Extreme Biology 1 - Non Human

Extreme Bacteria, Viruses, Parasites and Animal adaptations in tough climates and human impact

Extremophiles

Organisms that grow optimally in environments considered extreme and have thrived throughout Earth's history.

Candidatus Pelagibacter ubique

An ultramicrobacterium found in salt and freshwater globally; possibly the most abundant bacterium on Earth.

Epulopiscium spp

Exceptionally large bacteria that maintain size through membrane folding and genome arrangement.

Bacterial growth rate

Varies widely from multiple times per hour to once per year depending on environmental conditions.

Growth rate limitation

Determined by ribosomal abundance and translation efficiency.

Archaea

Prokaryotes similar to bacteria but genetically closer to eukaryotes; do not form endospores.

Thermophiles

Bacteria that thrive at temperatures between 41°C and 122°C with rigid, thermostable enzymes.

Psychrophiles

Cold

Xerotolerant bacteria

Bacteria that survive dry conditions through spore formation, osmoprotectants, and DNA repair proteins.

Acidophiles

Bacteria that thrive at pH <2 using K⁺ antiporters, chaperones, and DNA repair proteins.

Alkaliphiles

Bacteria that thrive at pH >8.5 using H⁺ antiporters, Na⁺ uptake systems, and cytochromes.

High pressure adaptation

Bacteria adapt to deep

Polyextremophiles

Organisms that can survive multiple extremes like cold, vacuum, acid, radiation, and UV.

Physical limits to life

Defined by environmental extremes such as temperature, pressure, pH, and nutrient availability.

Environmental adaptation

Achieved by increasing gene copy number without losing irrelevant genes.

Protein thermostability

Achieved through increased rigidity in hyperthermophilic enzymes.

Cold survival strategies

Include cold shock proteins, antifreeze proteins, and membrane fluidity enhancers.

Dry survival strategies

Include spore formation, osmoprotectants, and extracellular polymeric substances.

pH survival strategies

Include ion transport systems and protective proteins for acid or alkaline environments.

High pressure survival strategies

Include structural proteins, motility adaptations, and metabolic shifts.

Importance of extremophile research

Benefits medicine, climate change, bioremediation, and space science.

Applications of extremophiles

Used in PCR, biosensing, bioprocessing, and astrobiology.

Studying extreme bacteria

Involves collecting, culturing, sequencing, gene knockout, and protein structure analysis.

Earth as bacterial habitat

Bacteria are found in diverse environments from volcanoes to subglacial lakes.

Human driven impacts

Includes habitat fragmentation, hunting/harvesting, climate change, and pollution.

Habitat fragmentation

The breaking up of habitats into smaller patches due to natural or human causes.

Natural fragmentation

Habitat disruption caused by natural events like flooding or earthquakes.

Anthropogenic fragmentation

Habitat disruption caused by human activities such as deforestation.

Population biology effects

Fragmentation affects population connectivity, with isolated populations being more vulnerable.

Specialist species

Animals that rely on specific resources and are heavily impacted by habitat fragmentation.

Generalist species

Animals that can use a variety of resources and are more adaptable to fragmentation.

Carnivore vulnerability

Carnivores are more affected by habitat loss due to low densities and large home ranges.

Linear features

Roads, fences, and powerlines restrict animal movement and increase mortality and stress.

Fragmentation positives

Roads can aid travel and foraging, and help trap prey or scavenge.

Tasmanian Devil and Spotted Tail Quolls

Generalist carnivores that adapted to fragmentation with faster road movement.

Hunting and harvesting

Human exploitation affects animal morphology, behavior, and life history traits.

Selective harvesting

Disrupts natural selection and delays population recovery.

African elephants and ivory trade

Poaching led to evolution of smaller tusks and changes in body size.

Climate change impact

Niche evolution is 10,000x slower than needed to match climate projections.

Species vulnerability factors

Exposure, sensitivity, resilience, and ability to adapt determine climate change impact.

Range shift adaptation

Species may shift their distribution to stay within climate

Marine mammal challenge

Rapid climate shifts challenge the adaptability of marine mammals.

Ice obligate species

Species like polar bears and penguins that depend entirely on ice habitats.

Ice associated species

Species that rely on ice but not exclusively.

Seasonally migrant species

Species like whales that follow seasonal food sources and may benefit from ice loss.

Genetic composition adaptation

Microevolution leads to heritable changes like coat color for thermal regulation.

Springbok coat color

Darker coats absorb more heat, reducing metabolic costs in cooler climates.

Phenotypic plasticity

A single genotype produces different traits depending on environmental conditions.

Epigenetic effects

Environmental changes affect individual traits without altering future generations.

Climate change responses

Animals may acclimate, acclimatize, or learn to cope with new conditions.

