Macro-evolution questions and answers
Define the Biological species concept, explain one instance where it doesn’t work well, define the other species concept and why it works better.
The BSC describes a small group of organisms who can interbreed and produce fertile offspring, while maintains reproductive isolation from other groups. However, this does not work well for asexual organisms as they don’t need mates for reproduction and don’t form tradition reproductive barriers. The PSC describes a species as the smallest of organisms that share a common ancestor and are distinct from other species based on evolutionary history. The PSC works well for asexual organisms as it doesn’t rely on sexual reproduction. However, it can be hard to apply in some cases, especially when populations are too genetically similar but not clearly distinct.
Guppy morph and selection. Ecological selection VS sexual selection.
Ecological selection in a Trinadian stream could affect different male morphs of guppies by favouring the bright coloured morphs over drab ones. This is because bright colours may help attract females and deter predations, while drab colours may make them more vulnerable.
Sexual selection, however can favour either bright coloured or drab coloured morphs, based on female preference. Females may prefer males with bright colours as it suggests health, survival and reproductive fitness. Alternatively, they may prefer drab males who are able to blend into their environments, increasing their chances of survival.
If ecological selection dominates then we would expect the frequency of bright coloured morphs to increase and they would be dominant within the population. If sexual selection dominates and female preference is bright coloured morphs then we would expect the same outcome. However, if the female preference shifted to drab males then we would expect the frequency of this trait to increase meaning that the drab males would be dominant in the population.
Describe how traits like bright colours and ornamentation may become fixed and name the process.
In this scenario, the process where traits like bright colours and ornamentation can become fixed in a population is called sexual selection. This occurs when individuals with certain desireable traits are more likely to attract mates and pass on these traits to their offspring. In this case of bright colours and ornamentation can suggest health, survival and reproductive fitness to potential mates. Over time, as individuals with these traits continue to sexual mate and produce offspring, the frequency of this trait increase in the population until it becomes fixed.
Phylogenetics/tree of life
Describe two similarities and three differences of Whakapapa and phylogeny.
Both whakapapa and phylogeny use a hierarchical system that categorises organisms. They also both describe the evolbetweeen relationships between organisms. Whakapapa is specific to Maori culture, whereas phylogeny is a universal scientific concept used by biologists globally. Whakapapa includes spiritual and cultural relationships betweeen organisms, whereas phylogeny only considers biological relationships based on evolutionary history. Whakapapa includes non living entities such as mountains and rivers, whereas phylogeny only focuses on living organisms.
Examine the figure (phylogenetic tree)…
The shark would be the otugroup, representing a lineage that diverged earlier than any other species in the tree. The humans and cats would be the sister taxa, indicating that they both share a more recent common ancestor than either do when any other species in the tree. The group consisting of the humans, cats and goose would be the monophyletic group, indicating a common ancestor and all of its descendants. The group consisting of lizard, shark and frog would be the paraphyletic group, indicating a common ancestor but not all of its descendants.
How do we read a phylogenetic tree?
What mistakes to avoid.
A phylogenetic tree illustrates the evolutionary relationships between species or other taxa. The tree consists of branchesrepresenting evolutionary paths, with nodes indicating common ancestors. Tips or leaves represent the current species or taxa. The root is the common ancestor of all species on the tree, while internal nodes represent ancestors of species further up the tree. Species that are closer together on the tree are more closely related, and those sharing a common nodeare considered sister taxa. The tree can be read from root to tip, showing how species diverged over time. Clades are groups that include a common ancestor and all its descendants. Phylogenetic trees help visualize the evolutionary history of species, illustrating their relatedness and the paths they took to evolve into their current forms.
When reading a phylogenetic tree, avoid confusing branch length with time or genetic distance unless the tree specifies that it represents such information. Don't interpret a branch as a direct ancestor; instead, nodes represent common ancestors. Be careful not to misinterpret the root as the oldest species—it's the common ancestor of all species on the tree. Phylogenetic trees aren't always linear, so don’t assume evolution occurred in a straight line. Polytomies indicate unresolved relationships, so don’t assume equal evolutionary distances between branches emerging from them. Lastly, proximity on the tree shows relative relatedness, but not necessarily immediate evolutionary ancestry. Understanding these points helps avoid misinterpretation of evolutionary relationships.
