Classification Flashcards
What is classification?
The process by which living things are sorted into groups. The organisms within the group share similar features
What is taxonomy?
The study of the principles behind classification
What is phylogeny?
The study of how closely related species are, looking at evolutionary relationships
Why do scientists classify organisms?
- to identify species
- to predict characteristics
- to find evolutionary links
What are the types of Linnaean classification?
- kingdom
- phylum
- class
- order
- family
- genus
- species
what is a species?
A group of organisms that are able to reproduce to produce fertile offspring
What does viable mean
the organism produced survives but it is not capable of producing offspring
Why are the offspring of different species infertile?
Because their cells contain an off number of chromosomes
When does having an odd number of chromosomes become a problem?
During meiosis as all chromosomes have to pair up
What are the 2 parts of the names all species are given?
- first word is the organisms genus (generic name)
- second word is the organisms species (specific name)
How do you write a species binomial nomenclature?
- genus always starts with a capital letter and species starts with a small letter
- if typed them it should be in italics
- is handwritten it should always be underlined
Explain what is meant by a hierarchical classification?
Grouping things based on similarities
Describe one way in which different species may be distinguished
different species can’t reproduce fertile offspring
Suggest some sources of evidence which scientists may have used to classify cheetahs and leopards into different species?
- common ancestors
- fossil evidence
- genomes/DNA
- characteristics
What has been the evolution of the five kingdoms?
- it used to be only two kingdoms, animal and plant
- as tech improves so did scientific knowledge
- this allowed what had been the plant kingdom to be separated out
What are the five kingdoms?
- protists
- monerans
- animals
- fungi
- plant
What are the types of ways animals feed?
- autotrophic
- heterotrophic
- saprotrophic
What is autotrophic feeding?
organisms that synthesise complex organic molecules from inorganic molecules via photosynthesis
What is heterotrophic feeding?
organisms that acquire nutrients by the ingestion of other organisms
What is saprotrophic feeding?
organisms that acquire nutrients through absorption- mainly decaying material
What type of cell is monera?
prokaryotic
What is the cell walls of monera made out of?
Peptidoglycan/ murien
Are monera uni or multicellular?
Unicellular
What is the method of feeding for monera?
Autotrophic
What are some examples of monera?
- salmonella
- E. coli
What type of cell are protocista?
Eukaryotic
what was early evolution based on?
observable characteristics and similarities in behaviour
what is used in classification now?
- DNA
- physiology and morphology
- biochemisty
how is DNA used to classify?
- the percentage of similar DNA shows how close the evolutionary relationship is
- the higher the percentage the more closely related in evolution the organisms are and the lower the percentage the less closely related they are
how is biochemisty used to classify?
the more similar the protein amino acid sequence, the more closely related the organisms are in evolution and vice versa
what did Carl Woese base his suggested classification system on?
- rNNA nucleotide sequences in eukaryotes and prokaryotes
- lipid structure and antibody sensitivity
what did Carl Woese decide about classification?
that prokaryotes had two distinct groups based on molecular structure and metabolic pathways
what is the domain summary in eukaryotes?
- 80s ribosomes
- RNA polymerase has 12 proteins
what is the domain summary in archaea?
- 70s ribosomes
- RNA polymerase has 8-10 proteins
what is the domain summary in bacteria?
- 70s ribosomes
- RNA polymerase has 5 proteins
what is phylogeny?
the evolutionary history of a species
what does a phylogenic tree show?
how traits diverge
what does it mean when 2 organisms are in a phylogenic tree?
the more probable they are closely related by evolution
what are the three domains?
- bacteria
- archaea
- eukaryotes
what are the five kingdoms?
- animal
- plant
- protists
- monera
- fungi
what is the eukaryotic organisation of domains?
1 - eukaryotes
what is the eukaryotic organisation of kingdoms?
4 - animal, protists, plant, fungi
what is the prokaryotic organisation of domains?
2 - bacteria and archaea
what is the prokaryotic organisation of kingdoms?
1 - monera
what is the process of natural selection?
1) genetic variation exists between individuals in a population (caused by mutation)
2) individuals with alleles that allow them to cope best with selection pressures survive and breed (survival of the fittest)
3) alleles encoding advantageous characteristics are more likely to be passed on to the next generation
4) over many generations, the frequency of the advantageous alleles increases within the population. This can lead to evolution of a new species
What is evolution?
Theory that describes the way that organisms evolve/change over many years as a result of natural selection
What is natural selection?
the process by which organisms best suited to their environment survive and reproduce, passing in their characteristics to their offspring through genes
What did darwin propose?
theory of natural selection
What did Lyell suggest?
suggested fossils were evidence of animals from millions of years ago and the principle of uniformitarianism
Why was Darwin’s theory very controversial?
It was against creationism and suggested that man descended form apes
What did Darwin observe?
- offspring generally appear similar to their parents
- no two individuals are identical
- large unsustainable numbers of offspring are produced
- populations in nature stay relatively stable
What did Darwin deduce?
- Characteristics are passed into the next generation
- there is a struggle of existence
- individuals with beneficial characteristics are among the few who survive
What are some factors that affect an organisms chance of survival?
- new predator
- competition
- food source
- change in physical environment
What does survival of the fittest mean?
that only those with the advantageous characteristic survive and pass on their alleles to their offspring
What are arguments against the theory of evolution?
- gaps in the fossil record
- surely natural selection would eliminate all exaggerated characteristics, but this can be explained by sexual selection
- went against creationism
- didn’t think the earth was old enough
What are protocista’s cell wall made out of?
cellulose if present
Are protocista unicellular or multicellular?
both
What is the method of feeding for protocista?
heterotrophically and autotrophically
What are some examples of protocista?
