Chapter 10 - Flashcards
(119 cards)
1
Q
what is a dichtomous key?
A
- D Literal meaning = ‘to cut in two’
- This involves using a series of questions, each of which divides the group into two groups and so on
2
Q
what is classfication?
A
The grouping together of organisms
3
Q
what is taxonomy?
A
The science of classification
4
Q
what is a taxon?
A
A group of similar organisms
5
Q
why do scientists classify organisms using one, worldwide system?
A
by using a single classification system, scientists worldwide can share their research. Links between diff organisms can be seen even if these are on a diff continent
6
Q
how many taxonomic groups are there?
A
7
7
Q
what are the taxonomic groups?
A
Kingdom Phylum Class Order Family Genus Species
8
Q
mnemonic to remember the taxonomic groups?
A
Kids Prefer Chips Over Fancy Green Salads
9
Q
what is a hiercachy?
A
a system in which members of an organisation or society are ranked according to relative status or authority
10
Q
what forms the binomial name of an organism?
A
the genus and species
11
Q
who devised the system of binomials?
A
Linneaus, which greatly simplified the description of species at the time.
12
Q
rules for binomial naming?
A
- Genus must be capitalised
- species must start w a lower case letter
- must be written in italics or underlined if handwritten
13
Q
the 5 kingdom system?
A
Traditionally, Linnaeus’ system has been used to classify species.
This divides all organisms into 5 large groups called KINGDOMS
14
Q
what are the traditional 5 Kingdoms?
A
- Prokaryotae
- protoctista
- fungi
- plantae
- animalia
15
Q
mneoumonic to remember traditional 5 kingdoms?
A
- Please
- Pass
- Freshly
- Painted
- Apples over
16
Q
Prokaryotae description?
A
- Unicellular & microscopic
- No nucleus or other membrane bound organelles - a ring of ‘naked’ DNA - small ribosomes
- Cell wall made of murein.
- No visible feeding mechanism - nutrients are absorbed through the cell wall or produced internally through photosynthesis
- Examples: Bacteria or Cyanobacteria (photosynthesising bacteria)
17
Q
Protoctista description?
A
- (mainly) unicellular
- A nucleus and other membrane bound organelles
- Some have chloroplasts
- This is usually the kingdom where organisms which aren’t animals, plants or fungi go.
- Examples: Algae, slime moulds and the malaria causing Plasmodium.
- Some are sessile but others move by cilia, flagella, or amoeboid mechanisms
- Nutrients are acquired by photosynthesis (autotrophic feeders),ingestion of other organisms (heterotrophic feeders) - or both some are parasitic
18
Q
Fungi description?
A
- Unicellular or multicellular
- A nucleus and other membrane bound organelles and a cell wall mainly composed of chitin
- No chloroplasts or chlorophyll
- No mechanisms for locomotion
- Most have a body or mycelium made of threads or -hyphae
- Nutrients are acquired through absorption - mainly from decaying material - they are saprophytic feeders - some are parasitic
- Most store their food as glycogen
- e.g. Mushroom, mould, puffball
19
Q
Plantae description?
A
- Multicellular
- A nucleus and other membrane bound organelles including chloroplast and a cell wall mainly composed of cellulose
- All contain chlorophyll
- Most do not move, although gametes of some plants move using cilia or flagella
- Nutrients are acquired by photosynthesis - they are autotrophic feeders - organisms that make their own food
- Store food as starch
20
Q
Animalia description?
A
- Multicellular
- A nucleus and other membrane bound organelles (no cell walls)
- No chloroplasts
- Move with the aid of cilia, flagella, or contractile proteins, sometimes in the form of muscular organs
- Heterotrophic feeders - nutrients acquired by ingestion
- Can be split into 2 groups: vertebrates and invertebrates
- Food stored as glycogen
21
Q
classification systems are continually changing as?
A
scientists discover new evidence and new techniques.
22
Q
nowadays, classification is based more on?
A
biochemical and molecular evidence - especially comparisons between DNA base and protein amino acid sequences.
