Chapter 13 - The sex life of plants

Darwin's Studies on Plant Movements and Cross-Fertilization

• Darwin conducted experiments to determine if plants have an equivalent to nerves and muscles, attempting to gas and drug them, but the drugs did not work.
• He studied Utricularia, or bladderworts, which are aquatic plants that trap prey, such as mosquito larvae, in little bubbles filled with water.
• Darwin's 1865 article "Movements and habits of plants (Climbing Plants)" was later expanded into a book, in which he classified climbing plants based on their methods of ascent.
• He discovered that climbing plants, lacking muscles and nerves, move through spiral growth, and found that they climb to obtain more light and reduce competition for sunlight.
• Darwin used time-lapse photography to study plant movements, marking each dot with a timestamp to track the growth patterns of climbing plants.
• In his book "Cross and self-fertilisation," Darwin argued for the benefits of cross-fertilization, showing that self-fertilized seedlings are weaker and less numerous.
• In his second book, "The different forms of flowers," Darwin explored the structures that promote cross-pollination, such as heterostyly, where flowers have different lengths of styles and stamens to prevent self-pollination.
• He used diagrams to illustrate how heterostyled flowers increase the chances for cross-pollination, ensuring that pollen from one flower type does not fertilize the same plant.
• Darwin studied Lythrum salicaria (purple loosestrife), a plant with three different flower types to ensure cross-pollination, resulting in six combinations of pollination processes.
• In his third book, "The power of movements of plants," written with his son, Francis Darwin, he explored plant movements in response to light and gravity, including how plants lean towards light and "sleep" at night to protect themselves.
• He applied his theories to all parts of nature, finding that similar rules applied to new cases and that old structures had evolved to perform new functions.
• Despite his scientific contributions, Darwin faced criticism and ridicule, as seen in a cartoon portraying him as an ape in a tree, reflecting the tendency to mock him.

Darwin's Contributions to Botany

• In his book on orchids, Darwin demonstrated that plants have intricate adaptations, similar to animals, and that natural selection is the scientific explanation for these adaptations.
• The emergence of flowering plants and grass after the extinction of dinosaurs was a significant point in Darwin's book.
• Duke of Argyll criticized Darwin's god-less version of evolution, while others like Asa Gray praised Darwin for his work on orchids.
• Darwin's hobby in botany turned into a successful endeavor, demonstrating that his theory could explain intricate details in nature.
• Darwin's later works focused on botany, particularly his study on insectivorous plants, such as the Common Sundew.
• In his book "Insectivorous Plants," Darwin detailed the structure of the Sundew and its behavior, showing how they react to animal substances containing nitrogen.
• Darwin's experiments with Sundew led him to conclude that the plant acquires nitrogen through the digestion and absorption of insects, a behavior that evolved in response to poor soil conditions.
• Darwin's research on Sundew led him to speculate that other plants with similar behaviors may have evolved from hairs that trapped raindrops, leading to the trapping of insects.
• Darwin also studied the Venus flytrap, another plant with modified leaves to catch insects, and pondered on the evolutionary origins of such behaviors.
• Darwin's exploration of botany and his discoveries about plant behaviors, such as the Sundew's nitrogen acquisition, contributed significantly to the understanding of plant evolution.
• Through his studies on various plants, Darwin demonstrated the role of natural selection in shaping the behaviors and adaptations of plants in response to their environment.
• Darwin's contributions to botany, particularly his studies on insectivorous plants, shed light on the intricate adaptations and behaviors of plants, further enriching our understanding of evolutionary processes in the plant kingdom.

"Darwin's Studies on Plant Movements and Cross-Fertilization" Quiz Test your knowledge on Charles Darwin's groundbreaking studies on plant movements and cross-fertilization. Explore his experiments with climbing plants, time-lapse photography, and the benefits of cross-fertilization. Learn about his research on Utricularia, heterostyly, and the power of plant movements in response to light and gravity.