- seaweed
- algae
- amoeba
What type of cell is fungi?
eukaryotic
What is fungi’s cell wall made out of?
chitin
Are fungi unicellular or multicellular?
both
How do fungi feed?
saphrotrophically
What are some examples of fungi?
- yeast
- mushrooms
What type of cell are plant?
eukaryotic
What are plants cell wall made out of?
cellulose
Are plants multicellular or unicellular?
multicellular
How do plants feed?
phototrophically
What is an example of plants?
daffodil
What type of cell are animal cells?
eukaryotic
Do animal cells have a cell wall?
no
Are animal cells unicellular or multicellular?
multicellular
What are animals method of feeding?
heterotrophic
What are some examples of animals?
- tiger
- leopard
How are fossils produced?
when animal and plant remains are present in rocks
What is the fossil record?
a sequence of fossils from oldest to youngest which shows that organisms have gradually changed overtime
How old are the oldest Cyanobacteria fossils?
3.5 billion years
What is the proof that life forms evolved over an extremely long period of time?
fossils of the simplest organisms found in the oldest rocks, whilst fossils of more complex organisms are found in more recent rocks
How can fossils prove there are ecological links between species?
the sequence in which the organisms are found matches their ecological links to each other
How can scientists use fossils to show how closely related organisms have evolved from the same ancestors?
by studying similarities in the anatomy of fossil organisms, scientists can show how closely related organisms have evolved from the same ancestors
Are the oldest fossils on the lowest or highest rock layers?
lowest
Why is the fossil record incomplete?
- many organisms are soft bodied and decompose quickly before they can fossilise
- many have been destroyed
What is comparative anatomy?
the study of similarities and differences in the anatomy of different living species
What is homologous structure?
a structure that appears superficially different in the anatomy of different living species
why would you expect the limbs in vertebrae to be different?
they are used for a very wide variety of functions such as running so the bone structure would be different for different functions
what is thought to be the explanation behind the common bone structure in vertebrates?
all vertebrates have evolved from a common ancestors, therefore vertebrae limbs have all evolved from the same structure
how are Darwin’s finches an example of divergent evolution?
their beaks are different shapes but they have the same underlying structure
what is divergent evolution?
this describes how, from a common ancestor, different species have evolved, each with a different set of adaptive features
when might divergent evolution occur?
when a closely related species diversify to adapt to new habitats as a result of migration or loss of habitats
how do homologous features provide evidence for divergent evolution?
shows superficial structures that are different
what is comparative biochemistry?
the study of similarities and differences in the proteins and other molecules that control life processes
what are the important molecules that are highly conserved within most species?
- cytochrome c (protein involved in respiration)
- rRNA
what is neutral evolution in terms of biochemistry?
states that most of the variability in the structure of a molecule does not affect its function
where does the variability occur to allow it to be neutral and why is it not affected by natural selection?
- outside of the molecules functional regions
- due to the fact that they have no effect on function, their accumulation is not affected by natural selection
what is the evidence that chimps are a humans closest relative?
they have very similar DNA sequences, they have been found to share at least 98% of their DNA
how do scientists discover how closely related two species are?
the molecular sequence of a particular molecule is compared
why is rRNA commonly used to determine relationships between common species?
it has a very slow rate of substitution
species that are more closely related have…….?
more similar DNA and proteins
what is the definition of variation?
the differences between individuals within or between species
what is intraspecific variation?
variation between species
what is interspecific variation?
variation between species
what are some causes of variation?
- genetics
- environment
what is sexual reproduction?
individuals produced differ from their parents. this is because they inherit different alleles from each parent
what are mutations?
changes to the DNA base sequence that can cause changes to the tertiary structure of a protein
what is independent assortment?
homologous chromosomes line up randomly on the equator of the cell during metaphase i. this is then repeated when chromatids line up randomly on the equator in metaphase ii
what are alleles?
different versions of the same gene
what is crossing over?
non sister chromatids will form chiasmata during prophase i of meiosis
see IRL flashy for equation of standard deviation
what is a T test?
a statistical test that can be used to compare the mean of 2 populations
how do you do standard deviation?
1) find mean of figures (Xbar)
2) subtract Xbar from each figure (x)
3) square each figure
why do we do T tests?
to see if there is a significant difference between the 2 values
what must there be to conduct a T test?
- a big enough sample size
- data should be normally distributed
how do you right a null hypothesis?
there is no significant difference between the mean of ________ and the mean of _________.
see IRL flashy for the equation of T test
how would you write a conclusion for a T test?
as the t value of ________ (value) is higher/lower than the critical value of _________ at the 0.05 probability, then we reject/accept the null hypothesis between the means of population 1 and 2.
when would you accept the null hypothesis?
if your value is lower than the critical value
what is needed to do spearman’s rank?
2 sets of data from 2 paired variables
data does not have to be in a ________ distribution in spearman’s rank?
normal
how can data in spearman’s rank indicate correlation?
+1=perfect positive correlation
-1=perfect negative correlation
0=no correlation
how would you write a null hypothesis for spearman’s rank?
there is no statistically significant correlation between _______ and ________
see IRL flashy for equation for spearman’s rank
in spearman’s rank, if the Rs value is lower than the critical value, why would you accept the hypothesis?
as there is not a statistically significant correlation
how would you wite a conclusion for spearman’s rank?
as the Rs value of __ is higher/lower than the critical value of ___ at 0.05 probability, then we reject/accept the null hypothesis as there is/is not a statistically significant corrrelation between _______ and _______.
if the critical value and Rs value in spearman’s rank are the same, do you accept or reject the null hypothesis?
reject
