Understanding Biodiversity: Ecosystems, Species, and Genetics

• Biodiversity is a fundamental concept in biology, exploring the variety of life forms.
• It spans ecosystems, species, and genetics.

What is Biodiversity?

• Diversity stems from the term 'biological diversity'.
• Biodiversity encapsulates the vast variety and variability of life.
• It delves into the complex interactions and interrelationships between life forms and their environments.

Dimensions of Biodiversity

• Biodiversity encompasses multiple dimensions, painting a comprehensive picture of life's variety.
• Ecosystem diversity includes habitats, biotic communities, and ecological processes within the biosphere.
• Habitats are specific areas where species live and reproduce, varying from deserts to tundras.
• Biotic Communities are interacting organisms like producers, consumers and decomposers in a habitat.
• Ecological Processes refer to cycles and interactions like nutrient cycling and food webs.
• Tropical Rainforests are biodiversity hotspots with species coexisting.
• Coral Reefs, known as the "rainforests of the sea", are underwater ecosystems teeming with life.
• Species diversity captures the number of different species and the balance of populations in a region.
• Species Richness details the count of species present in a region.
• Species Evenness delves into the balance of different species populations, highlighting abundance or scarcity.
• A rainforest may have species richness, while a grassland has a balanced population distribution, indicating evenness.
• Genetic diversity hones in on the variety of genes within individual species, focusing on the genetic code.
• Genetic diversity is pivotal for adaptation, meaning species have a better chance of survival faced with shifts.
• Human genetic diversity includes skin color, height, and disease susceptibility.

Importance of Biodiversity's Dimensions

• Each facet contributes to planetary equilibrium and resilience.
• Ecosystem diversity ensures that if one faces a disturbance, others can still sustain life and provide ecosystem services.
• Varied ecosystems support diverse niches and habitats for many species.
• Species diversity offers robust resistance to potential threats like diseases and pests.
• Ecological balance ensures stability through the roles of predators, herbivores, pollinators and decomposers.
• Genetic variability safeguards against abrupt environmental changes so individuals can survive.
• Genetically diverse populations have a lower risk of being decimated by a single disease.

Interconnections between Biodiversity's Dimensions

• Ecosystems nurture species, housing species adapted to thrive there.
• Species uphold ecosystems, maintaining equilibrium through activities and interactions.
• Predators control prey, herbivores influence plants, and decomposers ensure nutrient cycling.
• Genetic diversity safeguards species, enabling them to adapt and evolve.

Comparisons Between Current Number of Species and Past Levels

• Millions of species have been discovered and named.
• Many more species remain to be discovered.
• Fossils suggest there are more species alive today than at any time.
• Classification can be classified in patterns i.e. splitters and lumpers in a taxonomic group.
• To appreciate the scale of biodiversity, delve into the past and present to understand its changes.

Historical Biodiversity: Delving into Deep Time

• Biodiversity offers a chronicle of evolution, survival, and extinction.
• Analysing species richness disparities between today and the past provides insight into biological changes.

The Fossil Record

• The fossil record it acts as a historical archive documenting life from billions of years ago.
• It chronicles evolutionary milestones, adaptive radiations, and extinction events.
• It provides clues about environmental conditions, ecological niches, and interspecies interactions.

Geological Eras and Their Biodiversity Signatures

• Precambrian Era (4.6 billion - 541 million years ago)
  • Started with simple, unicellular prokaryotes.
  • Oxygenation led to multicellular eukaryotes.
  • Ediacaran biota included early complex organisms.
• Paleozoic Era (541 - 252 million years ago)
  • Cambrian explosion saw an increase in animal phyla.
  • The Devonian period saw plant colonization.
  • The Carboniferous period was known for coal forests and winged insects.
• The Permian Extinction eradicated marine species and reshaped ecosystems.
• Mesozoic Era (252 - 66 million years ago)
• Characterized by reptiles, including dinosaurs.
• Evolution of mammals and birds.
• The Cretaceous-Paleogene event caused the downfall of non-avian dinosaurs.
• Cenozoic Era (66 million years ago to present)
  • Rise of mammals, leading to grasslands.
  • Appearance of primates, cetaceans, birds, and flowering plants.
  • The Pleistocene epoch saw human evolution and megafauna extinction.

