IndietroGeneral Biology: Evolution, Phylogeny, Prokaryotes, and Eukaryotes
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Termini in questo insieme (27)
Macroevolution refers to large-scale evolutionary changes that occur over long periods, leading to the formation of new species and higher taxonomic groups.
Abiotic synthesis is the formation of organic molecules from inorganic substances without biological activity, a key step in the origin of life.
The RNA world hypothesis proposes that early life was based on RNA molecules that both stored genetic information and catalyzed chemical reactions.
A protocell is a simple, pre-cellular structure with a membrane-like vesicle that exhibits some characteristics of living cells, such as maintaining an internal environment.
Radiometric dating estimates the age of fossils by measuring the decay of radioactive isotopes and their known half-lives.
Endosymbiosis is the theory that eukaryotic cells originated when a prokaryotic cell engulfed another, which then became an organelle like mitochondria or chloroplasts.
The Cambrian explosion was a rapid diversification of multicellular animal life about 540 million years ago, producing many major animal groups.
A mass extinction is a widespread and rapid decrease in biodiversity, eliminating many species in a relatively short geological time.
Adaptive radiation is the rapid evolution of many species from a common ancestor, often following mass extinctions or colonization of new habitats.
Heterochrony is an evolutionary change in the timing or rate of developmental events, affecting organism morphology.
Phylogeny is the evolutionary history and relationships among species or groups of organisms.
Homology refers to traits inherited from a common ancestor, while analogy refers to similar traits evolved independently by convergent evolution.
A clade is a group of organisms that includes an ancestor and all its descendants, representing a single branch on the tree of life.
Maximum parsimony is a principle that favors the phylogenetic tree requiring the fewest evolutionary changes.
Prokaryotes are unicellular organisms without a nucleus, including bacteria and archaea.
Gram-positive bacteria have thick peptidoglycan cell walls and stain purple; Gram-negative bacteria have thin walls and an outer membrane, staining pink and often more antibiotic-resistant.
An endospore is a resistant, dormant structure formed by some bacteria to survive harsh conditions.
Binary fission is the asexual reproduction process in prokaryotes where one cell divides into two genetically identical cells.
Horizontal gene transfer is the movement of genetic material between organisms other than by descent, increasing genetic diversity in prokaryotes.
Obligate aerobes require oxygen; obligate anaerobes are poisoned by oxygen; facultative anaerobes can survive with or without oxygen.
Evidence includes mitochondria and chloroplasts having double membranes, their own DNA, and similarities to prokaryotic cells.
The major eukaryotic supergroups are Excavata, SAR, Archaeplastida, and Amorpheans.
Secondary endosymbiosis occurs when a eukaryotic cell engulfs another eukaryotic cell that already contains a plastid.
Diatoms have silica cell walls and contribute to carbon storage by fixing CO₂ in aquatic ecosystems.
Dinoflagellates move using two flagella; some cause harmful algal blooms called red tides.
Plasmodial slime molds form a multinucleate mass, while cellular slime molds aggregate individual cells during part of their life cycle.
Mutualism benefits both species, commensalism benefits one without harming the other, and parasitism benefits one at the expense of the other.