Related Experiment Video
Updated: Jun 5, 2026
08:03
Heuristic Mining of Hierarchical Genotypes and Accessory Genome Loci in Bacterial Populations
Published on: December 7, 2021
Hierarchical selection in modular organisms
1Dept of Ecology, Theoretical Ecology, University of Lund, Ecology Building, S-223 62 Lund, Sweden.
Trends in Ecology & Evolution
|January 14, 2011
Summary
Modular organisms, like plants and corals, grow from repeating subunits called modules. These modules can reproduce independently, forming hierarchical systems that influence survival and reproduction.
Area of Science:
- Developmental Biology
- Evolutionary Biology
- Ecology
Background:
- Modular organisms develop through the repetition of physically interrelated subunits, termed modules.
- These modules can possess features of entire organisms and lack a distinct germ line.
- Somatic embryogenesis allows multiple cell lineages to remain totipotent throughout an organism's or clone's lifespan.
Purpose of the Study:
- To explore the concept of modularity in biological development and reproduction.
- To analyze the hierarchical causal systems formed by modular organisms.
- To understand the implications of modularity for units of selection.
Main Methods:
- Conceptual analysis of modular organism development.
- Examination of reproductive strategies in modular systems.
- Hierarchical analysis of interaction and reproduction levels.
Main Results:
- Modular organisms, including colonial invertebrates and seed plants, exhibit development via repeating modules.
- Reproductive units are module-level due to somatic embryogenesis and totipotent cell lineages.
- Modular repetition creates integrated organisms, colonies, and clones functioning as interactive units.
Conclusions:
- Modular development results in hierarchical causal systems influencing survival and reproduction at the module level.
- The concept of a single functional unit of selection may be an oversimplification for modular organisms.
- Understanding modularity is crucial for comprehending biological complexity and evolution.
More Related Videos
Related Concept Videos
01:46Types of Selection
Natural selection influences the frequencies of particular alleles and phenotypes within populations in several different ways. Primarily, natural selection can be directional, stabilizing, or disruptive. Directional selection favors one extreme trait and shifts the population towards that phenotype while selecting against individuals displaying alternate traits. Stabilizing selection favors an intermediate trait with a narrow range of variation. Deviation from the optimal phenotype towards an...
01:21Frequency-dependent Selection
When the fitness of a trait is influenced by how common it is (i.e., its frequency) relative to different traits within a population, this is referred to as frequency-dependent selection. Frequency-dependent selection may occur between species or within a single species. This type of selection can either be positive—with more common phenotypes having higher fitness—or negative, with rarer phenotypes conferring increased fitness.Positive Frequency-Dependent SelectionIn positive...
02:40The Tree of Life - Bacteria, Archaea, Eukaryotes
The “tree of life” describes the evolution of life and the evolutionary relationships between organisms. The root of the tree is the common ancestor to all life on Earth. All other species radiate from this point, much like the branches of a tree. The numerous tips of these branches on the tree of life represent every living, or extant, species. Extinct species, which are species that no longer exist, can be found towards the center of the tree. Currently, these organisms, both extant and...
02:54Evolutionary Relationships through Genome Comparisons
Genome comparison is one of the excellent ways to interpret the evolutionary relationships between organisms. The basic principle of genome comparison is that if two species share a common feature, it is likely encoded by the DNA sequence conserved between both species. The advent of genome sequencing technologies in the late 20th century enabled scientists to understand the concept of conservation of domains between species and helped them to deduce evolutionary relationships across diverse...
01:09Levels of Organization
Biological organization is the classification of biological structures, ranging from atoms at the bottom of the hierarchy to the Earth's biosphere. Each level of the hierarchy represents an increase in complexity that builds upon the previous level.Molecules Are Composed of Atoms, and Biomolecules Are Assembled from Molecules:The most basic levels include atoms, molecules, and biomolecules. Atoms, the smallest unit of ordinary matter, are composed of a nucleus and electrons. Molecules comprise...
00:57Inclusive Fitness
Most altruistic behavior—in which one animal helps another at a cost to themselves—occurs between relatives. Scientists think these altruistic behaviors evolved because they increase the inclusive fitness of the animal providing help.