23
Q
why did the traditional 5 kingdom system come under some critisism?
A
- in the light of new evidence, mainly differences in ribosome and RNA polymerase structure.
- Differences were observed between members of the prokaryotic kingdom that led scientists to believe that this kingdom should actually form two distinct groups.
24
Q
how did the new system introduced differ from the traditional 5 kingdom classification system?
A
A new system was proposed, introducing domains as a further level of classification at the top of the hierarchy.
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what are the 3 domains?
- Bacteria (Kingdom prokaryotae was split into 2 domains- B & A)
- Archaea
- Eukarya (the 4 eukaryotic kingdoms were grouped together into 1 domain)
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what does the new classification system consist of?
- 3 domains, 6 kingdoms
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what is classification into the new system based on?
- features such as differences in RNA polymerase structure and ribosome size.
- RNA polymerase is actually not a single protein, but a collection of different proteins working together.
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what are the 6 kingdoms in the NCS?
- Eubacteria
- Archaebacteria
- Protoctista
- Fungi
- Plantae
- Animalia
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what does the NCS do better?
- better represents the phylogenetic relationships between the different taxa.
- The closer the branches on the diagram, the more closely related/similar those groups are
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what is phylogeny?
- Phylogeny is the concept of evolutionary relationships.
| - Modern classification is based on phylogeny rather than observable features.
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what is evid abt phylogenetic relationships used to build up?
Evidence about phylogenetic relationships is used to build up a ‘tree of life’ showing common ancestors, speciation events and extinctions. Darwin drew the first one.
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Evolution is based on the idea of ?
- common descent.
- ~3.5 billion years ago there was a ‘universal common ancestor'
- Since then, natural selection has caused 3 things to happen: Speciation, Anagenesis, Extinction
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what is Speciation?
the formation of new species
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what is Anagenesis?
changes within species
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what is Extinction?
loss of species
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Evolution definition?
“The development of new types of organism from pre-existing types by the accumulation of genetic differences over long periods of time.”
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what did Wallace do?
- Jointly published a paper with Darwin in 1858, putting forward the theory of natural selection
- travelled extensively, discovered the ‘Wallace Line’, a line separating the organisms of Asia and Australia.
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what did Lamarck do?
proposed that the stretching of the giraffe’s neck to reach the leaves at the tops of trees was inherited by its offspring.
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What is the problem with Lamarck's theory?
Acquired characteristics cannot be passed on to the next generation. You don’t inherit your parents’ tattoos!
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organisms evolve due to?
natural selection.
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how does natural selection work?
- there r selection pressures
- intraspecific variation caused by diff allele combinations
- this leads to an organism being poorly adapted, selective -, selected against, dead, or better adapted, selective +, selected for, survive
- selected for organisms goes onto reproduce & passes allele combinations on to offspring
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organisms are ? for the envir in which they live?
adapted
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Adaptations can be?
Anatomical
Behavioural
Physiological
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Anatomical adaptations?
- physical features, internal and external e.g. Teeth - the shape & type of teeth present in an animal's jaw are related to its diet, Camouflauge - making it harder for predaator to spot it
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Behavioural adaptations?
- the way an organism acts
- e.g. survival behaviours - rabbit freezes when thinks its been seen
- e.g. courtship - many animals exhibit elaborate courtship behaviours to attract a mate - scorpions perform a dance to attract a partner
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Physiological adaptations?
- processes that take place within an organism
| - e.g. poison production -
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Physiological adaptations?
- processes that take place within an organism
- e.g. poison production - many reptiles produce venom to kill prey and plants posion to avoid being eaten
- Antibiotic production - some bacteria produce antibiotics to kill other species of bacteria in the the surrounding area
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what is convergent evolution?
Convergent evolution takes place when unrelated species begin to share similar traits.
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what are analagous structures?
are adapted to perform the same function but have a different genetic origin
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what has provided evid for convergent evol?
anatomical adaptations
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what are marsupials?
