[ 237 ] Life Science GED ® TEST SCIENCE FLASH REVIEW • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • The monarch butterfly at the larval stage eats milkweed that is full of a poisonous chemical known as cardiac glycoside that is harmful to most vertebrates. Once the butterfly has reached its mature butterfly form, if a bird or other vertebrate eats the butterfly, it finds the butterfly distasteful and will become sick. Because of this, birds and other predators avoid eating monarch butterflies. The relationship between the monarch butterfly and milkweed is an example of _______. • parasitism • commensalism • mutualism Burdocks are weeds that have seeds with long, curved spines attached to them. They are most often found along roadsides, on barren land, and in fields. The spines of the seeds easily catch onto fur and clothing of passing animals and humans, which then carry them and drop them off in other areas. This allows the seeds to disperse while the carriers remain unharmed. This is an example of _________. • parasitism • commensalism • mutualism A certain kind of bacteria lives within the intestine of humans and other animals. Humans cannot always digest all the foods that they eat. The bacteria eat that food and partially digest it, allowing the human to finish the job. The bacteria get food and the humans benefit by being able to digest the food as well. This an example of ________. • parasitism • commensalism • mutualism