Classification and Evolution Flashcards
Define the term Classification
The act of arranging organisms into groups based on their similarities and differences
Define the term taxonomy
The study of classification
Define the term taxonomic group
The hierarchical groups of classification- domain, kingdom, phylum, class, order, family, genus, species
Define hierarchical
Arranged so that each entity is subordinate to a different entity.
Define phylogeny
The evolutionary relationships between organisms
List the seven taxonomic groups, in order, from the broadest to the smallest.
Domain, kingdom, phylum, class, order, family, genus, species
Name the taxonomic level that has been added above kingdom.
Domain
Give 3 reasons why scientists classify organisms.
- To identify species- by using defined system of classification, the species an organism belongs to can be easily identified.
- To predict characteristics- if several members in a group have a specific characteristic, it’s likely other species in the group will have the same characteristic
- To find evolutionary links- species in the same group probably share characteristics as they have evolved from a common ancestor
Define the term “species”.
The smallest and most specific taxanomic group. A species are a group of organisms that are able to reproduce and produce fertile offspring.
Explain why horses and donkeys are separate species, and why mules are not given a scientific name and are not a separate species.
When horses and donkeys breed they produce infertile offspring.
Mules are the offspring of a donkey and a horse. they are infertile because their cells contain an odd number of chromosomes. Because it’s infertile they are not classified as a species- so no scientific name
Define scientific name
The taxonomic name of an organism that consists of its genus and species
Define binomial nomenculture
The scientific naming of a species with a Latin name made of two parts- the first indicating the genus and the second the species
Define generic name
The first word in binomial nomenculture that indicates the an organism’s genus.
Define specific name
The second word in binomial nomenculture that indicates the organism’s species
Explain how scientific names of species are derived from the classification of a species and state the conventions used in writing them.
Write in italics or underline the name. It should be written in lower case except for the first letter of the genus name.
Name the 5 kingdoms and give examples of the organisms they contain.
- Prokaryotae (bacteria)
- Protoctista (the unicellular eukaryotes) Amoeba.
- Fungi (yeasts, moulds, mushroom)
- Plantae (the plants)
- Animalia (animals)
Describe the characteristics of Prokaryotae
- Unicellular
- No nucleus or other membrane bound organelles- a ring of naked DNA- small ribosomes
- No visible feeding mechanism- nutrients are absorbed through cell wall or produced internally by photosynthesis.
Describe the characteristics of Protocista
- Mainly unicellular
- A nucleus and other membrane-bound organelles
- Some have chloroplasts
- Some are sessile but others move by cilia or flagella or amoeboid mechanisms
- Nutrients are acquired by photosynthesis (autotrophic feeders), ingestion of other organisms (heterotrophic feeders) or both, some are parasitic
Describe the characteristics of Fungi
- Unicellular, 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 decaying material- they are saprophytic feeders- some are parasitic.
- Most store their food as glycogen
Describe the characteristics of Plantae
- 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
Describe the characteristics of Animalia
- 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
- Nutrients are acquired by ingestion- they are heterotrophic feeders
- Food stored as glycogen
State the 3 domains of life and the 6 kingdoms in the ‘Three Domain system’- Woese’s system
- Domains- Bacteria, Archaea and eukarya
2. Kingdoms- Eubacteria, archae-bacteria, protoctista, plantae, fungi, animalia
Describe the characteristic features of Bacteria
- Have 70s ribosomes
2. RNA polymerase contains 5 proteins
Describe the characteristic features of Archaea
- Have 70s ribosomes
2. RNA polymerase of different organisms contain between eight and 10 proteins.
Describe the characteristic features of Eukarya
- Have 80s ribosomes
2. RNA polymerase contains 12 proteins
Describe the evidence used to create the “Three Domain System” of classification.
Scientists can discover evolutionary relationships between organisms by comparing DNA and protein structure.
These observations are used to classify organisms.
Define phylogeny
The study of living organisms based on their evolutionary relationships
Define phylogenetic tree
It is a diagram used to represent evolutionary relationships between organisms.
Shows common ancestors
Define the term sister group
Two descendants that split form the same node are called sister groups
Define node
The points where new lines branch off
Define tip
Tips on phylogenetic trees represent groups of descendant organisms.
Describe the advantages of using phylogenetic trees as a form of classification as opposed to just using taxonomic groupings.
- Uses phylogeny to confirm classification groups or caused them to be changed.
- Produces continuous tree whereas classification requires discrete taxonomical groups- scientists aren’t forced to put organisms into a specific group that they don’t quite fit.
- The hierarchical classification can be misleading as it implies different groups within the same rank are equivalent.
