Life Science: Origin of Life and Characteristics of Living Things

Comprehensive vocabulary flashcards reviewing the origin of life theories, historical milestones, and fundamental characteristics of living organisms based on the lecture notes.

Life Science

The branch of science that studies living organisms and life processes—how living things are structured, how they function, how they grow and reproduce, how they interact with their environment, and how they have changed over time.

Estimated Age of Earth

Scientifically estimated to be over $4.5\text{ billion years}$ old.

Zircon Crystal

The oldest material found on Earth, estimated to be $4.3\text{ billion years}$ old; a naturally occurring mineral found in igneous, metamorphic, and sedimentary rocks that is highly resistant to weathering.

Early Earth Conditions

Geologically violent conditions during the planet's earliest history marked by continuous meteorite bombardment prior to surface cooling and solidification.

Ga (Gigaannum)

A unit of geological time equal to one billion years, used to reference when initial life originated on Earth around $3.8\,\text{Ga}$.

Prokaryotes (Origin Timeline)

Single-celled organisms that marked the initial beginning of life on Earth approximately $3.8\,\text{Ga}$ ago.

Multicellular Life Timeline

Complex cellular life that evolved over a billion years after the emergence of single-celled prokaryotes.

Arthropods

Invertebrates with jointed legs that comprise about $75\%$ of all animal species on Earth, serving crucial ecological functions as pollinators, nutrient recyclers, scavengers, and prey.

Homo sapiens Timeline

Modern human species believed to have evolved approximately $200\,000\text{ years ago}$.

Theory of Catastrophism

The theory proposing that Earth's landscape and life-forms have been shaped by sudden, short-lived, major events, formulated as a modification of the biblical creation story.

Georges Cuvier and Alcide Dessalines d'Orbigny

French scientists who supported the Theory of Catastrophism.

Catastrophic Succession of Life

The tenet of Catastrophism stating that following sudden global upheavals, each subsequent creation consisted of new life-forms that differed from prior ones.

Theory of Abiogenesis

The hypothesized starting point for all known life on Earth explaining how chemistry gave rise to biology without invoking supernatural causes or pre-existing organisms.

Spontaneous Generation Theory

The historical concept under abiogenesis proposing that living things were naturally generated from non-living matter.

Stanley Miller's Experiment (1953)

A laboratory simulation demonstrating that passing an electric spark (simulating lightning) through simple organic gases (simulating the early atmosphere) yielded amino acids.

Amino Acids

Organic chemical compounds formed during Miller's 1953 experiment, recognized as the building blocks of proteins and living tissues.

Theory of Biogenesis

The scientific principle stating that living organisms arise exclusively from pre-existing living organisms ('Life comes from pre-existing life').

Francesco Redi and Louis Pasteur

Prominent historical scientists whose experiments successfully disproved the idea of spontaneous generation.

Swan-Neck Flask

An S-shaped flask used in Louis Pasteur's experiment that permitted air circulation while preventing airborne microorganisms from reaching the boiled broth.

Pasteur's Flask Tilting Step

The action of tilting the swan-neck flask, allowing broth to contact microorganisms trapped in the neck curves and demonstrating subsequent microbial growth.

Historical Supporters of Biogenic Inquiries

Notable thinkers referenced in historical connection to spontaneous generation debates, including Descartes, Galileo, and Jan Baptista van Helmont.

Cell

The basic structural and functional unit of life that composes all living organisms.

Robert Hooke

The historical scientist credited with the discovery of the cell.

Matthias Schleiden

The scientist who contributed to cell theory by establishing that all plants are composed of cells.

Theodore Schwann

The scientist who contributed to cell theory by establishing that all animals are composed of cells.

Rudolf Virchow

The scientist who advanced cell theory by concluding that all cells arise from pre-existing cells.

Prokaryotes

Single-celled living organisms lacking a membrane-bound nucleus.

Eukaryotes

Organisms characterized in the lecture comparative chart as multicellular life forms.

Metabolism

The totality of chemical reactions carried out by an organism to obtain, transform, and use energy from nutrients, and to manage waste products.

Metabole

The Greek root word for metabolism, meaning 'change'.

Anabolism

The constructive metabolic phase characterized as a 'building up process'.

Catabolism

The destructive metabolic phase characterized as a 'breaking down process'.

Growth

The characteristic of living organisms involving an increase in physical size and an increase in total cell quantity.

Development

The physiological transformation throughout an organism's life cycle toward becoming more mature and structurally complex.

Life Span

The average duration of time an organism can live, such as $60\text{--}70\text{ years}$ for humans and $100\text{ years}$ for Narra trees.

Stimulus

Any environmental signal or change (e.g., light, temperature, sound, touch, or chemicals) that evokes a reaction or response in an organism.

Homeostasis

A self-regulating internal balancing mechanism by which an organism maintains internal stability amidst shifting external environmental conditions.

Organismal Interactions

Ecological relationships among living things—including competition, cooperation, predation, and symbiosis—that maintain ecological equilibrium.

Symbiosis

An ecological relationship between organisms of different species, categorized into mutualism, commensalism, and parasitism.

Mutualism

A symbiotic relationship where both involved species derive mutual benefits, exemplified by humans and gut bacteria.

Commensalism

A symbiotic relationship where one organism benefits while the other remains completely unaffected, such as cattle egrets and cattle.

Parasitism

A symbiotic relationship where one organism benefits while the host organism is actively harmed, such as ticks on dogs.

Reproduction

The biological capability of living organisms to produce offspring of their own kind, ensuring species continuity.

Sexual Reproduction

A form of reproduction requiring two parents that involves the fusion of specialized gametes through fertilization to generate genetically unique offspring.

Gametes

Specialized haploid reproductive cells (sperm and egg in animals; pollen and ovules in plants) that unite to form a zygote.

Zygote

The diploid single cell produced by the successful fertilization and fusion of male and female gametes.

Asexual Reproduction

A reproductive mode requiring a single parent, involving mitotic cell division without gamete fusion, producing identical genetic clones.

Budding

An asexual reproduction method where a new individual develops directly as an outgrowth or miniature replica from the parent organism, as observed in Hydra.

Binary Fission

An asexual reproductive method commonly occurring in unicellular organisms where a single cell splits into two identical daughter cells.

Levels of Biological Organization

The hierarchical structural organization in multicellular organisms: cells $\rightarrow$ tissues $\rightarrow$ organs $\rightarrow$ organ systems $\rightarrow$ organism.