Biodiversity, Evolution, Taxonomy, and Conservation - Flashcards

Flashcards covering biodiversity concepts, spatial patterns, measurement, evolutionary history, taxonomy, systematics, and conservation topics from the provided notes.

What is biodiversity?

Variability among living organisms from all sources and the ecological complexes of which they are part; includes diversity within species, between species, and of ecosystems.

What are the major components of biodiversity by type?

Genetic diversity (variation in genetic makeup among individuals and populations); Organismal diversity (variation at a taxonomic level, e.g., species, genera); Ecological (ecosystem) diversity (differences between habitats and biomes).

What are alpha, beta, and gamma diversity?

Alpha diversity: diversity within a particular area or ecosystem; Beta diversity: differences in alpha diversity between ecosystems; Gamma diversity: overall diversity across ecosystems in a broad region.

What do species-area curves illustrate?

Larger areas tend to contain more species than smaller areas.

What is species richness?

The number of species within a given sampling area.

What is species evenness?

How abundant each species is relative to the total number of individuals.

What is the distinction between alpha, beta, and gamma diversity in simple terms?

Alpha is within-area diversity, beta is differences between areas, and gamma is regional total diversity.

Approximately how many described species are there and what is the uncertainty about total extant species?

About 1.5 million described species; total extant species are estimated from ~0.5 million to ~1 trillion, with most estimates around 10 million.

What percent of extant species are still undescribed?

Around 90%.

What are common extrapolation approaches for measuring biodiversity?

Canvassing experts; using patterns of species description; focusing on well-studied areas; using well-studied groups to estimate totals.

What are diversity indices and what do they account for?

Quantitative measures of diversity that account for both species richness and evenness (e.g., Shannon-Wiener Index, Simpson index).

What are key cautions when measuring biodiversity?

Extrapolation from small areas can introduce error; estimates and indices are based on samples; detection is uneven; serves as a baseline for conservation and monitoring.

What marks the Archean Eon in the Precambrian?

Low oxygen environment; formation of crust; first life around 3.8 billion years ago (chemoautotrophic prokaryotes); cyanobacteria begin photosynthesis.

What happened during the Great Oxygenation Event?

Around 2.5 billion to 570 million years ago; oxygenation of Earth’s atmosphere mainly through photosynthesis and some photodissociation, raising O2 levels.

When did eukaryotes arrive and what dominated life before the Cambrian explosion?

Eukaryotes arrived by about 2 billion years ago; life was dominated by small soft-bodied organisms until the Cambrian explosion.

What was the 'snowball Earth' period and its significance?

Cryogenic period from ~720 to 635 million years ago with widespread glaciation; led to environmental conditions that preceded the rise of more diverse life in the Ediacaran.

What is the Ediacaran period known for?

635–541 million years ago; proliferation of multicellular soft-bodied organisms.

When does the Phanerozoic eon begin and what are its major subdivisions?

Begins at 542 million years ago; includes the Paleozoic, Mesozoic, and Cenozoic eras.

What is the Cambrian explosion?

Major diversification of form and function; most major animal phyla appear, though marine life remains dominant.

What happened in the Ordovician period?

First vertebrates with true bones appear; shallow seas with abundant marine invertebrates.

What notable event occurred in the Silurian period?

First vascular plants with terminal eusporangia; major diversification of fish.

What occurred during the Devonian period?

Significant radiation on land; colonization by tetrapods and arthropods; mass extinction near the end of the period.

What characterized the Carboniferous period?

Warm, humid climate with extensive forests; generation of massive coal reserves; very high atmospheric oxygen (~35%); reptiles appear with amniotic eggs.

What happened in the Permian period?

Supercontinent Pangea; climate became drier; mass extinction at the end of the period; many marine biota died out; conifers become more dominant.

What are the key features of the Mesozoic era?

Known as the age of dinosaurs; Triassic (recovery, warm/dry), Jurassic (first birds, large dinosaurs), Cretaceous (high sea levels, angiosperms); ends with a mass extinction.

What marks the Cenozoic era in broad terms?

