Ethics and Continuity in Population

The final showdown - ethics and continuity in population explained in a NUTSHELL!

Reproduction

Process of producing offsprings of a species.

Variation

Differences between members of a population in one or more traits of their phenotypes.

👉 The method of reproduction (sexual or asexual) determines how much variation a species will have.

Sexual Reproduction in Humans

• Fertilisation occurs internally in the female.

• Female gamete (ovum) + Male gamete (sperm) → zygote.

• Gametes have 23 chromosomes each (haploid).

• Zygote has 46 chromosomes (diploid) since 23 + 23 = 46.

• Gametes are produced in gonads by meiosis.

• Benefit: Produces variation in offspring.

Advantages/Disadvantages of Sexual Reproduction

Advantages:

• Creates variation → better adaptation

• More disease/environment resistant

• Drives evolution

Disadvantages:

• Only half of genes passed on

• Needs a mate → slower reproduction

• Slower population growth

Asexual Reproduction

• Mode of reproduction where offspring are produced by a single parent.

• Offspring are genetically and physically identical → NO variation.

Asexual Reproduction Advantages/Disadvantages

• Advantages:

  • Offspring are genetically identical—good if parent is well-adapted.

  • Population can grow rapidly in optimal conditions.

  • Time- and energy-efficient; some bacteria reproduce in ~20 min.

  • Quick process; no need for a partner.

• Disadvantages:

  • Lack of genetic variation → poor adaptability to environmental changes.

  • Faulty genes are passed on.

  • Rapid growth can cause competition for resources.

  • Entire population at risk if disease or environmental challenge occurs.

Types of Asexual Reproduction

• Binary fission – in prokaryotes (e.g. bacteria).

• Budding – outgrowth develops, separates into new individual (e.g. corals, hydras).

• Fragmentation – parent breaks into fragments, each grows into new identical organism.

• Vegetative propagation – new plant from fragment/specialised structure (not all plants can do this).

• Parthenogenesis – female produces unfertilised eggs that develop into embryos without sperm.

Cloning

Technique used to create exact genetic replicas of genes, cells, or animals.

Types of Cloning

• Artificial cloning – production of clones through human intervention, from genes to whole organisms.

• Natural cloning – occurs naturally (e.g. identical twins).

Cloning Techniques in Horticulture (园艺)

• Cutting – cut a small stem to grow a new plant.

• Artificial propagation – cut the main stem to produce new plants.

• Plant tissue culture – grow new plants from small groups of cells in controlled lab conditions.

Artificial Cloning in Agriculture

Technique	Process	Individuals Involved	Key Point / Benefit
Embryo Splitting (胚胎分裂)	Early embryo (from in vitro fertilisation, IVF 体外受精) is split in a petri dish; identical embryos implanted into surrogate mothers.	1 egg donor + 1 sperm donor + multiple surrogates	Increases number of offspring per season.
Somatic Cell Nuclear Transfer (SCNT, 体细胞核移植)	Remove nucleus from unfertilised egg, replace with nucleus from adult somatic cell, implant into surrogate (代理) mother.	1 egg donor + 1 somatic cell donor + 1 surrogate	Produces a true clone of the donor (e.g. Dolly the sheep 🐑).

Ethics of Cloning

• Safety & efficacy (功效): Often inefficient; many embryos fail.

• Health risks: Clones may suffer or die.

• Environmental impact: Can affect other organisms and ecosystems.

• Moral concerns: Violates ethical principles.

Causes of Variation

• Reproduction: Sexual → high variation; Asexual → low/no variation.

• Gene Mutation: Change in DNA base sequence; introduces new alleles; only inherited if in germline cells.

• Environment: Selection pressures; via epigenetics, genes can be switched on/off; some epigenetic marks may be inherited.

Variation

Important for a population to survive any sudden change in their environment.

Adaptation

• Enables an organism to reproduce and survive in its environment.

• Result of genetic variation, especially natural selection.

• Organisms cannot consciously adapt; adaptations arise through natural selection.

Natural Selection

• Variation & mutations create favourable traits in some organisms.

• These traits help organisms survive selection pressures.

• Favoured traits are passed to offspring, increasing allele frequency.

• Result: More individuals show the favourable phenotype, boosting survival chances.

Types of Adaptations

• Structural: Anatomical/morphological features; physical structures that adapt to the environment.

  • Example: Camel’s hump

• Behavioural: Actions that help the organism survive and reproduce in its habitat.

  • Example: Bird migration

• Physiological: Internal functions; biochemical to cellular to tissue level, allowing special functions for survival and reproduction.

  • Example: Venus flytrap trapping insects

Ecosystem

Interactions between biotic and abiotic factors in a geographic area.

Niche

• An organism’s role within an ecosystem.

• Includes physical/environmental conditions it needs and interactions with other species.

• Some organisms may have a narrow/limited niche.

Biotic Factors

• Living things in an ecosystem.

• Interdependent relationships exist.

• Competition:

  • Interspecific: Between different species for the same resource.

  • Intraspecific: Between individuals of the same species for the same resource.

Abiotic Factors

• Non-living things in an ecosystem.

• Examples: pH, light availability, temperature, etc.

