variety of life on earth, including genetic diversity between individuals in a species and between different species, and the variety of different ecosystems
57
why is it important to maintain biodiversity
-the food chain will be more stable because populations will be more stable and resilient -air and water is purified by the actions of organisms -photosynthesis releases water which stabalises the atmosphere and earth's climate -plant roots stabalise soil -new medicines
58
what is a biodiversity hotspot
an area with particularly high levels of biodiversity
59
what is species richness
the number of different species in an area
60
what is an endemic species
a species that is only found in that area no where else
61
why do some areas have more endemic species than others, what are some criteria for endemic species to arrise
-stable ecosystem allows complex relationships to develop between species -high levels of photosynthesis can support more niches -areas where organisms can rapidly grow and reproduce mean that it is more likely that mutations occur, leading to adaptations which exploit more niches
62
why is relative species abundance important to take into account when determining biodiversity
-2 areas may have the same number of species -but in area A 2 of those species dominate -whereas in area B there is an even split between the number of organisms from each species -area B has greater biodiversity
63
what are some of the ethical reasons for maintaining biodiversity
-if we destroy ecosystems we are denying future generations the opportunities to use these renewable natural resources -biodiversity within the natural world is a source of pleasure for many people
64
what is 1 economical reason to maintain biodiversity
Ecosystem services: -services that are provided by the natural environment that benefit people -the main categories are: Provisioning services - Ecosystems provide us with food, building materials, fuel. The greater the biodiversity the more sources of services we will have. Regulating services - ecosystem processes help to regulate our environment through purifying water, sewage treatment and maintaining the climate of the planet. Supporting services - Plants stabalise soil and support nutrient cycling which allows us to grow crops for food Cultural services - ecosystems provide tourism which generates money
65
what is ex-situ conservation
the conservation of living organisms outside of their natural habitat
66
what is in-situ conservation
the conservation of organisms of an endangered species within their natural habitats, and the conservation of ecosystems and natural habitats
67
what are some examples of ex-situ conservation sites
botanic gardens, zoos, seed banks
68
what are some limitations of ex-situ conservations
-there's not enough space in zoos for all endangered species -because the population size is small the gene pool is reduced -reintroduction programmes are expensive, time consuming and can fail because animals lose their natural instinctive behaviours -reintroduction programmes will be unsuccessful unless the reason the species is endangered is removed
69
an example of an in-situ conservation site
national parks
70
examples of in-situ conservation techniques
habitat restoration and recovery sustainable use and management of biological resources sustainable farming techniques like biological pest control and organic fertilisers selective logging
71
what are some limitations of in-situ conservation
-large areas of land need to be protected which can take away land for housing and farming -maintaining the land costs a lot of money which can instead be used for education and healthcare
72
do bacteria and archae have nueclei
no
73
Explain the evidence that led to the three-domain model of classification replacing the five-kingdom model. (3 marks)
-molecular phylogeny techniques were discovered such as DNA sequencing and DNA profiling -which found similarieties and differences between archae and bacteria -such as that archaea have unique membrane proteins and membrane structures that are different to bacteria and eukaryotes -archaea have branched membrane lipids whereas bacteria and eukaryotes have unbranched membrane lipids
74
Give a method that a scientist, with a new theory based upon experimental results, could use to share this with others in the scientific community. (1 mark)
peer reviewed scientific journals scientific conferences
75
Explain why gel electrophoresis produces individual DNA profiles. (2 marks)
-the sequence of bases that make up is different for each person -so when endonuclease enzymes cut the DNA molecules, they will produce DNA fragments of different lengths
76
Describe the information scientists can use to classify an organism as a new species.
-it cannot reproduce with other organisms to produce fertile offspring -compare its anatomy -use DNA profiling and gel electrophoresis -observe its behaviour and which niche it occupies
77
Explain why it may be difficult to classify a newly discovered organism as a separate species. (2 marks)
-haven't observed the organism interbreeding to produce fertile offspring -there is variation withing the species due to sexual dimorphism -species are constantly evolving so new physical characteristic may emerge due to new adaptations
78
what are the similarities and differences between allopatric and sympatric speciation
similarities: -both experience reproductive isolation -both there is an original population -absence of gene flow -if the 2 groups are brought together they will not reproduce to form fertile offspring differences: -in allopatric there is a physical barrier separating the 2 groups -in sympatric the 2 groups live in the same habitat but are separated by reproductive, ecological, anatomical, physiological isolation
79
Explain the difference between biodiversity within a habitat and biodiversity within a species. (2 marks)
biodiversity within a habitat is the number of different species within a habitat and species evenness biodiversity within a species is the genetic variation between organisms in 1 species
80

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