Week 10: Questions Flashcards
Case Study: The Near Extinction of Kirtland’s Warbler: You can see from the images of the Kirtland’s Warbler that it is a very noticeable bird. It is very colourful and has a distinctive song. Do you think that if the Kirtland’s Warbler was a dull brown bird with a song that was hard to separate from another species, would we have noticed its declining population and taken steps to preserve its habitat? Explain your answer.
Because Kirtland’s Warbler is a more rare population, it became more noticeable that their population was endangered. If they had a more common colour and song, their decreasing numbers may not have been observed
In many science fiction stories, creatures from other planets invade Earth and attack humans. Do you think that an organism from another planet would be able to successfully survive on Earth? Explain your answer.
It would not be able to successfully survive on earth. Because they have most likely adapted to the conditions of their own environment, there would be a big difference for them to adapt to by moving to a different planet as these conditions will be drastically different, therefore they would not survive
Habitat adaptation example
Because kangaroo rats live in a desert habitat, achieving a balance between water input and output is difficult
They have efficient kidneys that require little water to eliminate toxic substances in their urine
They are nocturnal to help with evaporation loss (through the nose and lungs)
They metabolize food by digesting food by oxidizing it (oxygen they breathe is combined with hydrogen atoms in food to produce water)
Describe the behaviour of a male americana damselfly when a male of H. titia was flown into its territory if:
H. americana is normally the only species in that location
- The americana did not distinguish between intruders with black ink on wings versus intruders with it
Both species are normally present in that location
- The americana respond less aggressively to intruders with blackened wings
Discuss the reasons why these behaviours occur. If two species occupy the same niche, what can happen to avoid one of them going extinct?
Occurs because of agonistic character displacement (caused by direct competition), as they see flies with the same characteristics as competition
They can undergo character displacement so that they change and do not have to engage in competition, therefore don’t go extinct
How can competition be avoided?
One competitor can win by driving the other to extinction
One or both species can change so that they no longer use the same resource
Cheetahs eat gazelles. Both can run very fast. This is an example of what phenomenon we see in evolution of species in an exploitative relationship?
An evolutionary arms race because the cheetahs are trying to exploit the gazelles, but the gazelles are attempting to avoid the exploitation
Do you think that the National Park Service should move more wolves to Isle Royale? Explain your answer
Yes because without doing so, the population will die out and the moose population will increase, leading to a decrease in shrubbery on Isle Royale
What are the effects observed of exploitation?
Population cycles of both species are linked (each population increase and decreases regularly overtime)
Example: predator and prey relationship (1. as the number of predators increases, they exploit their prey 2. As the number of prey increases, there is more food for predators so their population increases, exploiting the prey 3. As the number of prey increases, they exploit their own food source and become an exploiter)
An evolutionary “arms race” (the exploited species develop adaptations to avoid being exploited, and the expoiter develops adaptations to continue exploitation)
If you are a pollinator specializing in just one species of plant, you have a reliable source of food, but what is the risk?
If the species of plants goes extinct, I will be left without a food source and will ultimately die out as well
What do we call the species that end up competing most successfully against humans?
Pests
Sometimes it’s possible to use one living species against a pest species. In a local example, homeowners introduce nematodes to their lawns to kill the European chafer beetle, which feeds on the grass roots. What is this type of defense called?
Biological control (an approach to controlling pests by introducing its predators into an area)
Trophic pyramid
Primary producer: plants capture sunlight in the form of chemicals, sugars and starches
Plants use these chemicals to derive their own metabolism
Primary consumer: herbivores who eat the plants
The energy and nutrients from the plant are transferred to the herbivore
Secondary consumer: carnivores who eat herbivores
The energy and nutrients from the herbivore are transferred to the carnivore
Decomposers: cause dead bodies to rot
Ultimate level of any food web
Biogeochemical cycles
Processes that move matter among the four reservoirs (biosphere, atmosphere, hydrosphere, lithosphere)
Carbon cycle: the movement of carbon throughout the ecosystem
Drivers of this cycle are photosynthesis (remove carbon dioxide from the atmosphere and convert it to energy rich carbohydrates) and respiration (organisms break down carbon compounds and release carbon dioxide back into the air)
Oxygen cycle: the movement of oxygen throughout the ecosystem
Oxygen is added to the atmosphere through photosynthesis and removed by respiration
Nitrogen cycle: the movement of nitrogen throughout the ecosystem
Soil bacteria make nitrogen available (step 1: some bacteria can breathe in gaseous nitrogen in the soil and capture it in nongaseous chemicals, step 2: bacteria convert compounds to nitrate, which plants can use and therefore move through the food web)
At what trophic level would you put a cow?
A primary consumer because it is a herbivore who consumes plants
