Some trees stretch human time scales into the realm of centuries. Giant sequoias and coast redwoods grow to extreme sizes because their vascular systems move water efficiently and their thick bark resists fire and insects. Their crowns lift leaves into bright, moist air where photosynthesis runs for many months each year. Old trees anchor entire ecosystems: their trunks house owls and bats, their roots stabilize slopes, and their fallen logs feed fungi that return nutrients to the soil. Protecting these giants means preserving the webs of life that depend on them.
Comprehension Check
Which feature helps giant trees survive fires and pests?
Why do old trees matter to forest ecosystems?
Plants that Hunt
Carnivorous plants evolved traps to capture insects in places where soil is poor in nitrogen. Pitcher plants lure prey with nectar and color; once inside, slick walls and digestive fluids turn the leaf into a pitfall. Venus flytraps snap shut when tiny hairs are touched twice within seconds, a clever way to avoid wasting energy on raindrops. Sundews use sticky droplets that act like glue and then curl their leaves to digest the meal. These species still perform photosynthesis, but their traps provide bonus nutrients that ordinary roots cannot supply in harsh habitats.
Comprehension Check
Why do some plants evolve carnivory?
How does a Venus flytrap avoid closing by accident?
Hidden Messages in the Green World
Plants communicate using chemistry and underground networks. When caterpillars chew a leaf, the plant releases airborne signals that warn nearby plants to boost defenses or that attract wasps which parasitize the pests. Below ground, many roots partner with fungi in mycorrhizal webs that trade nutrients for sugars. Through these connections, plants can share signals and sometimes move small amounts of carbon and nitrogen. This communication is not language, but coordinated biology that helps communities survive droughts, diseases, and hungry herbivores.
Comprehension Check
What is one benefit of the chemicals released by damaged leaves?
What do mycorrhizal networks exchange with plant roots?
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