Chapter One: Intro to Ecology Flashcards
What is Ecology?
The scientific study of interactions between organisms and their environment.
What is the Scientific theory?
A collection of related hypotheses that have been rigorously and repeatedly tested via scientific method.
How is environmental science different from ecology?
The study of environmental science uses both natural and social sciences to study how the environment is affected by people. While ecology is just focused on natural sciences, meaning ecologists are not concerned with anything political regarding the environment.
What makes amphibians good biological indicators?
Their skin is permeable, their eggs have no protective shell, and they spend part of their life on land and part in water. Making them exposed to pollutants and UV in both environments.
What led scientists to begin studies on pacific tree frogs?
Observation in the field indicated that pacific tree frogs were experiencing deformities. Specifically, they were growing extra limbs due to cysts. They believed it was due to parasites.
Which parasite did they believe was causing deformities in tree frogs? And why?
The Ribeiroia ondatrae (a trematode flatworm). This was because this specific parasite is known to cause cysts that produced deformities.
Explain the first experiment done to prove the theory on the Ribeiroia parasite.
Scientists Ruth and Sessions brought tadpoles into a lab, where they implanted small glass beads to mimic the effects of Ribeiroia cysts. The test resulted in the frogs having deformities.
Explain the second experiment done to prove the theory on the Ribeiroia parasite.
Scientist Johnson and his colleagues performed a controlled experiment in the lab. Tadpoles were placed in containers and were randomly assigned 1 of 4 treatments. 0 (the control group), 16, 32, or 48 Ribeiroia parasites. They observed that as the number of parasites increased, fewer of the tadpoles survived, and more of the survivors had deformities than not.
Describe the life cycle of the Ribeiroia parasite.
The parasite starts in the SNAIL (first intermediate host), where it asexually reproduces free-swimming cercariae. The cercariae infect the TADPOLES (second intermediate host) and form cysts which result in leg deformities in the adult frog. The ADULT FROG is now more susceptible to predation due to the deformities. A BIRD (the definitive host) will then eat the deformed frog. Because the bird is a vertebrate creature, the parasite can mature to adulthood and reproduce sexually. It’s eggs are released in the bird’s feces and hatch. It then returns to the snail to repeat the cycle.
What other factor did scientists believe was causing the limb deformities in frogs?
Pesticides and fertilizers.
Describe the field experiment done to test the theory on pesticides.
John Kiesecker used 6 ponds. All of which had the Ribeiroia parasite but only 3 had pesticides. In each pond, wood frogs were placed in 6 different cages. In three cages, mesh lining that allowed the parasite to pass was used. While the other three had mesh to small for the parasite. The results showed that Ribeiroia was necessary for deformities to occur and when frogs were exposed, deformities were more common in ponds with pesticides.
What are factors influenced by humans that cause disease?
Population size, land development, climate factors, habitat degradation, abundance of vectors (ex: mosquitos)
What is spatial scales of study?
Small (mm, cm, m) and Large (tonnes and ha)
What is temporal scales of study?
Short (minutes, hours, days, etc.) and Long (centuries and millennia)
Definition of a Population.
A group of individuals of a single species that live in a particular area an interact.
