BIO final exam 2022

Section A (12 Marks)

• Q1: Evolutionary Theory Changes Over Time

  • The chain of being hierarchy: Medieval concept placing organisms in a strict order.

  • 1800s: Naturalists began observing and classifying species more effectively.

  • Early 1900s: Darwin’s theory of natural selection became prominent but didn't fully account for genetic variation.

  • Today: Evolutionary theory integrates genetics and molecular biology to explain genetic variation in evolution.

SHORT ANSWER:

The chain 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 into 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 fro how species change over time. However, this theory did not fully account for genetic variation or 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. Overall, evolutionary theory has evolved from a rigid hierarchical view of nature to a more nuanced understanding of how biological systems work together to create diverse life forms.

Q2: Example of Adaptive Traits

• • Improved eyesight:

    • Humans: Enhanced detail perception.

    • Birds (e.g., Eagles): Exceptional sight for spotting prey.

SHORT ANSWER:

One example of a trait that has continuously improved over time is eyesight. In humans, our eyes have evolved to become more complex and efficient at detecting light and colour, allowing us to see in greater detail and with greater accuracy. Similarly, in birds such as eagles, their eyesight has also evolved to become incredibly sharp, enabling them to spot prey from great distances.

Q3: Influences on Darwin

• • WHAT HAD THE LEAST INFLUENCE ON DARWINS WORK AND WRITING?

    (a) Knowledge of inheritance by Gregor Mendel.

Section B (22 Marks)

Key Questions and Concepts

• Q4: Hardy-Weinberg Equilibrium - The Hardy-Weinberg equilibrium theory is a principle in population genetics that states that the frequency of alleles and genotypes in a population will remain constant over time if certain conditions are met.

  • Assumptions: No mutation occurs, no gene flow in or our of the population, population is large enough to avoid genetic drift, random mating and natural selection doesn’t occur.

  • Microevolutionary Processes:

    • Natural Selection: Favorable traits enhance survival.

    • Genetic Drift: Random changes in allele frequency (founder effects, bottlenecks).

    • Gene Flow: Exchange of genes between populations impacts allele frequency.

    SHORT ANSWER:

  • Microevolutionary processes can disrupt this equilibrium. Natural selection is the process by which organisms better adapted to their environment have a higher chance of surviving and reproducing than those less adapted. This leads to changes in allele frequencies over time as advantageous traits become more common in the population.

    Genetic drift is another process that can cause changes in allele frequencies. It refers to random fluctuations in gene frequencies due to chance events such as found effects (when a small group of individuals establish a new population), genetic bottlenecks (when a large population is suddenly reduced in size), or simply random mating.

    Gene flow occurs when genes are exchanged between different populations through migration. This can introduce new alleles into a population, alter existing allele frequencies, and even lead to speculating if populations become isolated from each other long enough for significant genetic divergence to occur.

    Overall, while the Hardy-Weinberg equilibrium provides an idealised model for understanding how allele and genotype frequencies change over time, it is important to consider the impact of microevolutionary processes on real-world populations.

• Q5: Which mutation is likely to become fixed?

  A beneficial mutation in a small population is strongly favoured.

• Q6: Why is an understanding of evolutionary processes so important to conservation?

  Describe, using a real or theoretical example, two key ways in which evolutionary

  information could be used to inform conservation practices.

  • Importance: Understanding evolutionary processes guides conservation decisions.

  • Example: Genetic studies of African elephants can inform population preservation.

SHORT ANSWER:

An understanding of evolutionary processes is important to conservation because it helps us understand how species have adapted to their environments over time and how they may continue to evolve in response to changes in their environment, including human impacts. This knowledge can inform conservation practices by guiding decisions about which populations or individuals are most valuable for maintain genetic diversity and adaptive potential.

For example, a study of the genetics of African elephants showed that there were distinct populations with different adaptations to their habitats. By considering these differences when creating protected areas or designing translocation programs, conservationists can ensure that the genetic diversity and adaptation potential of the species are maintained.

Another way evolutionary information can be used in conservation is through selective breeding programs. For instance, some fish populations have been selectively bred for faster growth rates, making them more resilient to fishing pressure. By using this knowledge to selectively breed other fish stocks, we could create more sustainable fisheries and help conserve threatened species.

• Q7: Anthropogenic climate change is taking place at such a fast rate that many species will fail to adapt quickly enough to avoid extinction. Which of the following may constrain evolution in response to human-induced climate change?

  • Factors: (e) Lack of heritable variation, genetic correlations, loss of variation by drift, lack of new mutations.

• Q8: FST Prediction

  • High FST (0.337): Low dispersal ability, long generation time, and small population size.