Documented and Unknown Species

• Approximately 1.2 million species have been described.
• Millions remain undiscovered.
• Biodiversity hotspots, like rainforests and coral reefs, house many undiscovered species.

Modern Extinction Rates

• Current rates are higher than background rates in the fossil record.
• Anthropogenic activities, are the principal drivers of accelerated rates.
• The Chinese Paddlefish was declared extinct in 2022.

Contrasting Eras: Past Versus Present

• Biodiversity experienced radiations and extinctions shaped by biological and environmental factors.
• Today's rapid decline is due to human activities, making it a unique period.
• Past biodiversity changes were influenced by volcanic eruptions etc..
• Today's loss is due to habitat destruction, pollution, climate change, overfishing, and invasive species.

Biodiversity Resilience and Recovery

• Historically, biodiversity recovery took millions of years.
• The current loss pace raises concerns about modern ecosystem resilience and recovery.

Significance of Understanding these Contrasts

• Human Impact Realisation: Grasping contrasts with historical data forces us to confront human impact.
• Guiding Conservation: Recognising the difference helps tailor conservation strategies.
• Predictive Insights: Scientists can better predict future shifts in biodiversity, aiding with conservation planning.

Broader Implications for Ecology and Evolution

• Ecological Niches: The continuous evolution influences ecological niches.
• Evolutionary Potential: Diverse genetic pools offer potential while rapid loss limits potential lineages.

Causes of Anthropogenic Species Extinction

• Humans play a role in reshaping Earth's biodiversity, pushing species to extinction.
• Understanding the causes of human activities is essential for sixth mass extinction.

Causes of Anthropogenic Species Extinctions

• Human-induced changes result in the decline or extinction of species.

Habitat Destruction

• Deforestation: Forests are cleared for agriculture, urbanisation at alarming rates.
• Deforestation removes direct habitats and fragments the remaining habitats.
• Examples: Amazon rainforest in Brazil and Bornean forests in Indonesia.

Wetland Draining

• Wetlands, essential for species, are drained for agriculture and construction.
• They play crucial roles in water purification and flood control.
• Examples: Florida Everglades in the USA and Mesopotamian Marshes in Iraq.

Pollution

• Water Pollution: Industrial waste, untreated sewage, and agricultural run-offs can lead to eutrophication.
• Oil spills have catastrophic impacts on marine ecosystems.
• Air Pollution: Industrial and vehicular emissions contribute to acid rain, harming freshwater systems and soils.
• Land Pollution: Improper waste disposal contaminates soil and groundwater.
• Pesticides and fertilizers contaminate soils, affecting plants and organisms,

Overexploitation

• Overhunting and Overfishing: Unsustainable practices lead to a decline in species.
  • Examples: The passenger pigeon was hunted to extinction.
• Pet Trade and Medicine: The capture, selling of species, threatens reptiles, birds, and mammals.
  • Rhino populations are threatened due to poaching for their horns.

Introduced Species

• Invasiveness: Introduced species can outcompete native species.
• Without natural predators, invasive species thrive and alter ecosystems.
  • Examples: Cane toads in Australia and grey squirrels in the UK.

Climate Change

• Temperature and Weather Patterns: Changes affect habitats and food availability.
• Melting Ice Caps: Cause polar species habitat loss.

Globalisation

• Spread of Diseases and Pests:
  • Increased movement introduces diseases or pests, decimating local species.

Case Studies: Extinct Species

• North Island Giant Moas
  • Dinornis novaezealandiae
  • Formerly native to North Island, New Zealand.
  • Weighed up to 250kg with a height of 3.6 meters.
• Reasons for Extinction
  • Overhunting: The Māori hunted the moa for food.
  • Habitat Destruction: Forest clearances diminished the habitat.

