Diversity and Origin of Life on Earth

Flashcards covering the diversity and origin of life on Earth, including phylogenetic trees, biological classification, early life history, and major groups of organisms like microbes, plants, and animals based on lecture notes.

Phylogenetic tree

A diagram that shows the evolutionary history and relatedness of different organisms using anatomical information and DNA sequence similarities.

Nodes

The parts of a phylogenetic tree where two lines meet, indicating the timing of speciation and the existence of a common ancestor.

Monophyletic group

A group of organisms sharing a common ancestor, where members within the group are more closely related than those outside.

Convergent evolution

The process by which similar functions or forms evolve independently from completely different ancestors.

Analogous structures

Similar structures with similar functions that evolved from different ancestral structures through convergent evolution, such as bird wings versus butterfly wings.

Homologous structures

Different structures that developed from the same ancestral structure, such as human arms and bird wings.

Taxonomical ranks

A hierarchy of biological classification consisting of eight ranks: domain, kingdom, phylum, class, order, family, genus, and species.

Scientific name

A two-part name for a species consisting of the genus name and the species name, such as Homo sapiens.

Cyanobacteria

Also known as blue-green algae, these photosynthetic bacteria produced oxygen as a byproduct, leading to the Great Oxygenation Event.

Endosymbiosis

The process by which first eukaryotic cells were created when an archaean-like organism engulfed mitochondrion-like bacteria but kept them for energy generation.

Protists

The first eukaryotic organisms on Earth, which were unicellular, microscopic, and similar to modern-day protist-like ancestors.

Big Bang

A massive expansion of condensed matter approximately 15 billion years ago that marked the origin of the universe.

Urey-Miller experiment

A 1952 experiment that simulated early Earth's environment to demonstrate that complex organic molecules, like amino acids, can be formed without living organisms.

RNA world hypothesis

The theory that RNA was used to code for genetic information before DNA because it can self-replicate and possess enzymatic activity.

Domain Bacteria

A domain of tiny, prokaryotic organisms that proliferate via asexual reproduction and are found nearly everywhere.

Domain Archaea

A domain of prokaryotes that are more closely related to eukaryotes than bacteria and are often found in extreme environments like thermal vents.

Kingdom Protista

A collective name for eukaryotes that are neither plant, animal, nor fungi, and are mostly unicellular and microscopic.

Algae

A collective name for any photosynthetic protist, which can be unicellular (like Chlamydomonas) or multicellular (like seaweeds).

Kingdom Plantae

A kingdom of photosynthetic multicellular eukaryotic organisms with cell walls made of cellulose that mostly live on land.

Kingdom Fungi

A kingdom of eukaryotic, immobile organisms with cell walls based on chitin that decompose other organisms and lack photosynthetic ability.

Kingdom Animalia

A kingdom of multicellular eukaryotic organisms that lack cell walls, are mobile, and obtain food by eating other organisms.

Vaccination

A method of providing immunity by giving a signature molecule of a pathogen to the immune system without causing illness.

Phylum Chordata

A phylum within the animal kingdom whose embryos share four features: a notochord, a nerve cord, pharyngeal slits, and a post-anal tail.

Notochord

A flexible rod that runs along the body of all chordate embryos.

Vertebrates

A sub-phylum of chordates characterized by having a vertebral column, or backbone, and a brain developed from nerve cords.

Amniotes

The group of vertebrates, including reptiles, birds, and mammals, fully adapted to dry land through eggs or embryos that are protected from desiccation.

Ectothermic

Animals whose body temperature matches their surrounding environment, such as fish, amphibians, and most reptiles.

Endothermic

Animals, like birds and mammals, that can regulate a constant body temperature regardless of their surroundings.

Mammary glands

Specialized glands in mammals that produce nutrient-rich milk to feed their young.

Monotremes

A unique group of mammals that lay eggs with a shell, such as the platypus and echidna.

Marsupials

Mammals that give birth to tiny, underdeveloped young that then crawl into the mother's pouch to finish developing.

Placental mammals

Mammals that keep their young in the womb for a long gestation period, providing nutrients directly to the embryo via the placenta.

Hominin

A term used to describe humans and all human-like apes.

Bipedal locomotion

The adaptation of standing up and using only two legs for movement, which liberated the arms for other tasks like using tools.

Lampreys

A class of parasitic vertebrates that lack a jaw and fins, using a suction-cup mouth to attach to other fish.

Cartilaginous fishes

Fish with flexible cartilaginous skeletons, jaws, and fins, such as sharks and rays.

Lobe-finned fishes

A class of fish with fins supported by a strong bony skeleton, considered the closest relatives to land-dwelling tetrapods.

Preadaptation

An evolutionary concept where existing structures are repurposed for new functions, like fish fins becoming land animal legs.

Amphibians

The first vertebrates to move to land, characterized by having an 'intermediate' adaptation level and needing water for their non-amniotic eggs.

Metamorphosis

A dramatic body shape change during development, such as when aquatic tadpoles develop legs and lungs to become adult frogs.

Plasmodium

The parasitic protist that causes malaria and is transmitted to humans via mosquito vectors.

Virus

A non-living pathogen composed of genetic material (DNA or RNA) wrapped in a protein coat called a capsid.

Capsid

The protective protein shell that wraps the genetic material of a virus.

Microbiome

A collection of microbes, also called microbiota, that live inside or on the surface of an organism and contribute to health and metabolism.

Pathogens

Disease-causing microbes, which include bacteria, yeast, and viruses.

Antibiotics

Chemicals produced by microbes, like penicillin, that kill a wide range of bacteria.

Superbugs

Bacterial strains that have become resistant to multiple antibiotics through natural selection.