Carnivorous Plants Quiz

Carnivorous plants have adapted to grow in nutrient-poor environments and derive nutrients from trapping and consuming animals or protozoans. They can be found on all continents except Antarctica and are represented by more than a dozen genera and at least 583 species. Carnivorous plants have evolved independently at least 12 times in five different orders of flowering plants. True carnivorous plants are considered carnivorous if they have five traits, including attracting and retaining prey. There are five basic trapping mechanisms found in carnivorous plants, including pitfall traps, flypaper traps, snap traps, bladder traps, and lobster-pot traps. The Venus flytrap, pitcher plant, and bladderwort are examples of carnivorous plants with the key traits of trap leaf development, prey digestion, and nutrient absorption. Over 300 protocarnivorous plant species show some but not all of these characteristics, and roughly one quarter of carnivorous plant species are threatened with extinction due to human actions. Charles Darwin was the first person to recognize the significance of carnivory in plants.Evolution and Adaptation of Carnivorous Plants

• Carnivorous plants have specialized adaptations to attract, capture, and digest prey, which provides them with nutrients to survive in habitats with low soil nitrogen and phosphorus.

• Different types of traps, such as pitfall, flypaper, snap, and suction traps, have evolved independently in multiple lineages of carnivorous plants.

• Some plants, such as Roridula, produce sticky leaves that trap insects, but do not directly benefit from them, as they form mutualistic symbiosis with species of assassin bugs that eat the trapped insects.

• The digestive fluid of carnivorous plants, produced by specialized multicellular secretion glands, contains hydrolytic enzymes that decompose the body of the prey, releasing nutrients that the plant can absorb through its leaves.

• The evolution of carnivorous plants is obscured by the paucity of their fossil record, but genetic evidence suggests that carnivory developed by co-opting and repurposing existing genes which had established functions in flowering plants.

• The evolution of carnivorous plants is believed to have started with a sticky, hairy leaf that could catch and retain drops of rainwater, leading to the development of pitfall and flypaper traps.

• The cost-benefit model for botanical carnivory suggests that the trait could only evolve if the increase in nutrients from capturing prey exceeded the cost of investment in carnivorous adaptations.

• Rapid plant movements can result from actual growth or from rapid changes in cell turgor, which allow cells to expand or contract by quickly altering their water content, and are used in active glue traps, such as those of the Venus flytrap.

• Recent taxonomic analysis of the relationships within the Caryophyllales indicate that the Droseraceae, Triphyophyllum, Nepenthaceae, and Drosophyllum are closely related, but embedded within a larger clade that includes non-carnivorous groups.

• Botanical carnivory has evolved in several independent families of angiosperms, showing that carnivorous traits underwent convergent evolution multiple times to create similar morphologies across disparate families.

• Genetic testing published in 2017 found an example of carnivory in the roots of Philcoxia, a plant in the family Plantaginaceae, which has subterranean stems and leaves that capture nematodes.

• The adaptation of carnivorous plants to extreme habitats, such as high-light environments and waterlogged soils, allowed for the trade-off between photosynthetic leaves and photosynthetically-inefficient, prey-capturing traps, and favored the evolution of plant adaptations that allowed for more effective, efficient carnivory.Ecology and Modeling of Carnivory in Plants

• Carnivorous plants are rare and are usually found in habitats with extremely limited soil nutrients but abundant sunlight and water.

• Carnivorous plants use animals as a source of nitrogen, phosphorus, and potassium to grow and reproduce.

• The leaf of a carnivorous plant is used as both a trap and for photosynthesis, but changing the leaf shape to make it a better trap decreases its efficiency at photosynthesis.

• The potential for plant growth is net photosynthesis, which is the total gross gain of biomass by photosynthesis minus the biomass lost by respiration.

• A carnivorous plant will have both decreased photosynthesis and increased respiration, making the potential for growth small and the cost of carnivory high.

• The more carnivorous a plant is, the less conventional its habitat is likely to be.

• Carnivory only pays off when the nutrient stress is high and where light is abundant.

• Many carnivorous plants shut down in some seasons, and some plants give up carnivory temporarily when there is too little light or an easier source of nutrients.

• Carnivorous plants are poor competitors because they invest too heavily in structures that have no selective advantage in nutrient-rich habitats.

• Many organisms interact with various carnivorous plants in sundry relationships of kleptoparasitism, commensalism, and mutualism.

• Approximately half of the plant species assessed by the IUCN are considered threatened due to habitat loss, collection of wild plants, pollution, invasive species, residential and commercial development.

• Conservation efforts are necessary to protect threatened carnivorous plant species.Threats to Carnivorous Plants and their Conservation: A Summary

• Carnivorous plants are under threat from a variety of human activities including habitat loss, energy production, mining, transportation services, geologic events, climate change, and severe weather.

• The same genus of carnivorous plants face similar threats.

• Threats to carnivorous plants vary greatly by continent, with North America having the most threats (19 species), followed by Asia (15 species), Europe (7 species), South America (6 species), Africa (2 species), and Australia (1 species).

• Sarracenia is an indicator species that positively associates with threats to carnivorous plants.

• Certain threats are positively correlated with each other, such as residential and commercial development, natural systems modifications, invasive species, and pollution.

• Conservation research is working to quantify the effects of pollution and other threats on carnivorous plants and to quantify extinction risks.

• Only 17% of carnivorous plant species have been assessed by the IUCN as of 2011.

• Conservation of carnivorous plants is important for maintaining important ecosystems and preventing secondary extinctions of specialist species that rely on them.

• A holistic approach, targeted at the habitat-level of carnivorous plants, may be necessary for successful conservation.

• Carnivorous plants are considered a curiosity or rarity in horticulture, but are becoming more common with mass-production tissue-culture propagation techniques.

• Most carnivorous plants require rainwater or distilled/deionized water as they are intolerant of soil-borne nutrients.

• Insects may be fed to carnivorous plants by hand to supplement their diet, but they cannot digest large non-insect food items.