Bio 205: Biodiversity and Species Concepts

3 Types of Biodiversity

Genetic, Species, Ecosystem

Genetic Biodiversity

Variety of genes and traits available within a species

Species Diversity

Variety of species within an ecosystem

Ecosystem Diversity

Variety of ecosystem and habitat types in an area of land and water

Observation Bias

Can’t find all possible species due to weather, seasons, etc. You just won’t be able to see/find everything.

Eukaryotes

Plants, Animals, Fungi

Prokaryotes

Bacteria and Archaea

Karl von Linne OR Carl Linnaeus

Colonialist explorer - Father of Taxonomy - Creator of Binomial Nomenclature

Taxonomy

the science of naming, describing, and classifying organisms into a structured, hierarchical system based on shared characteristics and evolutionary relationships

Platonic Ideal

Idea that there is a perfect version of each thing out there. Plato’s allegory of the cave.

Intraspecific

Within the same species

Interspecific

Amidst different species

Ring Species

groups of species with no clear boundary species to species so they can’t be defined easily

Holotype

The representative specimen for all future comparisons. Used as a platonic ideal (could be living or fossilized); kept in a Museum

Rarefaction Curve

a statistical graph that plots the number of observed species (or genetic units) on the y-axis against the number of sampled individuals, sequences, or plot units on the x-axis

Genetic Variation

Variation of genes within a species

Binomial Nomenclature

the Latin naming method - genus species

Species Concepts

the rulebook biologists use to draw lines between different groups of organisms.

Biological Species Concept

Must be able to reproduce sexually - viable offspring - reproductive isolation

PROS of Biological Species Concept

Directly links species identity to the primary mechanism of divergence (speciation via reproductive isolation). Good for studying population genetics, microevolution, and gene flow barriers in real time.

CONS of Biological Species Concept

Doesn’t apply to unicellular or asexual organisms. Or to extinct fossil lineages and organisms that routinely hybridize.

Phylogenetic Species Concept

Group of individuals with the most recent common ancestor

PROS of Phylogenetic Species Concept

Provides clear, quantifiable boundaries using molecular sequence data and clade structure (monophyly). Fully applicable to extinct organisms and asexual taxa.

CONS of Phylogenetic Species Concept

Not all species have the diverging pattern. With hybridization it is hard to identify the recent ancestor. All species cannot be monophyletic - introgression - parallel speciation

Hybridization

the act of combining (2 isolated populations)

Introgression

2 isolated populations start breeding into one another

Horizontal Gene Transfer

When a piece of a genome came from somewhere else

Conspecific

Same Species

Parallel Species

Branches of species - common ancestor (speciation)

Genetypic Cluster Species Concept

Clusters of genetically similar/same species. Separated by genetic gaps

PROS of Genetypic Cluster Species Concept

Ideal for high-throughput genomic data; allows researchers to define species boundaries using statistical clustering without needing prior knowledge of mating behavior or deep ancestry

CONS of Genetypic Cluster Species Concept

Clusters might interbreed - Arbitrary cutoffs must be set to determine where one "cluster" ends and another begins

Lineage-Based Concept

Ancestor based in 1 location (similar to PSC and Evolutionary Concept)

CONS of Lineage-Based Concept

It’s not defining species but population instead

Cohesion Concept

Similar to all the other Species Concepts

Evolutionary Species Concept

species as single, cohesive lineages of ancestor-descendant populations that maintain their distinct identity from other lineages through time and space

PROS of Evolutionary Species Concept

Extremely broad and inclusive; applies across deep time (fossil record), to both sexual and asexual organisms, and accommodates diverse evolutionary trajectories.

CONS of Evolutionary Species Concept

Highly abstract and hard to operationalize empirically, as determining what constitutes a "cohesive lineage" over long time scales requires subjective criteria.

Microevolutionary Researchers

They focus on short time scales and population genetics and overuse the Biological Species Concept because they directly study the mechanisms of reproductive isolation and gene flow.

Macroevolutionary Researches

They focus on deep time, extinction, and broad clade patterns and rely far more on Evolutionary and Phylogenetic concepts because reproductive isolation cannot be directly tested in fossils or ancient lineages

Biological Species Concept is more used by…

Evolutionary Biologists, Geneticists, Behavioral Ecologists because their goal is understanding how organisms diverge. - Process-oriented

Evolutionary/Phylogenetic concepts are used more in…

Systematics, Taxonomy, Phylogenetics, and Palaeobiology because their goal is classifying, identifying, and mapping historical relationships - Pattern-oriented

What is the role of museums in biology?

Museums act as essential biological repositories that preserve physical evidence of life on Earth to support research, education, and conservation. They house all Holotypes.