- endemic to Australia & the Americas. Most of the young are carried in a pouch.
- any members of the mammalian infraclass Marsupialia
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plants that show convergent evolution?
- aloe and agave appear similar as have both adapted to survive in the desert but have developed entirely seperately.
- Aloe= evolved in sub-Saharan Africa
- Agave = mexico
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modern examples of evolution - human influences?
- Antibiotic resistant bacteria
- pesticide resistant insects
- plastic digesting bacteria
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antibiotic resistant bacteria - e.g. + description?
- e.g. = MRSA
- bacteria reproduce v rapidly and so evolve in a relatively short time
- when bacteria replicate, their DNA can be altered and this usually results in the bacteria dying
- hwvr, a mutation in some S. aureus arose that provided resistance to methicillin
- when the bacteria were exposed to methicilin, resistant indivs survived and reproduced passing the allele for resis onto offspring
- non resistant indivs died and overtime the no. of resistant ⬆
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pesticide resistant bacteria - e.g. + description?
- e.g. = Sheep Blowflies
- in 1950s in Australia, the pesticide diasion was used to kill the blowflies and prevent 'flystrike'
- within 6 years, blow flies developed a high level of resistance to diazonin
- indiv insects w resistance survived exposure to the insecticide and passed on this characteristic thru their allelles, allowing a resistant pop to evolve
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plastic digesting bacteria - e.g. + description?
- e.g. = Flavobacterium
- some organisms have evolved due to opportunities that have arisen in their envir
- new strain of Flavobacterium live in waste water from factories that produce Nylon 6
- evolved to digest nylon and is thr beneficial to humans as help to clean up factory waste
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evolutionary Embryology?
Embryos of many diff animals look similar and it is often diff to tell them apart ➡ shows animals develop in a similar way, implying that the process of embryonic development have a common origin.
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who propsed the 3 Domain sustem?
Carl Woese. Organisms grouped using differences in the sequences of nucleotides in the cell's ribosomal RNA( rRNA), cell membrane's lipid structure and their sensitivity to antibiotics
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why were Eubacteria classed in their own kingdowm?
bc their chemical makeup is diff from Archaebacteria
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ribsosomal diffs between eukarya, archae, and nacteria?
- Eukarya:80s & 12 proteins in RNA polymerase,
- Archaea :70s & diff organisms contain 8-10 & very similar to Euk ribosome
- bacteria:70s & 5 proteins in RNA polymerase
61
Wallace & Darwin
- Darwin studied e.g. finches on the Galapagos Islands to come up with the theory of NS
- at the same time, Alfred Wallace was working on his own theory of evolution
- their ideas were so similar that they jointly published a paper on NS to the Linnean society
62
Palaentology?
- within diff stratas of rock, the fossils found are quite diff, forming a sequences from oldest ➡ youngest, which shows that organisms have gradually changed over time - fossil record
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evidence provided by Palaentology in terms of age of the rocks? (fossils)
- oldest rocks: fossils of simplest organisms e.g. bacteria,
- recent rocks: more complex organisms e.g. vertebrates
➡ supports evol theory that simple life forms gradually evolved over a long period of time to more complex ones.
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evidence provided by Palaentology? (sequence found)
the seq in which organisms are found matches their ecological inks to each other e.g. plants b4 animals ➡ animals require plants to survive
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evidence provided by Palaentology? (similarities)
by studying similarities in the anatomy of fossil organisms, scientists can show how closely related organsisms have evolved from the same ancestor (e.g. Zebra, horses, rhinos)
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evidence provided by Palaentology? (relationships)
fossils allow relationships between extinct and living organisms to be investigated
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limitation of Palaentology?
the fossil record is not complete e.g. soft boded organisms conditions not present, fossils destroyed or undiscovered
68
comparative anatomy?
fossil record incomplete so scientists look ar other sources of evid. It's the study of similarieties and diffrences n the anatomy of diff living things
69
what are homologous structures?
a structure that appears superficially diff (and may perform diff functions) in diff organisms, but has the same underlying structure e.g. pentadactyl limbs of vertabrates
- provides evid for divergent evol
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what is comparitive biochemistry?