Feeding Relationships—Autotrophs & Heterotrophs

• Autotrophs: Make their own glucose by converting light energy (e.g., plants).

• Heterotrophs: Obtain energy by eating other organisms; convert it to ATP via cellular respiration.

Relationships in Ecosystems

• Autotrophs / Producers: Produce energy via photosynthesis/chemosynthesis.

• Heterotrophs / Consumers:

  • Herbivores: Eat plants only

  • Omnivores: Eat plants & animals

  • Carnivores: Eat animals only

  • Scavengers: Eat dead animals

  • Detritivores: Eat waste

• Parasites: Take energy/nutrients from hosts, usually harming them.

• Decomposers: Break down dead matter into molecules.

Food Chains

• Show energy transfer from low → high trophic level (营养级).

• Arrows indicate energy flow, NOT “who eats who.”

• Categorised into producers and consumers, arranged from producer → consumer.

Food Webs

• Arrows show energy transfer.

• Energy generally flows upward, except decomposers.

• Organisms lined up by trophic level.

• Categorised into producers and consumers.

• Note: can have primary/secondary/more for each trophic level, such as primary and secondary consumers, etc.

Indigenous Perspectives

• Strong connection with land.

• Country/place: Land where Aboriginal people belong.

• Spiritual essence: Ancestors’ spirit remains in landscape, sky, water.

Ecosystem Knowledge for Indigenous Australians

• Applied in various aspects, e.g., medicine, especially bush medicine.

• Helps communities survive and thrive in harsh environment.

Biomimicry for Native Australians

• Using advantageous adaptations from nature for human applications.

• Example: Stingray’s barb/stinger (on tail, sharp point, back, serrations) inspires design solutions.

Bushfires

• Abiotic factor affecting interrelationships in ecosystems.

• Uncontrolled fires: Prolonged, high-intensity burns destroy organisms and habitats, often irreversibly.

• Controlled/managed fires: Not necessarily detrimental (有害的); used by Indigenous people for land management.

• Benefits: Facilitates plant growth and distribution, and promotes suitable habitats for fauna.

Low-Intensity Fires / Cool Burning

• Used by Indigenous Australians for land management.

• Returns nutrients to soil via ash.

• Promotes germination of fire-dependent species.

• Encourages suitable habitats for animals.

• Clears country to prevent fuel buildup.

• European disruption of this practice led to loss of biodiversity.

Germination

Requires:

• Water

• Oxygen

• Optimal temperature (for enzymes)

• Light

All conditions needed for seed to sprout.

Population

Group of individuals of the same species in a particular area.

Distribution

Geographic range of individuals in a population.

→ Depends on resource availability.

Abundance

Actual number of individuals in a population.

→ Depends on resource availability.

Density

Number of individuals in a given area.

Factors Affecting Populations

• Density-Independent Factors

  • Affect population regardless of size/density.

  • Example: Natural disasters.

• Density-Dependent Factors

  • Influence population based on size/density.

  • Examples: Competition, predation, crowding, disease.

Predator-Prey Relationships

• One animal kills and feeds on another.

• Prey density ↑ → predator density ↑ (more food).

• Prey density ↓ → predator intraspecific competition ↑ → predator population ↓.

Carrying Capacity of an Ecosystem

• Maximum population size a species can be sustained by an ecosystem.

• Limited by factors like food, resources, and disease.

• Without limits, populations may show exponential growth.

• Introduced species can impact ecosystems → interspecific and intraspecific competition.

• Populations often self-regulate around carrying capacity.

Ethical Approaches 1

Consequence Based Approach

• Focus: Outcomes.

• Best overall result for the most people.

• Minimise negative effects, even if act itself isn’t “right.”

• Example: Sacrificing one life to save many.

Ethical Approaches 2

Duty and/or Rules Based Approach

• Focus: Duties & rules.

• Follow laws, rules, moral duties.

• Consequences don’t matter.

• Example: Never lie, even if lying saves lives.

Ethical Appraoches 3

Virtue Based Approach

• Focus: Moral character.

• Act as a good/virtuous person would.

• Based on virtues, not rules or outcomes.

• Example: Acting with honesty, courage, kindness.

Integrity

• Actions involve truth & trustworthiness.

• Honest action in the situation.

• Promises that must be kept.

• Maintaining trust.

• Conduct of stakeholders considered.

• Check if ethical standards have been breached.

Beneficence

• Actions aim for positive outcomes, minimising harm.

• Maximise benefits to others.

• Choose actions with more benefit than harm.

• Prioritise those needing the most help.

• Strive to even the playing field.

Justice

• Actions involving fairness

• Consider effects of actions on others: is it fair?

• Ensure equal access to benefits.

• Minimise disadvantages caused by actions.

• Treat all stakeholders equally, avoid unfair burdens.

• Recognise all stakeholders, avoid exclusion.

Non-Maleficence

• Avoid actions that cause harm.

• Identify risks of each action.

• Choose the option causing the least harm.

• Avoid harming others where possible.

• Select the safest option.

Respect

• Consider autonomy of all living beings.

• Recognise what they feel, think, and need.

• Choose actions that least interfere with others’ views, customs, beliefs, liberty, welfare.

• Minimise impact on others’ needs and autonomy.

• If someone cannot decide for themselves, ensure their protection.