State 3 different sources of evidence for evolution
- Palaeontology- study of fossils and the fossil record
- Comparative anatomy- the study of similarities and differences between organism’s anatomy
- Comparative biochemistry- similarities and differences between the chemical makeup of organisms
Explain how the fossil record provides evidence for evolution.
- Fossils of simpler organisms are found in the oldest rocks, whilst fossils or more complex organisms are found in more recent rocks.
- Sequence in which organisms are found matches their ecological links with each other-plant fossils found before animal fossils.
- Study similarities in anatomy of fossil organisms- shows how closely related organisms have evolved from the same ancestor
Explain how the (relative) age of fossils can be determined.
- Sediment is deposited on the earth to form layers of rock.
- Different layers correspond to different geological eras.
- Within the different rock layers the fossils found are quite different - forms sequence form oldest to youngest- shows how organisms have gradually changed.
Explain how comparative anatomy provides evidence for evolution.
- The presence of homologous structures provides evidence for divergent evolution.- describes how, from a common ancestor, different species have evolved.
Define divergent evolution
Species diverge over time into two different species, resulting on a new species becoming less like the original one
Define homologous structre
A homologous structure is a structure that appears superficially different in different organisms but has the same underlying structure.
Explain how comparative biochemistry provides evidence for evolution
- Gathering molecular evidence involves analysing the similarities in proteins and DNA.
- More closely related organisms will have more similar molecules.
- You can compare things like how DNA is stored and the sequence of DNA bases
- From this comparison, scientists cam identify the last point that two organisms last shared a common ancestors.
Summarise how Darwin and Wallace formulated the theory of evolution by natural selection.
He noticed that different islands had different finches- different beaks
- He realised the design of the beaks was linked to the food available.
- A bird born with a beak more suited to the food would survive longer and have more offspring, passing on its character.
Define the term variation
The differences in characteristics between organisms are called variation
Define interspecific variation
The differences between organisms of different species
Define intraspecific variations
The differences between organisms of the same species
Name and describe the two causes of 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.
Describe 5 causes of genetic variation between individuals within a population.
- Alleles- with a gene for a particular characteristic, different alleles produce different affects. Individuals in a species population may inherit different alleles of a gene.
- Mutations- Changes to the DNA sequence and therefore to genes can lead to changes in the proteins that are coded for.
- Meiosis- gametes are produced by meiosis. Each gamete receives half the genetic content of a parent cell. The genetic material is mixed up by independent assortment and crossing over.
- Sexual reproduction- offspring produced from tow individuals inherits genes form each of the parents
- Chance- different gametes are produced and in reproduction it is chance as to which two combine- individuals differ from siblings
State 3 characteristics which are solely genetically determined
- blood group
- eye colour
- shape of ear lobes
State 2 characteristics which are solely characteristically determined
- Scars
2. piercings
State 3 characteristics which are determined by a combination of environment and genetics
- Skin colour
- Height/weight
- hair colour
Define the term continuous variation
A characteristic that can take any value any value within a range e.g height
Define the term discontinuous variation
A characteristic that can only result in discrete values e.g. blood type
Describe the causes of variation that result in discontinuous variation.
Variation determined purely by genetic factors falls into the discontinuous category. Most characteristics are controlled by a single gene.
Describe the term polygenic
A characteristic that is controlled by a group of genes
Describe the term multifactorial
Characteristics which are dependent on a number of factors.
Describe the causes of variation that result in continuous variation.
Characteristics which show continuous variation are controlled by a number of genes and are also often influenced by environmental factors.
State the types of graph used to represent continuous and discontinuous variation within a population.
Continuous- frequency tables which are then plotted onto a histogram, a curve is then normally drawn to show a trend.
Discontinuous- bar chart, pie chart.
Describe histograms
X-axis - class width- write measuring thing- height etc. Y-axis - Frequency density= frequency/class width
Define the term “normal distribution curve” and give 4 characteristics of a normal distribution.
- Bell-shaped curve- with the peak at the mean
Characteristics: - Mean, median and mode are the same
- Curve is symmetrical around the mean
- 50% are below and 50% are above the mean
- Most values lie close to the mean
Define standard deviation
How spread out the data is. The greater the deviation the greater the spread of data
Describe the meaning of each of the symbols in the equation for calculating standard deviation.
Look it up and remember how to use graphical calculator
Explain why statistical tests are important and what they are used for.
Statistical tests can be used by scientists to determine the significance of data collected.
Define the terms “hypothesis” and “null hypothesis”.
Hypothesis- an idea or an explanation which then needs to be confirmed through experimentation
Null hypothesis- The idea that there is no significant difference between specified populations and so any observed difference would be due to chance variation in a sample
Define the critical value
Critical value- A critical value is the point (or points) on the scale of the test statistic beyond which we reject the null hypothesis
Define the test statistic
A test statistic is a standardized value that is calculated from sample data during a hypothesis test.