- the study of similarities and diffs in the proteins and other molecules that control life processes.
- altho these mols change over time, some important ones are highly coserved among species. Slight changes can help identify evol. links
- 2 of the most common mols studied are rRNA & cytochrome
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what does the hypothesis of neutral evol state?
most of the variability on the structure of a molecule does not affect its function (because it occurs outside the mols functional region)
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what are changes that don't affect a molecules function are called?
neutral, their accumulation is not affected by NS
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How to discover how closely related 2 species are?
- the molecular sequence of a particular molecule is compared (done by looking at order of DNA bases or order of AAs in a protein
- The no. of diffs that exist are plotted against the rate
the mol undergoes neutral base pair substitutions
- from this, scientists can estimate the point at which 2 species last shared a common ancestor
- species that are closely related have more similar DNA & proteins
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why is rRNA commonly used w fossil info?
- rRNA has a very slow rate of sub so it is commonly used together w fossil info to determine relationships between ancient species
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What is classification?
the name given to the process by which living species are sorted into groups. the organisms within each group share similar features
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why do scientists classify organisms?
- to identify a species - by using a clearly defined system of class, the species an organism belongs to can be easily identified
- to predict characteristics - if several member in a group have spec characs, it's likely that another species in the group will have the same characteristics
- to find evolutionary links - species in the same group probs share characteristics bc they have evolved from a common ancestor
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what is the benefit of using a single classification system?
scientists worldwide can share their research. Links between different organisms can be seen even if they live on diff continent. Remember that CSs have been created to order obsereved characteristics organisms, this form of hierarchical organisation is not defined by nature.
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plural of genus?
genera
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before CSs were used, many organisms were given names according to physical charateristics?
This was not a very useful system for scientists working internationally, as organisms may have more than one common name, and different names in different languages. Another problem is that common names do not provide information about relationships between organisms
80
Unlike ppl?
No 2 species have the same spec and generic name. 2 diff species could have the same specific name but their genus would be diff.
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originally, organisms were classified into just kingdoms but
As more was discovered about organisms and more species were discovered, it became increasingly difficult to divide living organisms into just two kingdoms. For example, the introduction of the microscope in the 16th to 17th century enabled scientists to study the cells of an organism and showed that bacteria have a very different cell structure to that of other organisms. From the 1960s, scientists classified organisms into five kingdoms. This classification system was introduced by Robert Whittaker, an American plant ecologist, based on the principles developed by Carl Linnaeus
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Prokaryotae
| General features:
• unicellular
• no nucleus or other membrane-hound organelles - a ring of 'naked' DNA - small ribosomes
• no visible feeding mechanism - nutrients are absorbed through the cell wall or produced internally by photosynthesis
Examples include the bacteria Escherichia coli. Staphylococcus aureus, and Bacillus anthracis.
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Protoctista
| General features:
Examples include species belonging to the
genera Paramecium and Amoeba.
• (mainly) unicellular
• a nucleus and other membrane-bound organelles
• some have chloroplasts
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Protoctista
| General features:
Examples include species belonging to the
genera Paramecium and Amoeba.
• (mainly) unicellular
• a nucleus and other membrane-bound organelles
• some have chloroplasts
• some are sessile, but others move by cilia, flagella, or by amoeboid mechanisms
• nutrients are acquired by photosynthesis (autotrophic feeders),
ingestion of other organisms (hetcrotrophie feeders), or both -some are parasitic.
85
Fungi
| General features:
• unicellular or multicellular
• a nucleus and other membrane-bound organelles and a cell wall
mainly composed of chitin
• no chloroplasts or chlorophyll
• no mechanisms for locomotion
• most have a body or mycelium made of threads or hyphae
• nutrients are acquired by absorption - mainly from decaying
material - they are saprophytic feeders - some are parasitic
• most store their food as glycogen.
