Fossil Record and Origin of Life

Layers of sedimentary rocks that hold fossils.

Determining fossil ages using strata; deeper means older.

Method using radioactive decay to find exact fossil ages.

Time taken for half of a parent isotope to decay.

Radiometric dating using carbon-12 and carbon-14 ratios.

Mutual relationship where one organism lives within another.

Earliest single-celled organisms contributing to Earth's atmosphere.

A theory that extreme glaciation confined life to warm areas.

An assemblage of larger, soft-bodied organisms that existed prior to the Cambrian period.

The sudden appearance of fossils resembling modern phyla during the Cambrian period, marking a rapid increase in diversity.

The process where plants and fungi moved to land around 475 million years ago, soon followed by arthropods.

The evolution of tetrapods from lobed-finned fishes, marking a significant evolutionary step.

A geological period characterized by high atmospheric oxygen levels and the existence of large anthropoids and coal forests.

Evolutionary change in the timing or rate of an organism's development, affecting body form.

Genes that dictate where body parts develop in an organism, crucial for body plan organization.

A specific type of homeotic gene that provides positional information in animals during development.

Structures that evolve for one purpose but are adapted for another function.

A group that includes a single ancestral species and all of its descendants, also called a clade.

One of the three domains of life, consisting of organisms with complex cells.

A diverse group of unicellular and multicellular eukaryotes, often classified under a single kingdom.

A group of protozoans that move using cilia and have complex nuclei.

A group that includes certain heterotrophs and algae with hairy and smooth flagella.

Unicellular algae with a silica cell wall, major phytoplankton component.

Unicellular or colonial algae with yellow-brown pigments; some are mixotrophic.

Filamentous decomposers or parasites, once thought to be fungi.

Organisms with porous, multi-chambered shells made of organic material and calcium carbonate.

Marine protists with delicate silica tests usually fused into one piece.

Supergroup that includes animals, fungi, and related protists, characterized by lobe-shaped pseudopodia.

A group of protists characterized by their unique cytoskeleton and includes diplomonads, parabasalids, and euglenozoans.

Protists with mitochondria called mitosomes, anaerobic energy, two nuclei, multiple flagella, often parasites.

Have reduced mitochondria called hydrogenosomes that generate energy anaerobically and use undulating membranes.

Diverse mixotrophic protists with a crystalline rod, includes predatory heterotrophs and photoautotrophs.

A group characterized by membrane-bound sacs called alveoli under the plasma membrane, includes dinoflagellates, apicomplexans, and ciliates.

Aquatic mixotrophs with two flagella and internal cellulose plates, known for toxic blooms and red tides.

Parasitic organisms with specialized organelles for penetrating hosts, involved in a complex life cycle.

The parasite causing malaria, which changes surface proteins and requires both mosquito and human hosts to complete its life cycle.

Asexual spores produced by ascomycetes fungi.

A phylum of fungi defined by the club-like structure called basidium.

Circles of mushrooms formed by mycelium spreading from a central point.

Fungi that form beneficial relationships with plants, algae, and animals.

Mutualistic relationship between fungi and plant roots.

Symbiotic association between a fungus and a photosynthetic organism.

A general term for fungal infection in animals.

Common fungal infections like athlete's foot and ringworm.

A group composed of some but not all members descending from a common ancestor.

A group that does not include its most common ancestor.

Similarity in structure across different species indicating common ancestry.

Changes over large time scales, such as the origin of photosynthesis.

Composed of water vapor, nitrogen, and carbon dioxide from volcanic eruptions.

Areas where organic molecules formed, thought to be early life origins.

An environment where oxidation is prevented, facilitating organic molecule formation.

Conducted experiments demonstrating abiotic synthesis of organic molecules.

Probable first genetic material on Earth was RNA.

RNA molecules capable of catalyzing chemical reactions.

DNA is more stable and replicates with fewer errors compared to RNA.

Documents of life's history and the first evidence of evolutionary change.

Rocks formed by the accumulation of sediments in layers known as strata.

The process of life developing from less complex to more complex forms.

The process where a parent isotope decays into a daughter isotope at a constant rate.

An isotope that is produced from the decay of a parent isotope.

The evolution that gave rise to plants, fungi, and animals from single-celled organisms.

Fossilized structures made of layers of cyanobacteria and sediment.

The theory that mitochondria and plastids originated from small prokaryotes living within larger cells.

A diverse clade that includes dinoflagellates, apicomplexans, and ciliates, originating from secondary symbiosis.

A subgroup of Euglenozoans with a single mitochondrion and a unique DNA mass called kinetoplast.

Fungi that form sheaths of hyphae over roots and into root cortex spaces.

Fungi that extend hyphae into root cells and form tubes.

Sexually signaling molecules used by fungi for mating communication.

The union of the cytoplasms of two parent mycelia.

A fungal mycelium with two or more haploid nuclei per cell.

Fusion of two haploid nuclei to form a diploid nucleus (zygote).

Aquatic fungi with flagellated spores; may be the most ancestral fungi lineage.

Mycelium reproduces sexually, forming basidiocarps that produce basidiospores.

Fungi form mutualistic relationships with plants, algae, cyanobacteria, and animals.