The Web of Life (chapter) Synopsis
“All species are connected in the web of life.” ~ Italian ecologist Giovanni Strona
Defining Life
▫ 2 facets characterize life: form and function; but biomechanics do not sufficiently characterize life. Life is about information and its energetic application. As a working definition, life is ecologically applied intelligence and intelligence is ecologically appropriate behavior.
Communication
Communication is transmission of information. Some is intentional (signals); much is not. Reception is neither incidental to communication nor is it requisite to the definition of communication.
▫ The tenor of communication varies depending on the relation between sender and receiver. Subtlety is used for intimacy, clamor for aggression.
▫ Metacommunication is a communication qualifier: a way of contextually qualifying behaviors that follow. An example of metacommunication is a preface to play: indicating that what could otherwise be interpreted as aggression is intended in the spirit of fun.
Some animals get attention by communication substitution: signaling in a way that relies upon a strong pre-existing reception, then adjusting the receiver’s response to suit the sender.
▫ Honesty and deception are evolved communication forms. Nature adaptively insists upon honesty under certain circumstances, such as when deception may be unnecessarily harmful to the sender. Conversely, deception finds favor when a sender considers it potentially helpful. Fear typically drives deception.
Communications Media
▫ The physical media for communication are chemistry (molecules), used by all life; electromagnetism (light, heat, electricity); and mechanical vibrations (sound).
▫ Communication modalities evolved in the context of habitat. 3 facets pertain: 1) what travels best between sender and receiver; 2) what delivers a relatively robust signal; and 3) the extent to which the interests of the sender and receiver coincide.
Cellular Communication
▫ Within and among cells, communication is essential and constant. The term cell signaling signifies the communication protocols employed.
▫ Cells rely upon intelligence received by communication to plan, schedule, and determine activities and their vigor.
Biosphere
▫ The biosphere comprises the sum of the Earth’s ecosystems. Geographically, the biosphere is the zone of life on Earth, bounded between outer space and within the lithosphere.
▫ The 4 elements (bioelements) of a biosphere are: the atmosphere (air), hydrosphere (water), lithosphere (land), and biota (life). Life has long played an active role in influencing abiotic bioelements in the biosphere.
▫ The biosphere is a gyre with self-organized criticality for biota.
▫ Ecology refers to relations among bioelements.
▫ A biome is a region where organisms live in similar conditions, both geographically and climatically.
▫ An ecosystem comprises the community of organisms – biota – in a biome, along with the abiotic (non-living) bioelements within.
▫ A habitat is the environment in which a species’ population lives. There are as many habitats within an ecosystem as there are species.
▫ The biota in a biome invariably form an entangled community of energy producers and consumers. The health of a biome depends upon interactive biotic balance.
▫ A food web comprises the food interrelations between biota. A food chain, or trophic pyramid, is a hierarchical perspective of the food web: from producers (plants and other organisms which take their energy from inorganic sources) to consumers: herbivores (plant consumers) and predators (animal consumers). Saprovores clean up the leftovers: decaying organic matter. Potent pilferers – parasites and pathogens – also play a significant role in the food web.
▫ Trophic cascade encapsulates the dynamic of predators preventing overgrazing by chewing away at the herbivore population, thusly increasing plant growth.
▫ A keystone species directly or indirectly engenders other life in an ecosystem. The roles of many integral to an ecosystem’s biota, particularly the microbial, are not readily apparent.
Many biomes have migrants upon which local populations partly rely. Salmon, and even dust, are exemplary. Migration interconnects life between biomes.
▫ Parasites are pervasive shapers of fortune for other life. Their variety equals that of nonparasitic beings. As epiparasites evidence, even parasites are not immune from parasitism.
▫ Species richness signifies a rough tally of the species in an ecosystem; it and the topology of predator-prey linkages are intertwined as an evolutionary balancing act.
▫ Biodiversity encompasses the diversity of life. Biodiversity typically multiplies the ongoing possibilities for life. Biodiversity indicates the health of life within a biome.
▫ Carrying capacity is the hypothetical maximum population size of a species given the constraints imposed by the environment.
▫ The lithosphere concertedly moves in supercontinent cycles. Corresponding to these lithospheric cycles are climate cycles between the extremes of icehouse and hothouse. Owing to human pollution, Earth is now heading toward hothouse.
