Classification and Biodiversity Flashcards
- What does hierarchical mean in classification?
Organised into discrete smaller groups contained within a larger group
- What is the hierarchy of taxons from largest to smallest?
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
- What does phylogenetic mean?
Phylogenetic classification groups organisms based on their evolutionary relatedness
- Why is classification described as “tentative”?
The classification system is ever changing as scientific knowledge expands.
- What are the three domains?
Archaea
Eukaryota/eukarya
Eubacteria
- Which two of the domains contain prokaryotic cells?
Archaea and Eubacteria
- What feature of cells has been used to establish the relatedness of organisms into their domains?
Their ribosomal RNA in each domain share a distinctive and unique pattern
- What is an extremophile?
Organisms able to withstand extreme conditions e.g temperatures, pH’s, pressures
- Which of the 5 kingdoms have eukaryotic cells?
Animalia
Fungi
Plantae
Protoctisa
- What are the features of eukaryotes that distinguish them from prokaryotes?
Eukaryotes have membrane bound organelles and 80s ribosomes.
Prokaryotes do no not have membrane-bound organelles and have 70s ribosomes
- List distinguishing features of each of the 5 kingdoms.
Animalia:
- Nervous coordination
- Heterotrophic -> specifically Holozoic nutrition
- Lack cell walls
- Multicellular
Fungi:
- Heterotrophic -> Saprotrophic OR parasitic nutrition
- The cell wall is made of chitin
- Reproduce by spores or by budding
Plantae:
- Cell walls are made of cellulose
- Large central vacuole
- Autotrophic -> Photosynthesis
Protoctista:
- No tissue differentiation
- ALL have eukaryotic cells
- Can be Multicellular or unicellular
Prokaryotes:
- Prokaryotic cells (no membrane-bound organelles)
- Microscopic
- Circular DNA
- 70s Ribosomes
- Cell walls made of peptidoglycan
- Why are biochemical methods of assessing relatedness superior to using morphological features?
Morphological features can arise from convergent evolution, giving analogous features (same function but structurally dissimilar and from different origins). The same mutation occurred twice in separate ancestors that are not closely related due to the selective pressures of the environment.
- List 5 biochemical methods of establishing relatedness.
Immunological comparison:
- Antigens are injected from species A into species B to trigger antibodies.
- Blood sample taken from B with the antibodies and added to different blood samples from other species to see how well they recognise the proteins (Antigens) of other species.
- The more similar the species are to A, the more precipitate will form.
-
DNA hybridisation:
- Forming hybrid DNA: Isolate the DNA of two species and cut into fragments, and label one by attaching radioactive or fluorescent markers. Separate the initial double helix and mix together, hybrids will be 50% labelled.
- Separating: The amount of heating needed will determine how closely related they are.
- More heat = more hydrogen bonds = more complementary base pairings = more similar
- Less heat = Less hydrogen bonds = Less complementary base pairings = Less similar
DNA sequencing:
- Allows us to know the specific sequence of nucleotides.
- Align and then compare the similarities of the DNA sequences of organisms.
- Typically used to compare more closely related species because not all base changes will cause an amino acid change for them to be considered different enough to be another species.
Amino Acid Sequencing:
- Compares the amino acid sequence (primary structure) in a common protein between the tested organisms.
- Typically used to compare more distantly related species because not all base changes will cause an amino acid change for them to be considered different enough to be another species, so if there are many differences in amino acids this suggests a very different DNA sequence (more efficient than looking at every nucleotide if u already know the amino acids triplet codon is different).
DNA fingerprinting:
- Single-nucleotide polymorphisms (SNPs) are single-nucleotide differences in introns.
- Hyper-variable regions (HVR) are variable non-coding regions which are unique to the individual.
- Gel allows small fragments to move further, and the electrical charge causes the movement of the negatively charged fragments to the positive electrode.
- More similar banding patterns = more closely related
- Why are DNA base sequencing methods a better biochemical method than amino acid sequencing?
DNA base sequencing is more zoomed in as DNA is a degenerate code; not all base sequence changes will cause a change in amino acid. 64 Codons but only 20 amino acids.
- Define homologous and analogous and give an example of each.
Homologous: Features which arise from divergent evolution as they come from the same ancestor but are functionally different.
- Pentadactyl limb
Analogous: Features which arise from convergent evolution as they come from different ancestors but are functionally similar.
- Wings of a butterfly and a bat
- Define a species.
Organisms which can interbreed to produce fertile offspring.
- What does binomial naming mean?
- Universal naming system
- ‘Genus species’
- What taxons do the first and second names represent?
Genus
Species
- Where are the common ancestors located on a phylogenetic tree?
At branch points
- How could you use a phylogenetic tree to organise most closely to least closely related?
Species with more recent branching points/common ancestors are more closely related than those with distant common ancestors.