Describe one key application of phylogenies.
One key application of phylogenies is in tracking the spread of diseases. By looking at the genetic responses between different strains of a virus or bacteria, scientists can see how the disease spread over time and where new outbreaks came from.
Explain what Darwin is showing in his sketch. What’s the significance?
The tree of life sketch is a diagram that shows the evolutionary relationships between organiIt’s It depicts a branching treee with various branches, representing groups of organisms, with each branch indicating a common ancestor and its descendants. It illustrates how species evolve and diverge over time. This was the first visual representation of evolution by common descent. It’s significance lies in the idea that all life is related through shared ancestry, forming the foundation for modern evolutionary biology.
Give an example of a trait that has continuously improved over time from two species.
An example of a trait that has continuously improved over time is eyesight. In humans, our eyes have evolved to more efficient and complex at detecting light and colour, allowing us to see in greater detail and with more accuracy. Similarly, in birds, such as eagles, their eyes have adapted to their environments and evolved to be more sharp, enabling them to spot prey from greater distance
Systematic biology underpins all of biology. Briefly explain what systematics is and give three examples of its importance in modern biology today.
Systematic biology, or systematics, is the scientific study of biological diversity and the evolutionary relationships among organisms. It involves the identification, classification, and phylogenetic analysis of species, integrating data from genetics, morphology, ecology, and evolutionary history to understand how life is related and has diversified over time.
Conservation biology: Systematics informs the identification of distinct evolutionary lineages, helping prioritize species and populations for conservation based on genetic distinctiveness and evolutionary significance.
Medical research: Phylogenetic analysis allows researchers to trace the origins and evolutionary pathways of pathogens (e.g., viruses or bacteria), enabling better predictions of disease emergence and the development of treatments.
Agriculture and biosecurity: Accurate species identification through systematics supports pest management and helps prevent the spread of invasive species, ensuring food security and ecosystem stability.
Aotearoa has a unique biota: Give 5 factors and briefly explain them.
Geographical isolation - caused species to evolve independently, leading to high endemism
Human arrival - introduced predators and caused extinctions and or adaptations
Absence of land mammals - lead birds to fulfil mammal-like roles, resulting in many flightless species
Tectonic uplift and volcanism - created new environments and promoted speciation
Diverse climates - supported many habitats and species from alpine to subtropical
There is a line of thought that suggests that evolution is predictable.
Give an example that both supports and refuses this line of thought.
Then provide your opinion on this issue and explain your reasoning.
Because genetic mutations are known to arise at random, evolution is widely seen as unpredictable. However, extraordinary patters on recurring convergent evolution has been seen, such as the loss of pigmentation by cave-dwelling species.
A few studies have suggested that organisms evolve in the same way when exposed to the same environmental conditions. A glaciers receded, fro example, a tiny marine fish known as stickleback colonised several lakes and rivers, becoming sleeker with less body armour in each location.
Evolutions only predictability is that it will still occur. When a species environment changes, one of two things happens: the species either evolves to meet the difficulties of the new environment or becomes extinct. This holds true for all species, including ours. Adaptation to one’s environment is critical to species survival, and I believe it is the most importantly component of all living species. To forecast where evolution will lead any species, one must first be able to foresee the changes in the environment that will need adaptation, and then must change in order to increase the species chances of survival. I don’t think we can reliably foresee both of these things at the same time.
Describe one key application of phylogenies.
Explain what the application is, and then what it can tell us.
One key application of phylogenies is in tracking the spread of diseases. By looking at the genetic relationships between different strains of a virus or bacteria, scientists can see how the disease has spread over time and where new outbreaks came from. For example, during the COVID-19 pandemic, phylogenetic trees were used to understand how different variants of the virus spread globally. This helps scientists understand how pathogens evolve and spread, which is important for controlling outbreaks and developing vaccines.
Describe the four aspects considered necessary for eco-evolutionary dynamics to
take place.
