Biodiversity, Evolution and Disease Flashcards
10.1
What is taxonomy?
All organisms share a common ancestor, from which they diversified into the forms we have today through variation and evolution. Because of this fact, techniques of classification can be used to make a taxonomy of life on Earth. Smaller groups are placed within larger groups, with no overlap between them. Each group is called a taxon, plural taxa.
10.1
In taxonomy, what is the hierarchy used now?
- (D, K, P, C, O, F, G, S)
The hierarchy now used from the largest tax onto the smallest is: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.
10.1
In taxonomy, what are trees of life?
- what are they used for
Trees of life used to be solely based on physical similarities between organisms, but now we can use many other lines of evidence such as genetics, biochemistry, and the fossil record to construct phylogenetic trees to illustrate relationships.
10.1
In Classification, what are the 3 domains?
- how is a species named
Based on recent evidence, the new taxon domain comes above Kingdom. There are three domains: Bacteria, Archaea and Eukarya.
Each species is universally identified by a binomial consisting of the name of its genus and species (e.g. Homo sapiens)
10.1
What is Classification?
- when is a species name written in italics
- The genus name must always start with a capital letter, but the species name is always in lower case.
- when identifying a binomial, it is written in italics
10.2
Based on shared characteristics, what can living organisms be classified into?
Living organisms can be classified into groups based on their shared characteristics. Until recently, classification divided life into 5 kingdoms: Prokaryotes are Protoctista, Fungi, Plantae, Animalia.
10.2
What does each domain contain?
Each of the domains contain unique ribosomal RNA (rRNA)
10.2
What is Bacteria (prokaryotes)?
- describe what they are
- give an example
- They differ from Archaea as they have slightly different membranes.
- Hugely diverse and impossible to decide upon the number of species of bacteria as they can share genetic information through horizontal gene transfer.
-For example cyanobacteria
10.2
What is Archaea (prokaryotes)?
- describe what they are
- give an example
- These often inhabit extreme environments because they have adaptations in their cell membranes to withstand high temperature, pH and soil concentrations.
- They are very small in size, similar to bacteria or mitochondria.
10.2
What is Eukarya (eukaryotes)?
- describe what they are
- give an example
- These have membrane-bound organelles and are divided into 4 kingdoms, Protoctista, Fungi, Plantae, Animalia.
10.3
What is the definition of a biological species?
- A biological species is: a group of similar organisms that can breed together to produce fertile offspring.
10.3
What is the phylogenetic species definition?
- For asexual organisms (e.g. bacteria and some plants) we can use the phylogenetic species definition: the smallest group of organisms that are descended from a single common ancestor.
10.3
What is one way in which classification can be ahieved
- Classification can be achieved through comparing observable features.
10.4
What is fossilisation?
- how does it occur
- fossilisation occurs in particular conditions where hard tissues (such as bones and teeth) are replaced with minerals and sedimentary rock.
10.4
What is the fossil record?
- how is it useful
The fossil record is a useful tool to see how organisms evolve over time and when different species started to appear (e.g. Horses and humans). The fossil record is incomplete, so there are some gaps in what we know of past diversity.
10.4
What DNA evidence is used in classification?
- Comparing DNA can help determine how closely related different species are. The fewer genetic similarities, the more distantly related the species are.
10.4
What molecular evidence is used in classification?
- Like DNA, other molecules can be compared for similarities (e.g. RNA and DNA polymerase of vital enzymes that are evolved slowly over time but have been present since the earliest organisms).
10.4
What is the evidence for the theory of evolution by natural selection?
- Contribution of Darwin and Wallace.
Charles Darwin is credited with the theory of evolution by natural selection from his field work on the Galapagos Islands. Alfred Russell Wallace researched a similar conclusion at the same time from his field work in Malaysia. They later worked together, leading Darwin to publish On the Origin of Species.
10.5
What is genetic variation in a population?
In a population, not all organisms survived to be able to reproduce. Individuals die or fail to reproduce due to predation, disease or competition for resources: food, water, space, mates and environmental change.
10.5
What is natural selection?
Organisms with characteristics that allow them to survive will have a selective advantage when there is a new selection pressure, and are more likely to reproduce (high reproductive success).
10.5
What is passed onto the next generation in genetic variation?
Favourable alleles are passed onto the next generation. Those allele frequencies increase in the gene pool over many generations
10.5
What is evolution?
Evolution is the change of allele frequency within a population over time as a result of these processes.
10.5
What are the different types of variation.
- Intraspecific variation.
- Interspecific variation.
10.5
What is Intraspecific variation?
Variation between individuals within the same species.