- Define biodiversity.
The number of species and the number of individuals within those species in a specified region.
- How does biodiversity vary between the two poles of the earth?
The poles are less biodiverse than the equator and tropics
- What does “biodiversity varies temporally” mean?
Biodiversity varies temporally – through time biodiversity has varied, e.g. mass extinctions reduce biodiversity.
- List the factors that can cause variation in biodiversity.
- Spatial/environmental variation: Bright environments = higher energy flow and greater biodiversity. High around the equator and tropics
Bright environment with higher light intensity, so more plants grow here than low light intensity region. More energy flowing through an ecosystem produces more species and more individuals, thus higher biodiversity. - Succession: The Community changes its habitat to be more suitable for its species, changing the community composition. Animal biodiversity typically increases while plant biodiversity decreases.
- Natural selection: Evolve to form new species whilst others don’t survive. Survival of the fittest
- Human factors: Pollution, deforestation, agriculture, and overfishing physically remove species or destroy their habitats. Farming has caused a monoculture to grow one crop to increase yield.
- What calculation is performed to assess biodiversity in a habitat?
Simpson’s biodiversity index = 1−∑n( n − 1 ) / N( N −1)
∑n( n − 1 ) is the sum of number of n(n-1) of each species.
N is the total number of organisms
- What are the two things that must be counted to do this calculation?
The number of species
The number of individuals of each species
- What two number form the lower and upper limits of the calculation?
Lower = 0
Upper = 1
- How could you tell from the calculation that an area was more diverse than another?
Index values between 0 to 1, closer to 1 = more biodiverse
- Describe how you would sample two areas to get representative data.
Random Quadrat or Transect sampling for plants
- Divide the two areas into 100 sections.
- Measure plant diversity by counting no. plants per m^2.
- Estimate mean % area cover
- OR length of rope and measure at intervals along an environmental gradient by placing quadrats and counting
Kick sampling and Simpson index for freshwater invertebrates:
- Collect and identify from the given areas using a quadrat and net.
- Kick or rake the two areas for a set period and collect downstream in the net.
- Replace carefully, find means using both areas and then calculate Simpson’s index.
(For population size)
Mark-release-recapture for terrestrial animals:
- Capture and mark dont make them more visible to predators or harmed and then release.
-Set traps 24 hrs later and catch individuals.
- Population size = (no. in sample 1 * no. in sample 2) / no. marked in sample 2
- What is polymorphism?
The occurrence of more than one phenotype in a population that cannot be accounted for by mutation alone. Polymorphic genes (multiple alleles)
- How could you recognise genetic polymorphism in a species?
Gel electrophoresis (DNA fingerprinting) is the most commonly used procedure to detect these polymorphisms
- How would you assess genetic diversity in a species?
All members of the same species have the same genes, but can have different alleles.
Variation in DNA base sequence.
Different genotypes = different phenotypes.
Greater number. different alleles in all members of a species = greater genetic diversity
- How can biodiversity be determined at a molecular level within a species?
DNA fingerprinting:
- Single-nucleotide polymorphisms (SNPs) are single-nucleotide differences in introns.
- Hyper-variable regions (HVR) are variable non-coding regions which are unique to the individual.
- Gel allows small fragments to move further, and the electrical charge causes the movement of the negatively charged fragments to the positive electrode.
- More differences in intron banding patterns = more variation/genetic diversity within species
- What feature would inform you that a species was genetically diverse?
Lots of differences in banding patterns
- How has biodiversity on the planet been generated?
Natural selection is the process in nature by which only the organisms best adapted to their environment tends to survive and transmit their genetic characters in increasing
numbers to succeeding generations, while those less adapted tend to be eliminated.
4 stages of natural selection:
- Mutation is the only process that produces new genetic material.
- As more and more mutations occur within a population, its gene pool will change.
- Variation exists between organisms.
- Competition for resources due to selection pressures.
- Best adapted have a selective advantage – outcompete others for resources.
- Reproduction of the best adapted.
- Pass on advantageous alleles to offspring.
- Give examples of organisms that are anatomically behaviourally and physiologically adapted to extreme environments like deserts and the arctic.
Anatomical:
- Sharks have streamlined bodies
- Some plants have flowers with honey or nectar guides called beelines to indicate the centre of the flower to attract pollinators.
Physiological:
- Hibernation: Mammals and birds are endothermic, so when it is cold, they have to try and avoid wasting energy to maintain body temperatures
- Deciduous trees lose their leaves when temperature and light intensity decrease in autumn to minimise water loss and risk of dehydration when water may be frozen
Behavioural traits:
- Some animals perform mating rituals to increase the chances of reproducing.
- Many plants flower in spring, when the pollinators have emerged, so they are pollinated. If they flower early or later, they do not get pollinated.