Define p-value
The probability that the null hypothesis is true
Describe when a students T-test would be used to analyse data
Used to compare the means of data values of two populations.
The data must be normally distributed and enough data must be collected to calculate a reliable mean.
Describe when a Spearmen’s rank correlation coefficient would be used to analyse data
Used to consider the relationship between two sets of data- to see if there is a correlation
Describe when a paired t-test would be used and when an unpaired t-test would be used to analyse data.
Paired- to analyse the difference between the means of two data-sets where the data from both data-sets was collected form the same subject.
Unpaired- where the data from both data-sets was collected from different subjects
Describe the meaning of each of the symbols in the equation for calculating the t-value (the test statistic) from an unpaired Student’s t-test.
Look it up
Describe the meaning of each of the symbols in the equation for calculating the correlation coefficient (test statistic) from a Spearman’s rank correlation.
Look it up
Define the term adaptation and state 3 types of sdaptaion
Adaptations are characteristics that increase an organism’s chance of survival and reproduction in the environment.
- Anatomical- physical features
- Behavioural- the ways an organism acts- inherited or learnt form parents
- Physiological- processes that take place inside an organism
Give 4 examples of anatomical adaptations
- Body covering- hair, scales feathers- help to fly, stay warm
- Camouflage- outer colour which allows an organisms to blend into its environment- make it harder for predators to spot.
- Teeth- shape and type are related to an animal’s diet.
- Mimicry- copying another animals appearance or sounds allow harmless animals to fool predators into thinking it’s poisonous or dangerous.
Give 3 examples of behavioural adaptations
- Survival behaviours- opossum plays dead and rabbits freeze when in danger
- Courtship- many display elaborate behaviour to attract a mate- increases chance of reproducing.
- Seasonal behaviours- migration and hibernation and allows animals to cope with changes in their environment.
Give 3 examples of physiological adaptations
- poison production- many reptiles produce venom to kill prey and plants to protect themselves form being eaten.
- Antibiotic production- some bacteria produce antibiotics to kill other species of bacteria in the surrounding area
- Water holing- store water in the body to allow it to survive in dry climates.
Define the term analogous structure
Structures that have adapted to form the same function but have a different genetic origin
Define the term convergent evolution
Organisms evolve similarities because the organisms adapt to similar environments or other selection pressures.
Draw a table to compare the features of the marsupial mole and the placental mole.
Marsupial mammals- start life in the uterus, but then leave and enter the marsupium (pouch ) while they are still embryos.- moles have white-orange to match soil colour
Placental mammals- Connects the embryo to it’s mother’s circulatory system in the uterus- reaches a high level of maturity before birth.- moles are grey to match soil
Define the term evolution
The change in allele frequency within a gene pool over time
Define the term natural selection
The process by which organisms best suited to their environment survive and reproduce, passing on their characteristics to their offspring through their genes
Define the term allele frequency
The relative frequency of a particular allele in a population in a given time
Define the term gene pool
Sum total of all the genes in a population at a given time
Define the term selection pressure
Factors that affect an organisms chance of survival or reproductive success
Define the term selectively neutral allele
A variety of a gene that doesn’t provide a selective advantage or disadvantage to the organism
Define advantageous allele
A variety of a gene that provides a selective advantage to the organism
Define advantageous characteristic
One form of a part of an organism’s phenotype that provides it with a selective advantage
Describe the steps in the process of adaptations evolving by natural selection.
- Organisms within a species show variation in their characteristics that are caused by genetic variation.
- Organisms whose characteristics are best adapted to a selection pressure- predation, competition- have an increased chance of surviving and successfully reproducing
- Successful organisms pass the allele encoding the advantageous characteristic onto their offspring.
- This process is repeated for every generation. Over time, the proportion of individuals with the advantageous adaptation increases. There fore the frequency of the allele that codes for this increases in the population’s gene pool.
- Over a very long periods of time this process can lead to the evolution of new species
Explain how natural selection has resulted in the change in frequency of dark and pale moths in populations of the peppered moth (Biston bettularia) near industrial towns and cities over time.
- In industrial revolution trees became darker and so the dark moths were better adapted, so more survived etc. frequency of the dark allele increased
- Now trees are lighter the frequency of the pale allele in the moth gene pool has increased
Describe how human activity has resulted in evolution in populations of the bacterium Staphylococcus aureus, the Sheep blowfly Lucilia cuprina, and the bacterium Flavobacterium.
- Sheep blowflies- laid eggs in sheep’s tails, pesticide was introduced and they became resistant to it
- Bacterium- a strain of bacteria which have evolved to digest nylon and live in waste water form factoids that produce nylon.
- Staphylococcus aureus- has developed resistance to many antibiotics. when exposed resistant individuals survived etc.
