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Flashcards in Classification and Evolution Deck (55):

name the modern classifying hierarchy

- domain
- kingdom
- phylum
- class
- order
- family
- genus
- species


name the three domains

- archaea
- eubacteria
- eukaryotae


what are the 5 kingdoms





a major subdivision of the kingdom, a phylum contains all the groups of organisms that have the same body plan



a group of organisms that all posses the same general traits



a subdivisdion of the class using additional information about the organisms



a group of closely related genera



a group of closely related species



the basic unit of classification


What's a binomial?

a system that uses the genus name and the species name to avoid confusion when naming organisms


binomial name of humans

Homo sapiens - take the genus name and species name


why do you have a binomial name?

- the same organism may have a completely different common name in different parts of one country
- different common names are used in different countries
- translation of languages or dialects may guve different names
- the same common name may be used for different species in other parts of the world
- Linnaeus used Latin this is where every scientist in every country will use in the same name


Describe prokaryotae

- have no nucleus
- have a loop of DNA that is not arranged in linear chromosomes
- Have naked DNA - not associated with histone proteins
- have no membrane-bound organelles
- have smaller ribosomes than in other groups
- have cells smaller than those of eukaryotes
- may be free-living or parasitic


describe Protoctista

- are eukaryotic (have a nucleus)
- mostly single celled but many algae are multicellular
- shows a wide variety of forms - only common thing is that they do not qualify to belong in other kingdoms
- show various plant like or animal like features
- mostly free living
- have autotrophic or heterotrophic nutrition - some photosynthesis some ingest prey and some feed using extracellular enzyme and some are parasites


Describe Fungi

- are eukaryotic
- can exist as single cells or they have a mycelium that consists of hyphae
- have walls made of chitin
- have a cytoplasm that is multinucleate
- are mostly free living and saprophytic - this means that they can cause decay of organic matter


Describe Plantae

- are eukaryotic
- multicellular
- have cells surrounded by a cellulose cell wall
- are autotrophic - absorb simple moleucles and build them into larger organic molecules
- contain chlorophyll


Describe Animalia

- are eukaryotic
- are multicellular
- heterotrophic - digests large organic molecules to form smaller molecules for absorption
- are usually able to move around


How did Linnaeus put living organisms into groups

- he based it on appearance and anatomy


How did Aristotle classify all living things

either plant or animal
then he classed them into
- live and move in water
- live and move on land
- move through air


what happened in the 17th century that suggested that not everything you observe can put them into the right group

- microscopes were created in the 17th century


what is an euglena

this is a single celled organism that has chloroplasts to photosynthesis, it also has the ability to move around using a flagellum one of the reasons that lead to the 5 kingdoms


Who suggested the 3 domain classification

in 1990 Carl Woese suggested a new classification system


What did Carl Woese base his domain idea on

a detailed study of the ribosomal RNA Gene


What was the 3 domains that Carl Woese came up with

Archaeae, Bacteria, Eukaryote (He divided the kingdom prokaryote into two groups)


What are the differences in bacteria

- a different cell membrane structure
- flagella with a different internal structure
- different enzymes( RNA polymerase for synthesising RNA)
- no proteins bound to their genetic material
- Different mechanisms for DNA replication and for synthesising RNA


When did the archaea share certain features with eukaryotes

- similar enzymes (RNA polymerase) for synthesising RNA
- Similar mechanisms for DNA replication and synthesising RNA
- production of some proteins that bind to their DNA


Why do Woese separate the bacteria and the Archaea

he argued that the differences between the archaea and the bacteria are fundamental
whereas the differences between archaea and eukaryote are different - therefore it must reflect the difference


Why did the classification system of two groups change into 3 groups

- euglena
- fungi - hypae that acted like roots as they grew into the surroundings but they were hetertrophic such unlike plants


What is convergent evolution

This is when two unrelated species could adapt in similar ways and therefore look similar for example a dolphin and shark, as they may have adapted in a similar niche


What do biological molecules help us do

They help us classify organism better than just using there observable features
- they help us identify how closely one species is to another


Why are only certain biological molecules used

only certain biological molecules are used as these are the biological molecules that around found in all organisms as they are fundamental for life
- for example cytochrome C is used in respiration therefore is in all organisms but it is not identical in all species


Explain how cytochrome c works

it is made form chains of amino acids, therefore when comparing how closely related two different organisms are we look at the chains on the amino acids
- if sequences are very similar/same then they are closely related, if the sequences are different then they are less closely related


Explain how DNA can be used to see how closely related an organism is?

DNA is found in all living things, this provides a genetic code with amino acid sequence
- mutations occur which distort the sequence of bases in DNA, these happen randomly
- the more closely related the species are the less mutations and bases that they will have different


What did Darwin come up with

natural selection


How did Darwin come up with his theory

this was developed on his time studying animals on his 5 year trip to the Galapagos islands, he realised that the same bird had different variations on different islands therefore he concluded that a species of bird must have migrated to different islands but then adapted to suit that island (environment better)


What are Darwin's 4 observations

1. offspring generally appear similar to their parents
2. no two individuals are identical
3. organisms have the ability to produce large numbers of offspring
4. populations in nature tend to remain fairly is size


What are Darwins 3 conclusions

1. there is a struggle to survive
2. better-adapted individuals survive and pass on their characteristics
3. over time a number of changes may give rise to a new species


What have fossils shown us

1. in the past the world was inhabited by species that were different to the ones present today
2. old species have died out and new species have arisn
3. the new species that have appeared are often similar to the older ones that our found in the same place


what did Darwin understand from fossils

He began to understand that the fossils gave rise to the modern species that we have today, the more modern species were better adapted to the environment and therefore survived whereas the fossils had died, many fossils were much larger than modern species we have today


why are fossils good

allow use to see a complete fossil record of evolution this shows us how one species has risen from another


what is the presences of differences between individuals called



are identical twins different or the same

different, start of as one cell but as that one cell divides more and more the cell divisions may have caused mutations and changes to the DNA therefore they are not the same
- environmental differences may also cause them to be different


what is intrAspecific variation

the variation between members of the same species


What is intErspecific variation

the variation between species


What is continuous variation

this is where there are two extremes and a full range of intermediate values between those two extremes
- most individuals are close to the mean value and the number of individuals at each end is low
- regulated by more than one gene and influenced by the environment in which the individual lives


Name so examples of continuous variation

- height in humans
- length of leaves on a oak tree
- length of stalk
- number of flagella on bacterium


What is discontinuous variation

this is where there are two or more distinct categories with no intermediate values, members of a species may be evenly distributed between the different forms or there may be one type more than thte other
- regulated by a single gene and not usally influenced by the environment around it


examples of discontinuous variation

- gender
- some bacteria have flagella but others do not
- human blood groups


What are the causes of variation

- environmental
- inherited


how do you know if its inherited or genetic

- inherited - define our characterstics, the combination of alleles we receive is individual to ourselves there can never be a complete match of genes and alleles even though we may share a lot of them


Environmental variation

- characterstics can be effected by the environment for example eating to much or getting a tan


Give some examples of combined effects of environmental and genetic variation

- in the past humans have become taller as the result of better diet, but height is limited by genes
- not all genes are active at any one time - for example some genes become active when you reach puberty
- changes in the environment can affect which genes are active


Draw the formula for the standard deviation



What does standard deviation measure

it is a measure of variation, it measures the amount of variation or spread from the mean


What is taxonomy

The system of classifying organisms according to their observable features or genetic characteristics