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The boring bit of Biology


Classification, evolution and biodiversity
Ben Levett
Flashcards by Ben Levett, updated more than 1 year ago
Ben Levett
Created by Ben Levett over 6 years ago

Resource summary

Question Answer
Define taxonomy The classification of organisms
List the 7 taxonomic groups Domain Kingdom Phylum Class Order Family Genus Species
Why do scientists classify organisms? So new species can be identified by referring to a clearly defined system To predict characteristics- species in the same group are likely to have similar features which may not be known about To find evolutionary links- species in the same group probably share characteristics because they have evolved from a common ancestor
Why do scientists use a single unified classification system So that they can share their research worldwide easily
List the 3 domains of organsims Archaea Bacteria Eukarya
Define species A group of organisms that are able to reproduce to produce fertile offspring
State the etiquette for writing the scientific name of an organism Italics (or underlined if handwritten) Uppercase first letter of genus name, then all lowercase
List the 3 components of scientific names of organsisms First word = genus (generic name, shared by closely related organisms) Second word = species (specific name to that species)
List the 5 kingdoms of living organisms Prokaryote Protoctista Fungi Plantae Animalia
State the general features of prokaryotae Unicellular, no nucleus or other membrane-bound organelles, ring of naked DNA, small ribosomes
State the general features of protoctista Unicellular (mainly), nucleus & other membrane-bound organelles, some have chloroplasts, nutrients acquired by photosynthesis (autorophic feeders) or ingestion of other organisms (heterotrophic feeders), some are sessile but others move by cilia, flagella or amoeboid mechanisms
State the general features of fungi Unicellular or multicellular, nucleus & other membrane-bound organelles, no chloroplasts or chlorophyll, no mechanisms for locomotion, body made of mycelium made of threads or hyphae, nutrients acquired by absorption- mainly from decaying material (saprophytic feeders), store food as glycogen
State the general features of plantae Multicellular, nucleus & other membrane-bound organelles including chloroplasts and a cellulose cell wall, all contain chlorophyll, most do not move, autotrophic feeders, store food as starch
State the general features of animalia Multicellular, nucleus & other membrane-bound organelles, no chloroplasts, move with cilia flagella or contractile proteins, heterotrophic feeders, food stored as glycogen/
Why have there been changes to classification systems over the years? As technology has developed it has become possible to study and compare the genetic sequencing of organisms to more accurately determine which animals have common ancestors
State the features of eukarya (3 domain system) 80s ribosomes RNA polymerase contains 12 proteins
State the features of archae (3 domain system) 70s ribosomes RNA polymeraase contains between 8 & 10 proteins Live in extreme environments
State the features of bacteria/eubacteria (3 domain system) 70s ribosomes RNA polymerase contains 5 proteins Most bacteria fall under this category
Define phylogeny Evolutionary relationships between organisms
What is a phylogenetic tree? A diagram used to represent the evolutionary relationship between organisms. The earliest species is at the base of the tree, and most recent at the tips of the branches
What information are phylogenetic trees created from Similarities and differences in species' physical characteristics and genetic makeup (often from fossils)
List the advantages of phylogenetic classification Phylogeny produces a continuous tree whereas classification uses discrete taxonomical groups which an organism might not quite fit into Can be done without reference to Linnaean classification Does not imply each groups have the same time period of existence, unlike Linnaean classification
How did Darwin develop his theory of evolution? He noticed that different finches on two different islands were very similar, apart from their beak and claws- which were evolved for the foods available on each island. Characteristics, offspring etc etc
Describe how palaeontology is evidence for evolution Fossils of the simplest organisms are found in the oldest rocks, and most more complex in younger rocks, showing that organisms got more advanced gradually. The order in which organisms are found matches their ecological links to each other (plants appear before animals) By studying the similarities in anatomy of fossil organisms, scientists can show how closely related organisms have evolved from the same ancestor Fossils allow relationships between extinct and living organisms to be investigated
Describe how comparative anatomy is evidence for evolution Homolygous structures appear in organisms (structures that appear superficially different and may perform different functions in different organisms, but with the same underlying structure) which provides evidence for divergent evolution- organisms have evolved from a common ancestor with a different set of adaptive features
Describe how comparative biochemistry is evidence for evolution Some important biological molecules stay mostly unchanged among species through evolution. Slight changes can help identify evolutionary links. The two most commonly studied molecules are cytochrome c (protein involved in respiration) and a ribosomal RNA By comparing differences in structure of these molecules in different organisms, scientists can determine the point at which the two species last shared a common ancestor.
Define interspecific variation Variation between members of different species (e.g mice have 4 legs and fur whereas birds have 2 legs and feathers)
Define intraspecific variation Differences between member of the same species (e.g. people vary in height, hair colour and intelligence)
List genetic causes of variation Allele variants Mutations Meiosis (independent assortment and crossing over) Sexual reproduction
Define discontinuous variation A characteristic that can only result in certain values e.g. sex, blood group, etc.
Define continuous variation A characteristic that can take any value within a range e.g. height, mass, etc. (often influenced by environmental variation
Define species richness The number of different species living in a particular area
Define species evenness The number of individuals of each species living in a community
Define habitat biodiversity The number of different habitats found within an area
Define genetic biodiversity the variety of genes that make up a species
Define random sampling Selecting individuals by chance- each individual in the population has an equal likelihood of selection
Define non-random sampling (3 techniques) A sampling method where the sample is not chose at random: Opportunistic- uses organisms that are conveniently available Stratified- populations are divided into strata (subgroups) based on a particular characteristic Systematic- different areas within a habitat are identified and then sampled separately (often carried out with a line or belt transect)
State why samples may be unreliable, and how that can be countered (2 reasons) Sampling bias- the selection process may be accidentally or deliberately biased (this can be reduced by using random sampling) Chance- organisms randomly selected may not be representative of the whole population (minimized by using a large sample size)
List & describe methods of sampling animals Pooter- mouthpiece sucking thing Sweep nets- catch insects in grass Pitfall traps- small insects fall into a hole and cant get out (sheltered from rain) Tree beating- hit a tree, insects fall onto a white sheet underneath the tree Kick sampling- river bank is kicked for a period of time and a net is held downstream to capture any organisms released from the disturbed bank
List & describe methods of sampling plants Point quadrat- frame with a horizontal bar. long pins pushed through bar at set intervals to reach the ground. Each species of plant the pin touches is recorded Frame quadrat- square frame divided into a grid of equal sections. The type and number of species within each section of the quadrat is recorded
List the sensors and measurement used for measuring wind speed, light intensity, relative humidity, pH, temperature and oxygen content in water Wind speed- anemometer, ms^-1 Light intensity- light meter, lx Humidity- humidity sensor, mgdm^-3 pH- pH probe, pH Temperature- temperature probe, °C Oxygen content in water- dissolved oxygen probe, mgdm^-3
State what each letter stands for in the equation for Simpson's index of biodiversity, and how to interpret the result D= Simpson's index of diversity- a measure of biodiversity N= total number of organisms fo all species n- total number of organisms of a particular species Answer will be between 0 & 1, 1 meaning infinite diversity and 0 meaning no diversity
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