Sunday, January 28, 2018



Gary Williams

California Academy of Sciences

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Life Forms of the Earth

The diversity of life on our planet is truly astounding, overwhelming, only partially manageable, and will never be completely knowable or understandable. Join me here for varying topics of biodiversity science, as we seek to discover, appreciate, and protect our fellow life forms on the only place in the universe that we know to harbor life. 

Many life forms and species are familiar to us, but most are not. We have a tendency to label the unfamiliar as exotic, odd, strange, or peculiar. The phrase 'Life form anomaly' is defined here as an organism that deviates from out perception of what is normal, standard, or to be expected. See below for a potpourri of lifeforms that fit this category - as well as species not normally seen or encountered and therefore unfamiliar to us.

In fully expanded feeding mode

The gorgonian coral, Astrogorgia sp., with polyps fully extended in a strong bottom current for maximum uptake of microscopic plankton and particulate matter

A foraminiferan (otherwise known as a foram) 

A shelled, single-celled ameboid organism found on the surface of a coral on a Philippine coral reef

A fellow citizen of planet Earth ...

 ... that shares a common ancestor with us (Homo sapiens) --- probably sometime in the early Cambrian Period around 525 million years ago!

A sabellariid polychaete worm in its tube in the sand, Sabang, Mindoro Island, Philippines

What? Corals live in cold, dark, deep Antarctic seas?

Well yes, some actually do. In fact, corals can be found in all of the world's oceans from polar seas to the tropics, and at all depths from sea level to the bottom of the deepest part of the oceans.  There are estimated to be over 5000 species of corals currently living on the planet, a great many of which live at extreme depths in colder regions of our watery planet.

A deep-sea sea pen from Antarctic Seas (Umbellula sp.)
 Illustration by Alyssa Oglesbee, California Academy of Sciences, 2012

Only a portion of the narrow stalk is shown here. Its actual length is about 3.5 meters (over 10 feet). The disk containing the feeding polyps is about the size of a small dinner plate.

What is an endemic species?

An endemic species is one that is restricted to a particular geographic region. For instance, this species of newt is known to occur in only three coastal counties of northern California.

Red-bellied newt (Taricha rivularis), Coast Range Mountains, California 

Urban biodiversity?

Surprising examples of wild species can even be found within city limits where the natural environment has been substantially altered, such as in this dense aggregation of mushrooms.

Mycena mushrooms (Mycena sp.), San Francisco, California

High diversity in a small area

A dense assemblage of many species of hard corals, soft corals, and sea fans on a coral reef at Lubang Island, Philippines Archipelago

High abundance and biomass, but low diversity in a large area

A mono-specific stand of Blue Oaks (Quercus douglasii) on a hilltop in the California Coast Range

Microscopic marine organisms in a plankton soup

Most of what is alive all around us, we can't even see without help. Here is a scanning electron microscope image of a diatom, measuring up to a whopping total diameter of 0.03 mm! 
SEM by Cerise Chen, California Academy of Sciences

Life on Dead Wood

The fungus Daldinia sp. (above). Unlike mushrooms, which produce spores on gills underneath the cap, sac fungi  such as these produce spores through pores on the outer surface of the cap (below). Not only are two fruiting bodies of the fungus seen here on this dead tree branch, but the branch is also inhabited by a diversity of lichen species as well.

Not far away, but seen by few

Black-footed Albatross (Phoebastria nigripes) offshore of the California coast near the Farallon Islands

Crowded living in an underwater jelly ball

A crowded aggregation of immobile single-celled individuals known as cryptomonads; this state may occur regularly in the organism's life cycle in a jellylike matrix known as the palmella stage

Wild species in unexpected places

An extraordinary diversity of lichen species growing on the side of a barn (left) and on an old picket fence (right)

Restricted to a vital, but endangered habitat

A butter-yellow daisy (Blennosperma nanum) found in California wetlands such as vernal pools

Hidden, minuscule, and out of sight 

Two diatom skeletons hidden in a pit of a sand grain, on a South African beach

A species hidden, cryptic, nocturnal, and not often seen

The Sugar Glider (Petaurus breviceps), a small marsupial from Papua New Guinea

Playing tricks with light

Some corals are capable of fluorescence. Fluorescent compounds in their tissues absorb shorter (more energetic) wavelengths of light, then reemit some it at longer (less energetic) wavelengths, the remainder is lost as heat.  This process changes the color, which can often be striking and unexpected. Fluorescence may be important in survival of a species, but the exact role is not clear. One idea is that the compounds may act as a sunscreen, protecting the coral and the symbiotic algae in their tissues from too much harmful ultraviolet radiation.

A reversal: plants that eat animals

The insectivorous Madagascar Pitcher Plant (Nepenthes madagascarensis)

Very small, and living at the bottom of the sea

No, it's not an extra-terrestrial conveyance vehicle. It's a benthic foraminiferan: an amoeboid protozoan with a calcium carbonate shell, less than 1 mm  in length!

No, not related to vegetables!

Actually it’s a predatory undersea animal. Some soft corals (like this species of Umbellulifera from about 60 feet in depth in the northern Philippines), as in some other members of the family Nephtheidae, often resemble edible plants of the cabbage family such as broccoli or cauliflower.

A denizen of the night on tropical islands of the Indo-Pacific

The Coconut Crab (Birgus latro), a terrestrial hermit crab, is also called the palm thief or robber crab

A green realm underfoot

Grape-like clusters of algae (Botrydium sp.) known as a xanthophyte growing on damp bare soil; each of the largest spheres seen here are about 1/2 mm in diameter

Life in an aquatic realm --- a drop of water

A single-celled ciliate, the protozoan known as paramecium (Paramecium sp.); each individual shown here is about 1/10th of a mm in length

Explosive population growth with toxic results

Conspicuous display of  a summer "red tide" off the coast of San Francisco, California 

19th century stylized illustrations of various dinoflagellate species, by Ernst Haeckel

The term Red Tide is actually a misnomer since tides have nothing to do with it. A red tide is a periodic, red-orange, dense concentration or population explosion (also called an algal bloom) of single-celled, microscopic organisms of the ocean plankton known as dinoflagellates, most often seen in the warmer months of late Spring or Summer

Sometimes, red tides can be described as harmful algal blooms, because of the high production of natural toxins. Algal blooms can also lead to the depletion of dissolved oxygen in localized areas, causing the death of other organisms. Paralytic Shellfish Poisoning (PSP) occurs when the neurotoxins produced by phytoplankton such as some dinoflagellates, cyanobacteria, and diatoms, are concentrated in shellfish (like mussels and clams) to highly toxic levels and are consumed by people.

Building with Paper

Paper Wasps (Polistes spp.) collect plant fibers from stems and dead wood and mix them with saliva to build nests of papery material. The genus Polistes contains about 300 species worldwide