Species Concepts and Ecosystems

Species Concepts: Defining Species

• Several concepts define species, not a single definition

• Biological Species Concept: Organisms are the same species if they can interbreed and produce fertile offspring. Lions are the same species, but a lion and a tiger hybrid (liger) is infertile, so they are separate species. Difficult to apply to asexual or extinct organisms.

• Morphological Species Concept: Organisms share identical physical features. Useful for asexual or extinct organisms. Can be problematic because different species may look similar.

• Ecological Species Concept: Organisms occupy the same ecological niche. More similar organisms are more likely to occupy the same niche, but even if similar, species do not completely overlap, with subtle niche differences preventing overlap.

Ecosystems and Niches

• Ecosystem: An interacting system of living and non-living entities in a defined area. The community of organisms and their environment
• Biodiversity: Variety of ecosystems, habitats, species, and genotypes in a specific area.
• Niche: A species' role in an ecosystem. Includes nutrition, food web position, habitat interaction, and effects on other organisms.

Biodiversity Assessment

• Species richness: Number of different species in an area. Higher richness implies higher biodiversity.
• Distribution and abundance: Quantifying species locations and numbers. Sampling often used.
• Random sampling techniques: Crucial for unbiased biodiversity measurements (e.g., using random coordinates from an app).

Measuring Biodiversity: Sampling Techniques

• Line transects: Measure species abundance along a designated line (e.g., beach edge to top). Quadrats placed at set intervals along the line.
• Belt transects: Measure species abundance at every point along the line. Quadrats placed in succession or by recording touching organisms.

Extinction

• Mass extinctions: Periods with large numbers of species disappearing. Dinosaurs' extinction around 66 million years ago is an example.
• Causes of extinction: Climate change, competition, habitat loss, human activity.

Maintaining Biodiversity: Reasons and Threats

• Stability of ecosystems: Loss of species impacts ecosystem health.
• Benefits to humans: Biodiversity provides resources & economic advantages (e.g., medicines, tourism).
• Threats to biodiversity: Human activities are major drivers.
  • Greenhouse gases: Increased global warming from fossil fuels.
  • Human population growth: Increased resource demand leads to habitat loss.
  • Pollution: Heavy metals, acidic gases, phosphates reduce species' chances of survival.
  • Invasive species: Introduced organisms that potentially threaten native species through competition, predation, or habitat change (e.g., possums in New Zealand).

Conservation Tools and Methods

• Botanic gardens: Plant conservation centers similar to zoos, involved in breeding, reintroduction, education, and research.
• "Frozen zoos" / Cryopreservation: Preserving embryos, sperm, eggs, and tissue samples in liquid nitrogen for future use. Maintains genetic diversity.
• Seed banks: Storing seeds for long-term plant conservation. The Royal Botanic Gardens at Kew and a permafrost seed bank are examples.
• Assisted reproduction (e.g., IVF): Speeding up animal reproduction in zoos to increase populations. IVF is in vitro fertilization, using frozen samples for genetic diversity and ease of transportation.

This quiz explores various species concepts including the Biological, Morphological, and Ecological Species Concepts. It also delves into the definition of ecosystems and the importance of ecological niches in understanding species interactions. Test your knowledge on these fundamental topics in biology.