Growth Rate Aids Fire Resistance

Biological Strategy

Monkey bread

AskNature Team

Image: Carlos A. Zamora / Flickr / CC BY - Creative Commons Attribution alone

Regulate Reproduction or Growth

Reproduction and growth are two physiological processes that occur in all living systems. There are situations when conditions are right for both, and other situations when continuing either harms the living system because both have a very high energy cost. Reproduction and growth are unique in that both can stop until conditions improve, although stopping either for an extended time can cause problems. An example of regulating reproduction is a process called delayed implantation or embryonic diapause found in some mammals, such as otters. An otter’s embryos sometimes temporarily cease developing and won’t develop further until the female senses that conditions are suitable.

Search this Function

Protect From Fire

Depending on location, fire can be either predictable or unpredictable. In some areas, fires occur in cycles ranging from annual to hundreds of years. Where fire is cyclic, living systems must be able to not only survive fire, but to quickly recover following it. For example, pine trees that live in areas with periodic fires have thick bark that provides insulation, thereby protecting the tree’s living tissue.

Search this Function

Flowering Plants

Clade Angiosperms (“receptacle seed”): Dandelions, oaks, grasses, cacti, apples

With 416 families containing some 300,000 known species, angiosperms are the most diverse group of plants, and they can be found around the globe in a wide variety of habitats. They are characterized by seeds that grow enclosed in ovaries, which are enclosed in flowers. The floral organs then develop into fruits of myriad kinds and dimensions, from simple seed casings on maples to elaborate fleshy growths like papayas. The oldest flower known from fossils, Montsechia vidalii, appeared during the Jurassic Period 130 million years ago. They are the primary food source for herbivorous animals, which in turn makes them the indirect food source for carnivores as well.

Search this Living System

The camel's foot tree, found in the African savanna, resists fire due to its ability to quickly resprout from underground storage structures.

“Bark properties (mainly thickness) are usually presented as the main explanation for tree survival in intense fires. Savanna fires are mild, frequent, and supposed to affect tree recruitment rather than adult survival: trunk profile and growth rate of young trees between two successive fires can also affect survival. These factors and fire severity were measured on a sample of 20 trees near the recruitment stage of two savanna species chosen for their contrasted fire resistance strategies (Crossopteryx febrifuga and Piliostigma thonningii [Synonym: Bauhinia thonningii]). Crossopteryx has a higher intrinsic resistance to fire (bark properties) than Piliostigma: a 20-mm-diameter stem of Crossopteryx survives exposure to 650°C, while Piliostigma needs a diameter of at least 40 mm to survive. Crossopteryx has a thicker trunk than Piliostigma: for two trees of the same height, the basal diameter of Crossopteryx will be 1.6 times greater. Piliostigma grows 2.26 times faster than Crossopteryx between two successive fires. The two species have different fire resistance strategies: one relies on resistance of aboveground structures to fire [Crossopteryx], while the other [Piliostigma] relies on its ability to quickly re-build aboveground structures.” (Gignoux et al. 1997:576)

Last Updated August 18, 2016

References

Journal article

Alternative fire resistance strategies in savanna trees

Gignoux, J.; Clobert, J.; Menaut, J. C.

embedly preview

Reference

Other Biological Strategies

A cicada sits on a blade of grass with a parasitic fungus visible where its abdomen should be.

Biological Strategy

Fungus Turns Cicadas Into “Salt Shakers of Death”

Cicada

Parasitic fungus secretes behavior-modifying chemicals into cicadas that dramatically changes their sex drive.

brown white and black fowl bird stands on top of pike of sticks against a natural forest background

Biological Strategy

Birds Incubate Eggs With Heat From Compost

Mallee fowl

The nests of mallee fowl provide warmth for eggs by use of rotting vegetation and an insulating layer of soil.

a brown moth with large antennae sits on a grass stem against a grassy background and blue sky

Biological Strategy

Moths Make Sense of Barely-There Scents

Moths

Moth antennae sense specific airborne molecules in minute concentrations.

Octopuses congregating at hydrothermal vents

Biological Strategy

Octopuses Use Hydrothermal Vents as Nurseries

Muusoctopus robustus

Thousands of octopuses nurture their eggs in hydrothermal vent communities by utilizing warmth for energy-efficient development.

Naked mole rat babies being tended to by Queen and guards to keep warm

Biological Strategy

Extra Egg Cells Maintain Fertility

Naked mole rat

Naked mole rat queens stay reproductive through long lives by maintaining the health of a large number of egg cells.

Biological Strategy

Stress Response Suppressed to Prioritize Reproduction

Birds

In the face of environmental stress, birds with fewer chances to breed suppress their stress response, keeping their focus on reproduction instead of survival.