4.3-classification and evoluion Flashcards
What is taxonomy ?
Classification using physical similarities between different species.
What is phylogeny?
Classification using evolutionary relationships, so that each group shares a common ancestor.
Why do we classify living things ?
- convenience
- to make the study of living things more manageable
- to make it easier to identify organisms
- to help us see the relationships between species
What are the 8 taxonomic levels ?
Domain Kingdom Phylum Class Order Family Genus Species
What are the 5 kingdoms ?
Plantae Animalia Fungi Protoctista Prokaryotae
What are the 3 domains ?
Archaea
Eubacteria
Eukaryotae
Why does using a common name not work well?
1) Same organism may have completely different common name in different parts of 1 country
2) different common names are used in different countries
3) translation of languages or dialects any give different names
4) same common name could be used for different species in other parts of the world
What is the binomial system of naming organisms ?
A system that uses the genus name and the species name to avoid confusion when naming organisms.
what are the features of prokaryotae ?
- no nucleus
- a loop of dna- no chromosomes
- naked dna- no histone proteins
- no membrane bound organelles
- smaller ribosomes
- smaller cells than eukaryotes
- may be free living or parasitic
What are the features of protoctista ?
- eukaryotic
- mostly single celled (exception=algae)
- show a wide variety of forms
- the only thing they have in common is that they don’t qualify to belong in any of the 4 kingdoms
What are the features of fungi ?
- eukaryotic
- can exist as single cells (yeasts) or they have a mycelium that consists of hyphae
- chitin walls
- multinucleate nucleus
- mostly saprophytic
What does saprophytic mean ?
Cause decay of organic matter
What are the features of plantae ?
- eukaryotic
- multicellular
- cellulose cell wall
- autotrophic
- contain chlorophyll
What does autotrophic mean ?
Absorb simple molecules and build them into larger organic molecules
What are the features of animalia ?
- eukaryotic
- multicellular
- heterotrophic
What does heterotrophic mean?
Digest large organic molecules to form smaller molecules for absorption
what is cytochrome c?
a protein used in the process of respiration
how can cytochrome c be used in classification?
if we compare the sequence of amino acids in cytochrome c from 2 different species, we can see how similar they are, so how closely related they are.
why is cytochrome c a good biological molecule to use in classification?
same between the same species
differs between different species.
what is the three domain classification?
dividing prokaryotae into 2 different domains-bacteria and archaea.
why are bacteria different from archaea?
bacteria have:
- 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
why are archaea similar to eukaryotes?
they have similar enzymes (rna polymerase) for synthesising rna.
they have similar mechanisms for dna replication and synthesising rna
they both have proteins bound to their dna.
what is artificial classification?
classifications done for convenience, eg have all the yellow flowers on one page, all blue flowers on the next page
what are the features of artificial classification?
- based on only a few characteristics
- doesn’t reflect any evolutionary relationships
- provides limited information
- stable
what is natural classification?
- uses many characteristics
- reflects evolutionary relationships
- provides a lot of useful information
- may change with advancing knowledge
why could natural classification be useful in conservation?
if you want to find out about an endangered species, you wouldn’t want to risk harming any of the few surviving members BUT if you know of a similar species hat’s not endangered you can carry out research on that instead that also applies to the endangered species.
what 4 observations did Darwin make?
1) offspring generally appear similar to their parents
2) no 2 individuals are identical
3) organisms have the ability to produce large numbers of offspring
4) populations in nature tend to remain fairly stable in size.
what were Darwin’s three 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 new species.
how does recent study of biological molecules provide evidence for evolution?
-the fact that certain molecules are found throughout the living world is evidence in itself-suggests that all species came from a foreign ancestor.
what is continuous variation?
variation where there are 2 extremes and a full range of values in between
what is discontinuous variation?
where there are distinct categories and nothing in between
how is it best to graph continuous variation?
histogram
how is it best to graph discontinuous variation?
bar chart
what is the correlation coefficient ?
measures how closely 2 sets of data are correlated- a value of 1 means perfect correlation, eg spearman
what is standard deviation?
a measure of spread around a mean
what is a student’s t test?
a test used to compare 2 means
what is a well adapted organism able to do?
- find enough food/photosynthesise
- find enough water
- gather enough nutrients
- defend itself from predators and disease
- survive physical conditions of its environment eg changes in temp, light, water availability
- respond to changes in its environment
- have sufficient energy for successful reproduction
what are the 3 kind of adaptation?
anatomical
behavioural
physiological
how does natural selection work?
1) mutation creates alterative versions of a gene (alleles)
2) this creates genetic variation between the individuals of a species-INTRASPECIFIC VARIATION
3) when resources are scarce, the environment will select those variations that give an advantage -there is a selection pressure.
4) individuals with advantageous characteristics will survive and reproduce
5) they will pass on their advantageous characteristics -inheritance
6) the next generation will have a higher proportion of individuals with the successful characteristics. over time, the group of organisms becomes well adapted to its environment (adaptation)
what is an example of an insecticide that insects have become resistant to?
DDT
