Lecture Notes on Multicellularity

Flashcards on Multicellularity

Multicellularity

The generation of organisms containing more than one cell, contrasting with unicellular organisms.

Unicellular Organisms

Organisms composed of a single cell responsible for all life processes such as motility, prey capture, and gas exchange.

Multicellular Organisms

Organisms with specialized cell types for different functions (e.g., epithelial cells, blood cells, nerve cells) that must act together.

Prokaryotes

Cells without a proper nucleus or membrane-bound cytoplasmic organelles, enclosed by a single outer membrane; includes bacteria and archaea.

Archaea

Microorganisms similar to bacteria but with unique properties; some are extremophiles that can survive in extreme conditions.

Eukaryotic Cell

Cells with a proper nucleus and membrane-bound organelles, formed from components of both bacteria and archaea.

Phylogenetic Tree

A diagram showing the evolutionary relationships between different organisms, illustrating the origin and diversification of life forms.

Choanoflagellates

Single-celled organisms closely related to animals, used to study the transition from unicellularity to multicellularity.

Division of Labor

Specialization of cells for particular functions within a multicellular organism, allowing for more complex morphologies and behaviors.

Simple Multicellularity

Organisms consisting of multiple cells that have come together to form a colony, with limited coordination and differentiation between cells.

Complex/Obligate Multicellularity

Organisms with distinct and differentiated cell types that undergo a regulated developmental process and require multicellularity for survival.

S. Rosetta

A type of choanoflagellate that can exist as single cells or form colonies, enhancing their ability to capture prey or protect from predation.

Cheater Cells

Selfish cells in simple multicellular organisms that take advantage of the altruism of others, limiting the benefits of cooperation.

Aggregate Multicellularity

A process where separate cells come together and merge to form a cluster, often in response to adverse conditions, and is reversible.

Clonal Multicellularity

A process where serial cell division occurs without dispersion of sister cells, typically starting from a single cell (zygote) and leading to a fully formed organism.

Blastocyst

An early stage of embryonic development in animals, formed from the division of a zygote into clones of cells.

Sponges

A type of animal composed of two main cell types: spicules for structural support and choanocytes for movement and prey capture.

Volvocine

A line of aquatic green algae used as a model system to study the evolution of multicellularity, with forms ranging from single-celled to complex multicellular.

Cancer

A condition where cells lose cooperation and altruism, acting independently and prioritizing their own needs over the organism's, resembling unicellular organisms.