Evolution, Speciation, and Biodiversity: Core Concepts in General Biology

Evolutionary Fitness and Selection

Definitions and Types of Fitness

Fitness in evolutionary biology refers to an organism's ability to survive and reproduce, passing its genes to the next generation. Several types of fitness and selection mechanisms are important for understanding evolution.

• Absolute fitness: The total number of offspring an individual produces that survive. Also called viability or fecundity.

• Relative fitness: The fitness of an individual compared to the highest fitness in the population, ranging from 0 to 1.

• Seksuele selectie (Sexual selection): Selection based on traits that increase mating success.

• Interseksuele selectie (Intersexual selection): Selection where females choose attractive males.

• Intraseksuele selectie (Intrasexual selection): Competition among males for access to females.

• Ornamenten (Ornaments): Traits that increase attractiveness and mating success, such as bright plumage or elaborate displays.

• Dimorfisme (Dimorphism): Differences between males and females in appearance due to sexual selection.

• Spermacompetitie (Sperm competition): Competition between males' sperm to fertilize eggs.

• Handicap hypothese (Handicap hypothesis): The idea that only the fittest males can afford costly ornaments.

• Sexy son hypothese (Sexy son hypothesis): Females prefer males with traits that will make their sons attractive to future mates.

• Monogamie (Monogamy): One male mates with one female.

• Polygynie (Polygyny): One male mates with multiple females.

• Altruïsme (Altruism): Behavior that benefits others at a cost to oneself, often explained by kin selection.

• Hamilton's rule: $rB > C$, where r is relatedness, B is benefit to recipient, C is cost to actor.

• Indirecte fitness (Indirect fitness): Fitness gained by helping relatives reproduce.

• Parent-offspring conflict: Differences in investment between parents and offspring.

Speciation and Reproductive Isolation

Mechanisms and Types of Speciation

Speciation is the process by which new species arise. It often involves reproductive isolation, preventing gene flow between populations.

• Soortvorming (Speciation): The origin of species, as described by Darwin's "Mystery of Mysteries."

• Micro-evolutie (Microevolution): Changes in allele frequencies within populations.

• Macro-evolutie (Macroevolution): Large-scale evolutionary patterns, such as the origin of new taxa.

• Biologisch soortconcept (Biological species concept): Species are groups of interbreeding natural populations that are reproductively isolated from other such groups.

• Reproductieve isolatie (Reproductive isolation): Barriers that prevent populations from interbreeding.

• Morfologisch soortconcept (Morphological species concept): Species are defined by structural features.

• Ecologisch soortconcept (Ecological species concept): Species are defined by their ecological niche.

• Fylogenetisch soortconcept (Phylogenetic species concept): Species are the smallest group sharing a unique genetic history.

• Allopatrische soortvorming (Allopatric speciation): Speciation occurs when populations are geographically separated.

• Sympatrische soortvorming (Sympatric speciation): Speciation occurs without geographic separation, often due to habitat or behavioral differences.

• Habitat isolatie (Habitat isolation): Populations live in different habitats and do not meet.

• Temporale isolatie (Temporal isolation): Populations breed at different times.

Prezygotic and Postzygotic Barriers

Barriers to reproduction can occur before or after fertilization.

• Prezygotische barrières (Prezygotic barriers): Prevent mating or fertilization between species.

• Postzygotische barrières (Postzygotic barriers): Prevent hybrid offspring from developing into viable, fertile adults.

• Verminderde hybride levensvatbaarheid (Reduced hybrid viability): Hybrids fail to develop or are frail.

• Verminderde hybride vruchtbaarheid (Reduced hybrid fertility): Hybrids are sterile.

• Hybride zone (Hybrid zone): Regions where different species meet and produce hybrids.

• Polyploïdie (Polyploidy): Speciation due to chromosome duplication, common in plants.

Phylogeny and Classification

Understanding Evolutionary Relationships

Phylogeny is the study of evolutionary relationships among species, often represented as trees.

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

• Taxon: A named group of organisms (e.g., species, genus, family).

• Node (Knoop): The point in a phylogenetic tree where a lineage splits.

• Branch (Tak): Represents evolutionary lineages.

• LUCA: Last Universal Common Ancestor of all living organisms.

• MRCA: Most Recent Common Ancestor of a specific group.

• Monofyletische groep (Monophyletic group): Includes an ancestor and all its descendants.

• Parafyletische groep (Paraphyletic group): Includes an ancestor and some, but not all, descendants.

• Polyfyletische groep (Polyphyletic group): Includes species with different ancestors.

Group Type	Definition	Example
Monophyletic	Ancestor and all descendants
Paraphyletic	Ancestor and some descendants
Polyphyletic	Species with different ancestors

Biodiversity and Ecosystem Diversity

Levels and Importance of Biodiversity

Biodiversity refers to the variety of life at different levels, from genes to ecosystems. It is crucial for ecosystem stability and human well-being.

• Genetische diversiteit (Genetic diversity): Variation in genes within a species.

• Soortendiversiteit (Species diversity): Number of species in an ecosystem.

• Ecosysteemdiversiteit (Ecosystem diversity): Variety of ecosystems in a biosphere.

Types of Diversity

• α-diversiteit (Alpha diversity): Diversity within a single habitat.

• β-diversiteit (Beta diversity): Difference in diversity between habitats.

Origin of Life and Major Evolutionary Events

Timeline and Key Concepts

The origin of life and major evolutionary transitions are central to understanding biological diversity.

• Metabolism first: Life began with networks of chemical reactions.

• Hadean, Archaean, Proterozoic, Phanerozoic: Geological eons marking major events in Earth's history.

• GOE (Great Oxidation Event): Rise of atmospheric oxygen due to photosynthesis.

• Multicellular organisms: Emergence of complex life forms.

Human Impact and Conservation

Anthropocene and Ecosystem Services

Humans have a significant impact on biodiversity and ecosystem functioning, especially in the current era known as the Anthropocene.

• Anthropoceen (Anthropocene): The era of significant human impact on Earth.

• Ecosysteemdiensten (Ecosystem services): Benefits humans receive from ecosystems, such as food, water, and climate regulation.

Key Terms and Concepts Table

Term	Definition
Viability	Ability to survive to reproductive age
Fecundity	Ability to produce offspring
Kin selection	Selection favoring traits that benefit relatives
Sympatric speciation	Speciation without geographic separation
Allopatric speciation	Speciation due to geographic isolation

Example: The evolution of Darwin's finches in the Galápagos Islands is a classic example of adaptive radiation and speciation due to geographic isolation.

Additional info: Some definitions and examples have been expanded for clarity and completeness based on standard biology textbooks.