B.10C Living Together Does Not Always Work – 04

There are three different species of orcas in the Pacific northwest. The “resident”, “transient” and “offshore” orcas. The “resident” orcas feed only on salmon. They are found in nearby coastal waters. The “transient” orcas feed only on marine mammals. They move north to south along the coast. The “offshore” orcas are found well beyond the coast. Sharks are an important part of their diet. The social structure of each population is different. They also communicate in different ways. They do not interbreed even though they are found in the same areas.

Did you know that there are many species of fireflies? Each of them has their unique flashing lights. Members of the same species find mates using their own unique flashing patterns. This prevents interbreeding between species.

Have you seen a blue footed booby dance? Well, the Blue footed booby shares its habitat with other species in the same genus. But it never mates with the other species. It has a complex courtship ritual. The female Blue footed booby selects a mate after watching the entire ritual dance. This is a type of behaviorial isolation.

Sympatric speciation also occurs in plants. There are two closely related palm trees in Lord Howe Island near Australia. They are found in two areas of the island. The soil pH is different in these two areas. The palms do not interbreed. In this case sympatric speciation could have occurred due to competition for soil to grow on.

Another example occurs in three species of orchids. They live in the same rain forest. Each species has flowers that last only one day. The flowers must be pollinated on the same day. But each species flowers on different days. This prevents cross pollination. Temporal isolation happens when two or more species reproduce at different times.

Some flowers evolve to attract specific pollinators. An example would be the two different species of monkey flowers. Both species are found in the same area. The pink flowers are more open in structure. They are pollinated by bees. The bees like the wider floral tube to get to the nectar. The red flowers are narrower. They are pollinated by hummingbirds. The hummingbirds can reach nectar deep within the narrow tubes. This prevents cross pollination between the two different species of monkey flower.

Temporal isolation also occurs when in two related frog species, one species breeds earlier in the year than the other.

“And so there you have it,” said Professor Pickens as he ended his lesson. “I hope these examples help you understand sympatric speciation. A lot of the diversity in nature is due to this type of speciation.”