SHORT ANSWER:

Based on the FST value of 0.337 we can predict that the dispersal ability of this species is likely to be low, meaning individuals are not moving far and wide from their birthplace. This is because a high FST value indicates genetic differentiation among populations, which suggests limited gene flow due to restricted dispersal.

The generation time of this species is likely to be long as higher FST values are usually associated with longer generation times. Long generation times result in slower evolution and genetic differentiation between populations over time.

The population size of this species is likely to be small since higher FST values are often associated with smaller populations that experience more genetic drift than larger ones. Genetic drift refers to random changes in allele frequencies due to chance events like mutations or environmental factors affecting certain individuals more heavily than others.

• Q9: Guppy Selection Example

  • Predation leads to Directional Selection favoring grey-winged morphs over orange, leading to potential extinction of the orange morph.

SHORT ANSWER:

We would expect natural selection to occur in this scenario, specifically directional selection. This is because the increased predation on orange-winged butterflies creates a selective pressure that favours grey-winged butterflies. Over time, we would expect the frequency of grey-winged butterflies to increase while the frequency of orange-winged butterflies decreases. Eventually, if the selective pressure remains constant, its possible the orange-winged butterflies could become extinct in this population.

• Q10: Living mammals have similar features to those that became extinct in the Mesozoic. This is an example of…

  Convergent evolution

• Q11: Species Relationships

  • Concepts: explain outgroup, sister taxa, monophyletic and paraphyletic groups.

• Q12: Comparative Genomics Experiment

  • Steps: Compare genomes between invasive and non-invasive species to identify advantageous genes.

  • Expected findings: Unique genes aiding crop digestion in invasive species.

• Q13: Why are we able to perform experiments on model species (e.g., fruit flies and mice) to obtain information that can be applied to humans?

  • Similar genetic responses across model species (e.g., fruit flies, mice) inform human biology.

SHORT ANSWER:

Modern species share a high degree of genetic similarity with humans, particularly in their basic biological processes and molecular mechanisms. This means that the genetic and cellular responses observed in these organisms can often be extrapolated to predict similar responses in humans.

• Q14: What is ‘phylogenetic conservatism’, and how does it explain why the tuatara can be considered a ‘living fossil’?

  • Definition: Retention of ancestral traits; example: Tuatara as a living fossil with primitive features.

SHORT ANSWER:

Phylogenetic conservatism refers to the tendency of species to retain ancestral traits over long periods of evolutionary time. This means that closely related species are likely to share many physical and behavioural characteristics, even if they have diverged significantly in other ways.

The Tuatara is considered a living fossil because it has many primitive features that have remain unchanged over time. It’s ancestors were already well adapted to their environment, so there was no need for major changes in morphology or behaviour. The Tuataras isolated island habitat may have limited opportunities for diversification and adaptation compared to mainland species with more varied ecosystems.

Section D (20 Marks)

Hybridism and Gene Flow

• Q15a: Hybridism in Genera

• Q15b: Godley Hypothesis Significance

  • Implications for evolution through interbreeding of Sophora species affecting genetic diversity and conservation strategies.

Phylogenetic and Cultural Connections

• Q16: Rimu Comparison

  • Similarities: Both whakapapa and phylogeny describe evolutionary ties; hierarchical classification.

  • Differences: Whakapapa includes cultural contexts; specific to Māori; can extend beyond living organisms unlike phylogeny.

Section E (28 Marks)

Key Concepts and Predictions

• Q17: Sexual Selection for Traits

  • Process: Traits like coloration get fixed by increasing attractiveness leading to reproduction.

• Q18: Guppy Morph and Selection

  • Ecological selection favors bright colors for mate attraction; sexual selection may vary by female preferences.

• Q19: Hamilton's Rule

  • Formula illustrates natural selection favors genetic success, showing altruism benefits genetic relatives.

• Q20: Geographic Mosaic Theory of Coevolution

  • Variation sources: Special, Temporal, Genetic; examples relate to species interactions and adaptations.

• Q21: Red Queen Hypothesis Predictions

  • Traits evolve under competitive pressures leading to adaptations, illustrated by peacock tails, duck genitalia variations, and plant reproductive practices.

• Q22: Eco-Evolutionary Dynamics

  • Definitions and requirements emphasized; nature examples include guppy predation impact and finch beak adaptations through environmental shifts.

Section A (12 Marks)

Key Questions and Concepts

Q1: Evolutionary Theory Changes Over Time

• The chain of being hierarchy: A Medieval concept organizing organisms in a strict order from lowest to highest forms.

• 1800s: Naturalists enhanced the observation and classification of species, leading to greater understanding of biodiversity.

• Early 1900s: Charles Darwin's theory of natural selection gained prominence, though it did not fully explain genetic variation.

• Today: Evolutionary theory now incorporates genetics and molecular biology to detail how genetic variation occurs and influences evolution.