86
Plantae General features:
- With over 250000 species,
the plant kingdom is the second largest of the kingdoms
• multicellular
• a nucleus and other membrane-bound organelles including chloroplasts, and a cell wall mainly composed of cellulose
• all contain chlorophyll
• most do not move, although gametes of some plants move using cilia or flagella
• nutrients are acquired by photosynthesis - they are autotrophic feeders - organisms that make their own food
• store food as starch.
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Plantae General features:
- With over 250000 species,
the plant kingdom is the second largest of the kingdoms
• multicellular
• a nucleus and other membrane-bound organelles including chloroplasts, and a cell wall mainly composed of cellulose
• all contain chlorophyll
• most do not move, although gametes of some plants move using cilia or flagella
• nutrients are acquired by photosynthesis - they are autotrophic feeders - organisms that make their own food
• store food as starch.
Examples include flowering plants such as roses, trees such as oak, and grasses
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Animalia GF:
- The animal kingdom is the largest kingdom with over 1 million
known species.
• multicellular
• a nucleus and other membrane-bound organelles (no cell walls)
• no chloroplasts
• move with the aid of cilia, flagella, or contractile proteins, sometimes in the form of muscular organs
- Examples include mammals such as cats, reptiles such as lizards, birds, insects, molluscs, worms, sponges, and anemones.
• nutrients are acquired by ingestion - they are heterotrophic feeders
• food stored as glycogen.
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the organisms in the 3 domains?
contain a unique form of rRNA and diff ribosomes
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how are the domains split?
- bacteria goes into eubacteria
- archae go into archae bacteria
- eukarya goes into protoctista, plantae, fungi, animalia
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Archaebacteria?
Archaebaaeria, also known as ancient bacteria, can live in extreme environments. These include hot thermal vents, anaerobic conditions, and highly acidic environments. For example, methanogens live in anaerobic environments such as sewage treatment plants and make methane.
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Eubacteria?
Eubacteria, also known as true bacteria, are found in all environments and are the ones you will be most familiar with. Most bacteria are of the Eubacteria kingdom.
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Advantages of phylogenetic classification? (classification)
+ Phylogeny can be clone without reference to Linnaean classification. Classification uses knowledge of phylogcny in order to confirm the classification groups are correct or causes them to be changed. For example, a dolphin has many of the same characteristics as a fish, so in theory a dolphin could be classified as a fish. However, knowledge of the phylogeny of dolphins confirms its classification as a mammal
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other +s of phylogenetic classification?
* Phylogeny produces a continuous tree whereas classification requires discrete taxonomical groups. Scientists are not forced to put organisms into a specific group that they do not quite fit.
* The hierarchal nature of Linnaean classification can be misleading as it implies different groups within the same rank are equivalent
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Evidence for evolution?
* palaeontology - the study of fossils and the fossil record
* comparative anatomy - the study of similarities and differences between organisms' anatomy
* comparative biochemistry - similarities and differences between the chemical makeup of organisms.
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divergent evoluion?
The presence of homologous structures provides evidence for divergent evolution. This describes how, from a common ancestor, different species have evolved, each with a different set of adaptive features. This type of evolution will occur when closely related species diversify to adapt to new habitats as a result of migration or loss of habitat.
97
what is comparative biochemistry?
Comparative biochemistry is the study of similarities and differences in the proteins and other molecules that control life processes. Although these molecules can change over time, some important molecules are highly conserve«! (remain almost unchanged) among species. Slight changes that occur in these molecules can help identify evolutionary links. Two of the most common molecules studied are cytochrome c, a protein involved in respiration, and ribosomal RNA.
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the differences in characteristics between organisms are called?
variations
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The widest type of variation is between ?
members of different species - these differences are known as interspecifc variation.
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Causes of variation?
Two factors cause variation:
• An organism’s genetic material - differences in the genetic material an organism inherits from its parents leads to genetic variation.
• The environment in which the organism lives - this causes environmental variation.
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Genetic causes of variation?
