Selection Pressures Flashcards
What is an ecosystem?
A community of organisms living in a given area that interact with each other and their environment.
List four examples of ecosystems.
Rainforest, human intestines, sand dunes, alpine areas, etc.
What are the three levels of biodiversity?
Genetic diversity, species diversity, ecosystem diversity.
What is genetic diversity?
The variety of genes found within a species.
What is species diversity?
The variety of species found within a habitat/region.
What is ecosystem diversity?
The variety of ecosystems found within a given area.
What are positive selection pressures?
A factor that increases the likelihood of a particular species (or variations within a species) to survive and reproduce.
What are negative selection pressures?
A factor that decreases the likelihood of a particular species (or variations within a species) to survive and reproduce.
What is biodiversity?
The variations found within the genetics, species, and ecosystems of living things.
What is an abiotic selection pressure?
A selection pressure that involves non-living factors.
What is a biotic selection pressure?
A selection pressure that involves living factors.
List three examples of abiotic selection pressures.
Air temperature, soil pH, availability of water.
List three examples of biotic selection pressures.
Availability of food, competition for territory, ability to find a mate.
What type of selection pressure is loss of habitat?
A negative, biotic selection pressure.
Explain how limited food supplies have impacted the evolution of the coconut crab (Birgus latro).
They have evolved to be able to climb coconut trees and have claws suited to opening coconuts.
How do high populations of crown-of-thorns starfish act as a selection pressure for coral populations in the GBR?
COTS are predators of coral, and therefore act as a negative, biotic selection pressure for coral.
Identify the positive abiotic selection pressure aiding population growth of COTS.
High-nutrient run-off from agricultural areas.
What is the formula for abundance?
Abundance = number of individuals/size of area
What does the term “abundance” refer to?
The number of individuals of a given species living in a given area.
How has overfishing of the giant triton snail acted as a selection pressure on COTS?
It has acted as a positive biotic selection pressure for the COTS, as triton snails are their main predator.
What selection pressure caused species (such as Ficus watkinsania) to exist as “strangler figs”?
Lack of light on the forest floor for fig saplings.
Are toxic pesticides an abiotic or biotic selection pressure?
Abiotic.
What is the “goal of a species”?
To survive to reproduce.