Q2: Example of Adaptive Traits

• Improved eyesight:

  • Humans: Enhanced ability to perceive details, aiding in survival and interaction with the environment.

  • Birds (e.g., Eagles): Exceptional vision for detecting prey from great distances, an adaptation that enhances survival.

Q3: Influences on Darwin

• Least influential: Knowledge of inheritance was first significantly detailed by Gregor Mendel, which came later and did not directly shape Darwin's ideas.

Section B (22 Marks)

Key Questions and Concepts

Q4: Hardy-Weinberg Equilibrium

• Assumptions: Conditions include no mutation, no gene flow, a large population, random mating, and no natural selection.

• Microevolutionary Processes:

  • Natural Selection: The process where favorable traits enhance survival and reproduction rates.

  • Genetic Drift: Random fluctuations in allele frequencies, which can lead to significant changes in small populations (e.g., founder effects, bottlenecks).

  • Gene Flow: Exchange of genetic material between populations, impacting allele frequencies in both groups.

Q5: Mutation Fixation Likelihood

• Likelihood Statement: Favorable mutations are more likely to become fixed in small populations due to reduced genetic noise and increased selective pressures.

Q6: Conservation Relevance

• Importance: Understanding evolutionary processes assists in making informed conservation decisions, such as the genetic studies on African elephants to inform population management strategies.

Q7: Constraints on Evolution by Climate Change

• Factors: Challenges include lack of heritable variation, genetic correlations, genetic drift leading to loss of variation, and absence of new mutations.

Q8: FST Prediction

• Interpretation: A high FST value (0.337) indicates low dispersal ability, long generation times, and small population sizes, leading to genetic differentiation.

Q9: Guppy Selection Example

• Directional Selection: Predation pressure leads to selection favoring gray-winged guppy morphs over orange ones, potentially indicating an extinction risk for the latter.

Section C (18 Marks)

Key Questions and Concepts

Q10: Mesozoic Extinction Reference

• Comparative Analysis: Study of characteristics common between living mammals and extinct Mesozoic organisms to illustrate patterns of divergent evolution.

Q11: Species Relationships Concepts

• Definitions:

  • Outgroup: A species or group closely related to but not part of the group being studied, helps to establish evolutionary traits.

  • Sister taxa: Two lineages that share a common ancestor and diverged from it.

  • Monophyletic Group: A group consisting of an ancestor and all its descendants.

  • Paraphyletic Group: A group that includes some but not all descendants of a common ancestor.

Q12: Comparative Genomics Experiment Steps

• Methods: Compare genomes of invasive versus non-invasive species to pinpoint advantageous genes that facilitate adaptive traits.

• Expected Findings: Identification of unique genes that enhance abilities such as crop digestion in invasive species.

Q13: Model Species

• Genetic Responses: Observations of genetic responses in model organisms (e.g., fruit flies and mice) provide insights relevant to human biology.

Q14: Phylogenetic Conservatism

• Definition and Example: Retention of ancestral traits observed in species like the Tuatara, which exhibits features akin to early reptiles.

Section D (20 Marks)

Hybridism and Gene Flow

Q15a: Hybridism in GeneraQ15b: Godley Hypothesis Significance

• Context: Investigates the evolutionary implications of interbreeding within Sophora species on genetic diversity and conservation strategies.

Phylogenetic and Cultural Connections

Q16: Rimu Comparison

• Similarities: Both whakapapa and phylogeny reflect evolutionary relationships and hierarchical classifications.

• Differences: Whakapapa incorporates cultural contexts and is specific to Māori, while phylogeny typically addresses biological relationships.

Section E (28 Marks)

Key Concepts and Predictions

Q17: Sexual Selection for Traits

• Process Overview: Sexual selection helps fix traits like coloration through increased attractiveness, enhancing reproductive success.

Q18: Guppy Morph and Selection

• Ecological Effects: Ecologically favorable traits, such as bright colors, enhance mate attraction; however, sexual selection may differ based on female preferences.

Q19: Hamilton's Rule

• Implication: Demonstrates how natural selection favors traits that enhance genetic success, promoting altruistic behaviors towards genetically related individuals.

Q20: Geographic Mosaic Theory of Coevolution

• Variation Sources: Considers special, temporal, and genetic variations impacting species interactions and adaptations.

Q21: Red Queen Hypothesis Predictions

• Adaptive Evolution: Traits evolve respond to constant competitive pressures, illustrated by diverse adaptations in peacock tails, variations in duck genitalia, and plant reproductive strategies under similar pressures.

Q22: Eco-Evolutionary Dynamics

• Definitions and Examples: Highlights the requirements for eco-evolutionary dynamics with practical instances, such as guppy predation impacts and finch beak adaptations due to environmental shifts.