Introduction to Biocomplexity and the Evolution of Life

A comprehensive set of vocabulary flashcards covering biocomplexity, ecosystem functions, biological thermodynamics, geologic dating methods, speciation theories, and the evolution of prokaryotic and eukaryotic life.

Biocomplexity

The study of life (Bios = life) and the complex interactions and characteristics shared by living organisms.

Cellular organisation

A characteristic where all organisms have $1$ or more cells, each bound by a membrane and capable of carrying out basic activities for living.

Heritable information

The passing of heredity information ($DNA$/$RNA$) from all organisms to the next generation.

Order

The precise, predictable internal structures followed by living things rather than being random.

Sexual reproduction

A process involving two parent organisms combining specialized sex cells, or gametes, to create genetically unique offspring via meiosis.

Asexual reproduction

A process requiring only one parent that relies on regular cell division, or mitosis, to create genetic clones.

Phototrophs

Organisms that obtain energy from sunlight, converting it into $ATP$ through photosynthesis or similar light-capturing processes.

Chemotrophs

Organisms that obtain energy by breaking down chemical bonds through redox reactions of organic or inorganic molecules.

Homeostasis

The maintenance of somewhat constant internal conditions, such as blood sugar control, body temperature regulation, and water balance.

Biotic environment

Living components of an environment, including predation, competition, and symbiosis.

Abiotic environment

Non-living components of an environment, such as light, temperature, water, wind, and mineral nutrients.

Provisioning services

Ecosystem services that provide essential goods like food, shelter, water, pharmaceuticals, and energy.

Regulating services

Ecosystem services such as climate regulation, carbon sequestration, and crop pollination.

Supporting services

Ecosystem services that include soil formation and primary production.

Nuclear fusion

The process in the sun's core where intense heat and pressure crush hydrogen atoms together to form helium, releasing light and heat.

Deep-sea hydrothermal vents

Hot springs on the ocean floor releasing mineral-rich water heated by magma, driving ecosystems through chemosynthesis.

Autotrophs

Self-feeders that produce complex organic molecules using carbon from simple substances like $CO_2$ and energy from light or inorganic reactions.

Heterotrophs

Other-feeders that cannot produce their own food and must take nutrition from plant or animal matter.

Detritivore

Decomposers like snails and worms that ingest and digest dead organic matter (detritus).

Saprophytes

Decomposers like fungi and bacteria that perform external digestion via enzyme secretion.

Zeroth Law of Thermodynamics

Defines temperature by stating that two systems in thermal equilibrium with a third system are in equilibrium with each other.

First Law of Thermodynamics

Energy cannot be created or destroyed, only changed in form or transferred.

Second Law of Thermodynamics

The total entropy (disorder) of an isolated system always increases over time, and heat flows naturally from hot to cold.

Third Law of Thermodynamics

As temperature approaches absolute zero, a system's entropy approaches a minimum constant value.

$10\%$ energy rule

The principle describing the inefficiency of energy transfer through trophic levels in a food web.

Trophic cascade

A process triggered by adding predators that reduces prey numbers and alters animal behavior, helping plants and other wildlife recover.

Radioisotopic dating

A scientific method used to find the age of rocks and fossils by measuring the decay of unstable radioactive parent atoms into stable daughter atoms.

Half-life ($T_{1/2}$)

The time taken for half of a sample of radioisotopes to decay to a stable form.

Uranium-238

A radioisotope with a half-life of $4.54$ billion years used to date the Earth.

Potassium-40

A radioisotope with a half-life of about $1.26$ billion years used to date ancient rocks and the era of the first bacteria.

Carbon-14

A radioisotope with a half-life of $5730$ years, useful for dating fossils of recent living organisms up to $60,000$ years old.

Stratigraphy

The branch of geology that studies rock layers (strata) to learn the history of the Earth and the order of past events.

Magnetostratigraphy

A method to estimate the age of a fossil site by measuring iron-bearing minerals that locked in the orientation of Earth's magnetic field when the rock formed.

Banded iron formations

Geochemical evidence from $1.8$ billion years ago ($BYA$) indicating the presence of insoluble iron oxides ($Fe_2O_3$) formed by early photosynthetic bacteria.

Primary endosymbiosis

An event where one organism lives inside another, leading to the evolution of eukaryotic cells with nuclei and membrane-bound organelles.

Adaptive radiation

An event that allows one or more lineages to greatly increase diversity over a relatively short time.

Natural selection

The process where the environment selects for heritable variations that confer an advantage, leading to higher reproduction and speciation.

Biological species concept

Defines a species as a group of actually or potentially interbreeding organisms that are reproductively isolated from other groups.

Morphological species concept

Identifies species as morphologically distinct or discrete based on specific physical characteristics.

Evolutionary species concept

Defines a species as a single lineage of ancestor-descendant populations that maintains its identity and has its own evolutionary tendencies.

Phylogenetic species concept

Identifies species on the basis of shared traits and RNA/DNA sequencing.

Homology

Characteristics of two species that are inherited from a common ancestor, such as the pentadactyl limb.

Analogy

Similar characteristic features of two species that are not inherited from a common ancestor, like wings in birds and insects.

Convergent evolution

The development of similar traits in different species due to common selection pressures rather than a common ancestor.

Taxonomy

The science of classifying organisms into groups based on shared traits.

Primordial soup

The theory that simple chemicals in early oceans were bound into amino acids and sugars by energy from lightning or the sun.

Miller-Urey Test

An experiment that proved the primordial soup theory by creating amino acids from simulated atmospheric gases and electric sparks.

LUCA

The Last Universal Common Ancestor, a unicellular organism with a lipid membrane that used $DNA$, $RNA$, and proteins.

Nitrogen fixation

The process where bacteria use the enzyme nitrogenase to convert inert atmospheric nitrogen gas ($N_2$) into biologically available ammonia ($NH_3$).

Syntrophy

A symbiotic metabolic partnership where bacteria break down molecules to release hydrogen for methanogenic archaea.

Binary fission

An asexual reproduction process where a cell grows larger until it splits into two genetically identical cells.

Conjugation

A form of horizontal gene transfer where a bacterial cell attaches to a recipient via a pilus to transfer $DNA$.

Transformation

The horizontal gene transfer process where competent bacteria absorb loose $DNA$ fragments from the environment.

Transduction

The accidental transfer of bacterial $DNA$ from one cell to another by a virus or bacteriophage.

Cyanobacteria

Photoautotrophs responsible for creating Earth's oxygen-rich atmosphere through oxygenic photosynthesis.

Methanogens

Specialized microorganisms in the domain Archaea that generate energy in oxygen-free environments, playing a vital role in carbon cycling.

Quorum Sensing

A social behavior in bacteria like Bacillus subtilis where cells release peptide signals to measure population size and coordinate group behavior.

Wolf-pack hunting

A cooperative behavior in Myxococcus xanthus where swarms glide over and destroy prey using lytic secretions.

Excavata

A supergroup of single-celled eukaryotes often featuring an asymmetrical shape and a feeding groove.

SAR Clade

A eukaryotic supergroup comprising Stramenopiles, Alveolates, and Rhizarians.

Archaeplastida

A supergroup containing red algae, green algae, and land plants, originating from the endosymbiosis of a cyanobacterium.

Unikonta

A eukaryotic supergroup including animals, fungi, and amoebozoans, typically characterized by cells with a single flagellum.

Choanoflagellate

A free-living, single-celled or colonial protist that is the closest living relative to animals.

Choanocyte

A specialized collar cell found inside the bodies of sponges.