Lecture 13 – What Ecology is and Why it Matters

Vocabulary practice flashcards covering fundamental concepts from Lecture 13: definitions of ecology, systems thinking, endosymbiosis, biological scales, range limits, and mass extinction.

Ecology

The science of how organisms interact with each other and with their environment, the distribution and abundance of species, and the structure and function of ecosystems (also described as the science of biodiversity).

Oikos

The Greek root of the word ecology, meaning "home" and "place to live."

Dobzhansky's Dictum on Ecology

The principle expressed by Theodosius Dobzhansky: "Nothing in biology makes sense except in the light of evolution, and nothing in evolution makes sense except in the light of ecology."

"The Ecological Theatre and the Evolutionary Play"

A 1965 book title by G. Evelyn Hutchinson conveying that ecology serves as the backdrop or setting where evolution occurs, with organism-environment interactions giving rise to natural selection.

Systems Thinking

An ecological approach that views biological systems as dynamic and complex networks with emergent properties arising from interactions among component parts, rather than reducing them to isolated pieces.

Endosymbiotic Theory

Lynn Margulis's theory proposing that mitochondria originated when larger prokaryotes engulfed smaller prokaryotes and assimilated them into their cellular structure, supported by mitochondria having their own bacterial-like genomes.

Symbiosis

An ecological relationship where two different species live in close association with one another.

Mutualism

A specific symbiotic interaction where both participating species derive a fitness benefit from the relationship.

"Devil's Garden"

A patch in the Amazon rainforest established almost entirely by a single tree species, Duroia hirsuta, which is created when mutualistic ants kill the saplings of non-host trees to protect their nesting sites.

Global Eukaryotic Species Diversity

An extrapolated estimate indicating approximately $8.7\text{ million}$ eukaryotic species inhabit Earth, with more than $85\%$ currently remaining unknown to science.

Tree of Life Biodiversity Distribution

The unequal phylogenetic distribution of Earth's species, wherein bacteria represent the vast majority of all biological diversity ($70\text{--}90\%$ of all species).

Model Species

Representative laboratory organisms used to study broader taxonomic groups: Mus musculus (representing all vertebrates), Drosophila melanogaster (representing all invertebrates), and Arabidopsis thaliana (representing all plants).

Population

All individuals belonging to the same species living together in a specific geographic place at a particular time (e.g., all zebras in a savanna).

Ecological Community

All populations of different species coexisting in the same geographic place at a specific time (e.g., all zebras, giraffes, elephants, plants, and insects in a savanna).

Ecosystem

The combined biological community of all living species together with the non-living (abiotic) physical environment.

Mountain Lion (Puma concolor) Geographic Range

An example of a species with a wide geographic distribution, extending across large expanses of western North America and South America.

American Pika (Ochotona princeps)

A small alpine rabbit relative that acts as an extreme habitat specialist, restricted to isolated alpine rock piles and highly vulnerable to extinction from climate change.

Layered Filtering Model

A conceptual framework demonstrating how the composition of species within a community is determined sequentially through dispersal constraints, abiotic conditions, and species interactions.

Abiotic Conditions

Non-living environmental factors limiting species ranges, partitioned into inexhaustible conditions (such as climate, temperature, moisture, and salinity) and exhaustible resources (such as food, nutrients, and space).

Species Abundance

The number of individuals of a given species present within a specified geographical area.

Lonesome George

The famous last surviving individual of a Galápagos tortoise subspecies who died in 2012, marking the complete extinction of that taxon.

Malthusian Population Theory

Thomas Malthus's proposition that populations cannot grow faster than the growth rate of their resources, leading to a carrying capacity and a "point of crisis" that informed Darwin's struggle for existence.

The Sixth Extinction

The ongoing mass extinction driven by human activities, evidenced by population or range declines in $32\%$ of known vertebrate species ($8,851 / 27,600$) and a $29\%$ decline in North American bird abundance since 1970.