Genetic variation is due to the genes (and alleles) an individual possesses:
1. Alleles (variants)
2. mutations
3. meiosis
4. sexual reproduction
5. chance
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alleles?
genes have different alleles (alternative forms). With a gene for a particular characteristic, different alleles produce different effects.
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mutations?
- changes to the DNA sequence and therefore to genes can lead to changes in the proteins that are coded for. These protein changes can affect physical and metabolic characteristics. II a mutation occurs in somatic (body) cells, just the individual is affected. However, il a mutation occurs in the gametes it may be passed on to the organism's offspring. Both can result in variation.
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meiosis ?
- gametes (sex cells - ovum ans sperm) are produced by the process of meiosis in organisms that reproduce sexually. each gamete receives half the genetic content of a parent cell. Before the nucleus divides and chromatids of a chromosome separate, the genetic material inherited from the two parents is mixed up' by independent assortment and crossing over. This leads to the gametes of an individual showing variation.
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sexual reproduction ?
- the offspring produced from two individuals inherits genes (alleles) from each of the parents. Each individual produced therefore diflers from the parents
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chance?
- many different gametes are produced from the parental genome.
- During sexual reproduction it is a result of chance as to which two combine (often referred to as random fertilisation).
- The individuals produced therefore also differ from their siblings
as each contains a unique combination of genetic material.
107
e.g. of characteristic that is determined purely by genetic variation
An example of a characteristic that is determined purely by genetic variation is your blood group.
The genes passed onto you from your parents determine il your blood group will be type A. B,
AB or O.
108
e.g. of characteristic that is determined purely by genetic variation
An example of a characteristic that is determined purely by genetic variation is your blood group.
The genes passed onto you from your parents determine il your blood group will be type A. B,
AB or O.
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Sperman rank correlation rule?
Where identical values exist, the 'average rank' should he used. So, if two equal values appear at rank 5, both are assigned the rank 5.5 (between ranks 5 and 6).
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what do r(s) values show?
An rs value of +1 shows a perfect positive correlation. An rs value of -1 shows a perfect negative correlation. An rs value of 0 shows no correlation.
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What are adaptations?
Adaptations are characteristics that increase an organism's chance of survival and reproduction in its environment.
Many adaptations fall into more than one category.
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Anatomical adaptations e.g.s?
·Body covering e.g. feathers - help to fly
·Camouflage - the outer colour of an animal allows it to blend into its environment, making it harder for predators to spot it.
- Teeth - the shape and type of teeth present in an animal's jaw arc related to its diet.
- Mimicry - copying another animal's appearance or sounds allows a harmless organism to fool predators into thinking it is poisonous or dangerous
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Behavioural adaptations e.g.s?
- Survival behaviours - e.g. rabbit freezes when they think they have been seen.
· Courtship - to attract a mate.
- Seasonal behaviours - these adaptations enable organisms to cope with changes in their environment: migration, hibernation
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Generally, behavioural adaptations fall into two main categories:
- Innate (or instinctive) behaviour - the ability to do this is inherited through genes.
- Learned behaviour - these adaptations are learnt from experience or from observing other animals.
but many behavioural adaptations are a combination of both
innate and learned behaviours
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Physiological adaptations e.gs?
- Poison production
- Antibiotic production
- Water holding
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Anatomical adaptations provide evidence for ?
convergent evolution
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what are selection pressures?
factors that affect the organism's chances of survival or reproductive success
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NS steps?
1. Organisms within a species show variation genetic variation.
2. Organisms whose characteristics are best adapted to a selection pressure such as predation, competition (for mates and resources) or disease, have an increased chance of surviving and successfully reproducing. Less well-adapted organisms die or fail to reproduce. This process is known as 'survival of the fittest'.
3. Successful organisms pass the allele encoding the advantageous characteristic onto their offspring.
4. Over time, the proportion of individuals with the advantageous adaptation increases.
5. Over very long periods of time, many, many generations and often involving multiple genes, this process can lead to the evolution of a new species.
119
Pre-adaptation is when?
an organism's existing trait is advantageous for a new situation