Caribbean Monk Seals

• Neomonachus tropicalis
• Formerly located throughout the Caribbean Sea.
• Had a diet mainly of fish and crustaceans
• Reason for extinction: Overhunting, habitat degradation, Reduced Prey Availability

Causes of Ecosystem Loss

• Human activities are the chief architect behind the increasing rate of ecosystem loss.
• Rapid population drives increasing rates of damage development and industrialization.

Habitat Destruction

• Deforestation: Millions of hectares of forests are cleared yearly.
• Deforestation leads to habitat loss and disrupts migratory routes and food sources.
• Drainage of Wetlands: The "kidneys of the Earth", play a pivotal role in water purification. Drainage leads to urban sprawl, resulting in dire ecological consequences.
• Infrastructure Development: Roads, bridges, dams, fragment natural habitats.

Pollution

• Water Pollution: Chemicals, waste, and other pollutants from agriculture pollute water bodies.
• Eutrophication, from excess nutrients, leads to reduced oxygen and the death of aquatic life.
• Air Pollution: Cause acid rain, affecting freshwater and terrestrial habitats.
• Soil Pollution: Heavy metals and pesticides severely harm the soil.

Overexploitation

• Overfishing disrupts marine ecosystems, leading to irreversible damage.
• Overhunting threatens terrestrial ecosystems.

Climate Change

• Rising temperatures and melting ice caps threaten coastal ecosystems.

Invasive Species

• Lead to changes in species' population, and overall decline in ecosystem.
• Land use loss is due to urbanization directly translates to habitat loss.

Southeast Asian Dipterocarp Forests

• Dipterocarp forests illustrate how anthropogenic factors lead to ecosystem degradation.
• Forests stretch across countries like Malaysia, Thailand, Indonesia, and boast species like the endangered rhino.
• Logging: Abundance of hardwood timber caused legal and illegal logging.
• Palm Oil Plantations skyrocketed the global palm oil demand.
• Slash-and-Burn Agriculture includes land burned to enrich soil temporarily.
• Consequences cause species to face the threat of extinction due to degraded habitats.

Evidence for a Biodiversity Crisis

• Evidence can be drawn from reports from intergovernmental sources.
• You need to understand that surveys need to be repeated to provide an accurate change rate.
• Peer reviewed published resources are needed.

The State of Biodiversity Reports

• These reports have become essential for environmental scientists, policymakers, and conservationists.

World Wildlife Fund (WWF) Living Planet Reports:

• These reports highlight the decline in biodiversity.
• There is an average decline of 60% in vertebrate species.
• The leading cause is the range from habitat degradation, overfishing, etc..

Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) Reports

• These assessments are undertaken by experts from various disciplines.
• of the 8 million estimated animal and plant species, up to 1 million face extinction.
• Direct observations of species is a huge decline.

Decline in Species Populations

• Direct observations across taxa is a reality:
• Indicators of environmental health for birds indicate decline.
• There has been in Europe for farmland birds, due to farming.
• Migratory bird loss and changing is altering migration.
• German insect biomass, that is a ecosystem function for pollination is declined.
• Roughly 25% of mammal species are flagged to be near extinction by The IUCN. -Habitats are significantly altered.

Degradation of Ecosystem Services

• Degradation is rendered to the main threat:
• Bee populations affecting crops.

Alteration in Ecological Interactions:

• Changing species disrupts ecosystems.
• apex predators effect population.
• Plants and pollinators at risk.

Climate Change Indicators:

• species move poleward.
• temperatures alter life cycle event
• corals expel leading to reduced capacity.

Pressures on Freshwater Ecosystems:

• habitats flora/fauna altered.

Causes of the current Biodivesity Crisis:

• The overall cause includes the spread of the human population.
• Hunting,poaching
• deforestation+overexploitation

In Situ Conservation

• Prioritizes conservation in natural habitats

OverExploitation

• Many fisheries have been depleted.
• Hunting/poaching,forests reduce the habitats.