Biogeography & Marine Realms Lecture Notes

A set of vocabulary flashcards covering the fundamental concepts, terminology, and historical/ecological case studies of marine biogeography as presented in the lecture.

Biogeography

An integrative field that explores the distribution of species, how they form distinct ecosystems, and their geographical limits by uniting concepts from ecology, evolutionary biology, genetics, geology, and physical geography.

Lystrosaurus

A Triassic therapsid whose fossil evidence is found in Africa, India, and Antarctica, supporting the theory that these continents were once joined.

Cynognathus

A Triassic therapsid approximately $3\,m$ long whose fossil remains are found in South America and Africa.

Mesosaurus

A freshwater reptile whose fossil remains are found in South America and Africa, indicating previous land connectivity.

Glossopteris

A fossil fern found in all southern continents, providing evidence that they were once joined in a single landmass.

Alfred Wallace

Considered the father of biogeography.

Historical Explanations

Biogeographic explanations that focus on past, large-scale geological or climatic events to understand why a taxon is confined to its present range.

Ecological Explanations

Biogeographic explanations that focus on current, small-scale factors such as hydrodynamics, reproduction behavior, and physiological tolerances.

Benthic Zone

The ecological region at the lowest level of a body of water, including the seafloor.

Pelagic Zone

The part of the open sea or ocean comprising the water column.

Bathyal Zone

The ocean depth zone ranging from approximately $1000\,m$ to $4000\,m$.

Abyssal Zone

The ocean depth zone ranging from approximately $4000\,m$ to $6000\,m$.

Hadal Zone

The deepest part of the ocean, ranging from approximately $6000\,m$ to $11000\,m$.

Plankton

Passive drifters on ocean currents, including large organisms like jellyfish.

Phytoplankton

Photosynthesizing plankton that serve as primary producers in the ocean.

Zooplankton

Animal-like heterotrophic plankton.

Nekton

Active swimmers in the water column, such as fish and marine mammals.

Meiobenthos

Benthic organisms, or meiofauna, that are less than approximately $1\,mm$ in length.

Microbenthos

Benthic organisms that are less than approximately $0.1\,mm$ in size.

Biome

A large collection of types of flora and fauna occupying a major habitat, such as a coral reef or tropical rainforest.

Biogeographic Realms

Very large areas where biotas are internally coherent at higher taxonomic levels due to a shared and unique evolutionary history.

Biogeographic Provinces

Regions with distinct biotas and degree of endemism at the species level, resulting from isolation by historical or geographical factors.

Marine Snow

Sinking organic material, such as phytodetritus and dead bodies, that provides food for deep-sea life.

Thermocline

The boundary between the upper mixed ocean zone and deeper water where temperature changes rapidly.

Halocline

A depth gradient in the ocean where salinity changes significantly.

Pressure Gradient

In the ocean, water pressure increases at a rate of $1\,atm$ for every $10\,m$ of depth.

Antarctic Circumpolar Current (ACC)

The world's largest current that thermally isolates Antarctica, keeping sea temperatures around $-2\,^{\circ}C$ and acting as a soft barrier to species dispersal.

Vicariance

The geographical separation of a population by a physical barrier, such as the closing of the Panama Isthmus, leading to allopatric speciation.

Messinian Crisis

An event approximately $5.5$ million years ago where the Mediterranean Sea dried up due to the closing of the Strait of Gibraltar.

Lessepsian Exchange

A faunal exchange between the Red Sea and the Mediterranean Sea following the opening of the Suez Canal.

Ship Ballast

A major invasion vector where cargo ships carry aquatic species in stability water, transforming marine ecosystems worldwide.