Four aspects organization necessary for eco-evolutionary dynamics to take place include:
Reciprocal Feedbacks: Ecological interactions influence evolutionary processes, and vice versa. Changes in the environment can drive evolutionary change, while adaptations can modify ecological interactions.
Time Scale: The processes must occur over similar time scales, allowing ecological changes to influence evolutionaryorganizations and vice versa.
Spatial Scale: Variability in environmental conditions across different habitats can lead torganizationevolutionary pathways among populations, influencing local adaptation.
Population Structure: The organization of populations in terms of genetics and social structure can affect how adaptations spread through populations and how ecological interactions evolve.
Explain why systematist think that the name ‘fish’ is misleading.
Most systematists today use classifications that reflect monophyletic groups, meaning groups that include a common ancestor and all its descendants. The term "fish" is considered misleading because it doesn’t represent a true monophyletic group. Fish are spread across several different evolutionary branches, making them more of an artificial category than a natural, evolutionary one. For example, tetrapods (like amphibians, reptiles, birds, and mammals) are actually descended from fish, but they aren't typically classified as fish. Therefore, using "fish" as a single group doesn’t accurately reflect the evolutionary relationships between species.
Use the phylogeny of Finches to explain the relationships in this hypothesis of evolutionary relationships of Darwin's finches. Is the informal classification congruent with the phylogeny? Are any taxonomic revisions required?
The phylogeny of Darwin's finches suggest that all 14 species evolved from a common ancestor with several divergences occurring over time. The three main branches in the phylogenetic tree represent ground finches, tree finches and warbler finches. Within the ground finches, there is a clear split between the medium ground finch and the small ground finch. On the other hand, within the tree finches, there is a close relationship between the small tree finch and the large tree finch. The warbler finches are more complex, with several subgroups branching off at different points. However, it is worth noting that one of these subgroups includes both the vegetarian finch and cactus finch which were previously thought to be distinct genera. Overall, the informal classification of Darwin's finches is mostly congruent with this phylogeny. However, as mentioned above, some taxonomic revisions may be required to reflect new information about evolutionary relationships.
Explain how evolutionary theory has changed over time using four key ideas from the chain of being, through the 1800s, the early to mid 1900s, to today.
The chains of being was a medieval concept that placed all living things in a hierarchical order with humans at the top and plants at the bottom. This idea persisted in the 1800s when naturalists began to observe and classify species based on physical characteristics.
In the early 1900s, Darwin's theory of natural selection gained acceptance as an explanation for how species change over time. However the theory did not fully account for genetic variation of the role of chance events in evolution.
Today evolutionary theory incorporates ideas from genetics and molecular biology to explain how genetic variation drives evolution through natural selection.
Describe how the Godley hypothesis relates to the Sophora genus and what the significance of the hypothesis is for the evolution of relevant species in the genus chosen.
The Godley hypothesis suggests that hybridisation between Sophora species may have played a significant role in their evolution. If this hypothesis is proven, it would imply that interbreeding and gene transfer among different species of Sophora could lead to the emergence of new tratoSophorave genetic variation witoSophorave genetic variation within and among Sophora.
This finding could have important implications for understanding how plant diversity arises through processes such as hybridisation and introversion. It could also inform conservation efforts by highlighting the need toSophorave genetic variation within and among Sophora species to maintain their evolutionary potential.
Comment on the extent and significance of hybdrism and polyploidy for the genera Coprosma.
In the genus Coprosma, both hybridism and polyploidy play significant roles in its evolution. Hybridism occurs when different species within the genus interbreed, producing offspring with mixed traits, leading to increased genetic diversity and potentially contributing to speciation or introgression. This process is important in areas where species overlap, fostering adaptive evolution. Polyploidy, the condition of having multiple sets of chromosomes, also occurs in Coprosma, often following hybridization. This can lead to instant speciation, where polyploid individuals are reproductively isolated from their diploid relatives, creating new species. Both hybridism and polyploidy contribute to the genus's genetic flexibility and ability to adapt to various environmental conditions, making them significant evolutionary processes in Coprosma.