Extinction risk

Species unable to adapt may face local or global extinction.

Parasite

An organism that lives on or in another organism and benefits by deriving nutrients at the other's expense.

Climate change and parasites

Global warming expands the range of parasitic diseases, especially those spread by mosquitoes.

Global temperature rise

Average global temperature has increased by 1.5°C since 1850 due to human activities.

Malaria

A mosquito

Mosquito and malaria development

Higher temperatures accelerate Plasmodium development, increasing transmission risk.

Malaria symptoms

Parasites burst liver cells and infect red blood cells, causing fever and potentially fatal brain blockage.

Ronald Ross

Scottish scientist who discovered mosquitoes transmit malaria, but did not credit collaborators.

Economic impact on disease

Infectious disease rates inversely correlate with economic prosperity; funding is key for interventions.

Lancet Fluke (Dicrocoelium)

Parasite spread by ants; involves cows, snails, and ants in its life cycle; can infect humans.

Toxoplasmosis

A parasitic infection with cats as the definitive host; dangerous for pregnant women and immunocompromised individuals.

Toxoplasmic encephalitis

A life

Toxoplasmosis and behavior

Infected mice show reduced fear of cats; human risk

Tongue eating louse (Cymothoa exigua)

Parasite that replaces the tongue of fish by feeding on it and acting as an artificial tongue.

Patrick Manson

Scottish scientist who proved filarial worms are transmitted by mosquitoes through experiments on his gardener.

Lymphatic filariasis (Elephantiasis)

Nematode infection causing limb swelling due to lymphatic fluid buildup; treated with Ivermectin.

Sleeping sickness (African trypanosomiasis)

Caused by protozoa from tsetse fly bites; affects brain and sleep patterns; can be fatal.

Eflornithine

Drug that treats sleeping sickness; later found useful for hair removal, prompting drug development initiatives.

Parasite transmission

Parasites spread through vectors like mosquitoes, ingestion, and contact with infected hosts.

All organisms carry parasites

Every living organism hosts multiple parasites, often without symptoms.

Animal and human infection

Many parasites infect both animals and humans, crossing species boundaries.

Parasite treatment

Some drugs exist, but many parasitic diseases require new treatments and drug development.

Scottish contributions to parasitology

Scottish scientists like Ronald Ross and Patrick Manson made key discoveries in parasite research.

Giant impact hypothesis

Theory that Earth collided with a Mars

Biomes

Regions defined by similar flora and fauna; extreme biomes include ice, snow, tundra, taiga, and deserts.

Obligate annual migration

Animals migrate to the same location each year to avoid harsh seasonal conditions.

Irruptive migration

Opportunistic animal movements based on local environmental conditions.

Partial migration

Only part of a population migrates while others remain; typically annual and regular.

Subnivean zone

Snow layer used by small/medium animals for insulation during winter, maintaining around 0°C.

Sheltering in snow

Small animals use snow for warmth; large animals cannot fit and do not shelter this way.

Blood flow modulation

Animals regulate heat by adjusting blood flow to surface or through vasodilation.

Heat exchangers

Counter

Endothermic fish

Use regional heterothermy to keep muscles, brain, and eyes efficient in cold water.

Endothermy in water

Energetically expensive due to water’s thermal properties compared to air.

Frozen fish risk

Marine fish blood has lower osmotic concentration than seawater, risking freezing in polar seas.

Antifreeze proteins

Proteins that bind to ice crystals to prevent freezing; evolved independently in fish and insects.

Homeotherms

Animals with high metabolic rates that require more energy, especially in cold climates.

Torpor

Short

Hibernation

Long

Managing heat

Animals in hot climates use evaporation, reflection, insulation, and refuges to avoid overheating.

Water acquisition in deserts

Darkling beetles collect fog droplets using textured wing surfaces.

Thermophilic scavengers

Live in extreme heat (up to 70°C); use short foraging trips, elevated surfaces, and reflective hairs.

Dead reckoning navigation

Thermophilic scavengers use internal solar compass and step counting to return to nests.

Virus

A small parasite that cannot reproduce on its own but hijacks host cell machinery to replicate.

Porcine circovirus

One of the smallest known viruses, measuring just 17 nanometers in diameter.

Viroids

Infectious agents in plants made of 250–400 nucleotides; lack proteins and are extremely small.

Mimiviruses

Large viruses with double

Virus species count

As of 2024, there are 16,213 known virus species, though many remain undiscovered.

Virus prevalence in environments

Found in high numbers: 1000 genotypes in human faeces, 5000 per 200L of water, up to 1 million in marine sediment.

Human infection by viruses

451 virus species are known to infect humans, but transmission barriers limit constant infection.