Carnivorous Plants: Science Fiction or Science??

What in the world is a carnivorous plant?

Must be able to attract, capture and kill animals (mostly insects)

Also must digest the animal

Can survive without eating meat, though.

Most are small (<1 m tall) but one vine species can grow to be 10 m long

Where in the world can I find these plants?

Everywhere except Antarctica!! More abundant in Australia, southeast Asia

and North America Even Alachua county has them!! 600 species and sub-species, but not all

related to each other

Let’s Review. . . 1) What are the 4 traits of a carnivorous plant? They attract, capture, kill and digest animals2) Do non-carnivorous plants share any of these traits? Non-carnivorous plants can attract insects 3) Do they need to eat meat to survive? No-they have been grown in labs without meat4) Where in the world can you find these plants? Everywhere except Antarctica5) How many species are there? Are they all related? 600 species and sub-species; they are not all related (convergent evolution)

What habitat do they live in? The genus Utricularia is

aquatic (freshwater) Mainly found in nutrient

poor wetlands (ex. Bogs) Decaying plants release

acidic compounds Microorganisms cannot

function Difficult for plants to get

nutrients from acidic soil

Why aren’t all plants meat-eaters?

Carnivorous plants have an advantage over non-carnivorous plants in nutrient poor habitats

In habitats with more nutrients, non-carnivorous plants do better because they do not have to put energy into special structures.

Let’s Review. . . 1. What is the most common habitat of carnivorous plants?

Nutrient poor wetlands.2. What feature of their habitat allowed them to evolve

carnivory? The lack of nutrients available in the soil.3. Why does the habitat have this feature?

pH of water is low, so bacteria cannot help decompose plants and plants cannot take up nutrients as easily.

4. Why do non-carnivorous plants do better in habitats with more nutrients? Because they do not have to put energy into special structures to capture prey like carnivorous plants do.

What animals do they eat? Mostly Insects and spiders

(gnats, flies, moths, wasps, spiders, butterflies, beetles and ants)

Freshwater species eat small water animals and fish and mosquito larvae

Some capture small amphibians (frogs) and small birds and rodents have been found in some tropical species!!

Some species even eat insect and bird excrement!!

How do these plants capture prey? Can be sweet-smelling or

brightly colored to attract prey to their trap

There are 2 types of traps Active: Use rapid

movement (ex. Venus fly-trap, Utricularia)

Passive: sticky hairs or a long tube with hairs that trap prey

Active or Passive?

Let’s Review . . . 1. What do carnivorous plants commonly eat? Insects, spiders and aquatic plants eat small animals, fish

and mosquito larvae. 2. Name 3 less common things they have been found to eat. Amphibians, birds and rodents 3. What are the two types of traps they use to catch their

prey?Active and passive

4. Name a variation of each type of trap. Active: bladderwort (Utricularia), venus fly trap

(Dionaea). Passive: pitcher plant has a pitfall trap; most carnivorous plants have sticky hairs.

How do they digest their prey? Most produce

digestive enzymes Some rely on bacteria Some use both

bacteria and digestive enzymes

How do we affect carnivorous plants?

Only 3-5% of carnivorous plant habitat left!

Draining wetlands For roads, homes, stores and water

Suppressing fire Many ecosystems need fire to stay

healthy Pollution from homes and

agriculture Gets into water and destroys plants

Poaching the plants: Many are endangered.

Final Review and Wrap-Up1) What are the 4 traits of a carnivorous plant? Do non-carnivorous

plants have any of these traits? Attract, capture, kill and digest animals. Yes, many plants attract

insects for pollination. 2) How many species are there of carnivorous plants? Are they all

related? 600 species and sub-species that are not all related (convergent

evolution) 3) In what habitats and parts of the world are they found? Found mostly in nutrient poor wetlands everywhere except

Antarctica. 4) What feature of their habitat allowed them to evolve carnivory? Lack of nutrients

Final Review and Wrap-Up cont…1) What are some of their common prey species? Some less common

ones? Insects and spiders. Less common are amphibians, birds and rodents.2) What are the two ways they capture their prey? Active and passive traps. 3) How do they digest their prey (hint: what do some use to help them

digest?)? Some secrete digestive enzymes, some use enzymes and bacteria to

help them digest (symbiosis). 4) How have humans affected carnivorous plant populations and their

habitat? Humans have drained wetlands, suppressed fire, polluted water, used

too much water and poached plants.

All pictures used in this powerpoint presentation were from www.sarracenia.com