Biology Now, 2e

The Dirt on Black-Market Plants ■ 289

egg and sperm produces a single cell, called a

zygote, which then divides to produce a multicel-

lular structure called an embryo. Sexual reproduc-

tion is one means by which natural populations

become genetically diverse; it is why there are an

estimated 400,000 species of plants on Earth.

Through these unique traits—a true nucleus,

cellular compartmentalization, multicellularity,

and sexual reproduction—eukaryotes have

evolved into amazingly diverse and dynamic

species. Of these species, Phelps was particularly

concerned about orchids. In addition to spend-

ing time in Bangkok, the budding ecologist

devoted months traveling along Thailand’s

borders with Laos and Myanmar, wandering

hours upon hours through wildlife markets.

Over time, he built local networks that allowed

him to interview more than 150 plant harvesters

and intermediaries, including market traders,

online traders, nursery owners, and more.

Orchids are, on paper, one of the most

heavily protected families, representing almost

75 percent of all species, plant or animal, for

which international trade is regulated. Artifi-

cially propagated orchids can be traded legally,

but wild orchid species in Southeast Asia are

protected, says Phelps: “None should be collected

from the wild, unless you have specialized

permissions.” Yet, as he came to discover, there is

no enforcement of those protections in Thailand

or across the region. Orchids and other orna-

mental and medicinal plants were not only being

traded, but also poached from nearby countries,

threatening the very existence of certain species

and the overall biodiversity of the region.

Green-Fingered Thieves

Under the dark of night, the thieves worked

swiftly. Armed with shovels, they snuck past

the closed gift shop and made a beeline for their

quarry. They knew exactly what to take.

The next morning, the staff at the Quail

Botanical Gardens in Encinitas, California,

discovered the theft. In a frantic effort, they

spread details of the heist to local newspapers,

television, and online community message

boards. Their quick action paid off; the loot

became too hot. Within days, an anonymous tip

led authorities to a rural road where the thieves

opportunists, or mixotrophs, organisms that use

energy and carbon from a variety of sources to

fuel their growth and reproduction.

Although most protists are harmless, many of

the best-known protists are pathogens (disease-

causing agents), such as Plasmodium, which is

transmitted by mosquitoes and causes malaria,

and To x o p l a s m a g o n d i i, passed to humans

through poorly cooked food or cat feces. Toxo-

plasmosis typically causes mild flu-like symp-

toms, but can be passed from mother to child in

utero and cause more severe symptoms.

Two Cells Are Better Than One

Multicellular forms evolved several times among

different lineages of the eukaryotes. A multicel-

lular organism is a well-integrated assemblage

of genetically identical cells, in which different

groups of cells perform distinctly specialized

functions. This functional compartmentaliza-

tion makes it easier for multicellular eukaryotes

to sense and respond to the external environ-

ment, through the use of complex structures

such as leaves, fruit, eyes and wings.

Multicellularity also enables an individual

organism to grow large, which can be advantageous

for evading potential predators. A bigger individ-

ual can also gather resources from its environment

more effectively than can a smaller individual.

Having more resources, such as light or food, may

translate into producing more surviving offspring,

the ultimate measure of biological success.

To make those offspring, eukaryotes repro-

duce via either asexual or sexual reproduction.

Asexual reproduction is common among species

in this domain and generates genetically iden-

tical offspring. Protists, for example, can split

into two in a process similar to binary fission in

prokaryotes. Many plants reproduce asexually

by fragmenting into pieces, each piece develop-

ing into a new individual.

But it is through the second type of reproduc-

tion that eukaryotes have made an indelible mark

on our planet. By combining genetic information

from two parents, sexual reproduction produces

offspring that are genetically different from each

other and from both parents. Although their life

cycle is distinctly different from that of animals,

plants similarly produce embryos: the fusion of