65.5 million years ago to present; Pleistocene (ice ages) followed by Holocene; the Anthropocene denotes significant human impact.

Name the major mass extinction events listed and approximate losses.

End Ordovician (~85%); Late Devonian (~80%); Permian (~95%); End-Triassic (~80%); Cretaceous-Paleogene (~75%); Holocene/Anthropocene (possible, due to human impact).

What general pattern does the fossil record show regarding biodiversity over time?

An erratic but relentless increase in biological diversity; not a neat progressive trend.

What is systematics?

The study of the diversity of organisms and their evolutionary relationships.

What is phylogeny?

The evolutionary history of a taxon.

What is a cladogram?

A simplified visualization of a taxon’s evolutionary history showing relationships.

What is a synapomorphy?

A newly derived character state shared by all members of a taxon.

What is a clade?

A group containing a common ancestor and all of its descendants (monophyletic group).

What is a monophyletic group?

A group that includes the most recent common ancestor and all of its descendants (a clade).

What is a paraphyletic group?

A group that includes the most recent common ancestor but not all of its descendants.

What is a polyphyletic group?

A group composed of taxa derived from more than one ancestor.

What is an outgroup in phylogenetics?

A reference taxon used to root a cladogram and infer evolutionary relationships.

What mnemonic helps remember the major taxonomic ranks, and what are the ranks?

'Odes King Philip Come over For good sour' representing Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

Who is known as the first taxonomist?

Aristotle.

Who introduced the binomial system of nomenclature?

Carolus Linnaeus.

What is a taxon?

A group of organisms at a particular level of a classification system.

How should genus and species names be formatted in writing?

Genus and species names should be italicized (or underlined); the specific epithet is not capitalized; the genus name precedes the epithet.

What is a holotype?

The specimen on which a species description is based.

What is a paratype?

A specimen collected at a different place or time than the holotype; a supplementary type specimen.

What is an isotype?

A specimen collected at the same place and time as the holotype (often used in taxonomy; notes sometimes spell it as ‘isotype’).

What is the significance of a type specimen?

It anchors the name of a species and serves as the reference for that species’ identity.

What is a non-native set of values in biodiversity conservation broadly categorized as?

Direct use values (consumption/production), indirect use values (ecosystem services), and non-use values (existence, bequest, option values).

Give examples of direct use values of biodiversity.

Food, medicines, biocontrol, industrial materials, recreational harvesting, ecotourism; examples include staple crops (corn, wheat, rice, soy, potatoes, sorghum) and farmed animals (chicken, goat, cow, sheep, pigs, horses).

Give examples of indirect use values of biodiversity.

Carbon sequestration, water purification, flood control, nutrient cycling, pollination, soil formation, and maintenance of food webs.

What are non-use values of biodiversity?

Option value (saved for future use), Bequest value (preserve for future generations), Existence value (value placed on living things regardless of use), and intrinsic value.

What is the precautionary principle in biodiversity conservation?

Biodiversity elements with potential use should not be lost simply because we do not yet know their value.

What is in situ conservation?

Conservation within natural habitats—protected areas, sustainable development, restoration of ecosystems, and control of invasive species.

What is ex situ conservation?

Conservation outside natural habitats—seed banks, zoos, culture collections, captive breeding, artificial propagation.

How is endemism distributed geographically?

Endemic species are found in restricted areas; endemism tends to peak on large oceanic islands and increases from poles to the equator.

What are biodiversity hotspots and their criteria?

Regions with high species richness and endemism; criteria include Irreplaceable (at least 1500 endemic vascular plants) and Threatened (loss of at least 70% of original habitat). They cover a small fraction of Earth’s land but host a large share of biodiversity (e.g., 45% of vascular plants and 35% of vertebrates).

What are some limitations of the hotspot approach?

Limited to well-known taxa, largely terrestrial, focuses on species richness, may miss other taxa and regions with conservation value, and cost predictions can be challenging.

What is endemism and how does it relate to conservation hotspots?

Endemism refers to species restricted to a particular area; hotspots prioritize areas with many endemic species and high threat to target conservation actions.