Biosphere (1) Flashcards
Define ecology.
Ecology is the scientific study of the interactions of organisms and the environment.
Define biosphere.
The biosphere is all of Earth that is inhabited by life
-extends from the atmosphere to the depths of the oceans
-although the biosphere is vast, it is also finite.
Organisms can potentially be affected by many different variables, grouped into two major types. What are these factors?
1. Biotic factors include all of the organisms in an area, the living component of the environment.
2. Abiotic factors are the environment’s nonliving component, the physical and chemical factors
Define a habitat.
An organism’s habitat includes the biotic and abiotic factors present in its surroundings.
How would an organism be considered successful?
To be successful, organisms must be adapted to the abiotic factors present in their environments.
What are the abiotic factors?
Major factors include
-energy sources
-temperature
-the presence of water
-inorganic nutrients
-other aquatic and terrestrial factors.
Lack of sunlight is the most important factor limiting plant growth in terrestrial ecosystems. True or false?
False. Lack of sunlight is rarely the most important factor limiting plant growth for terrestrial ecosystems.
In many aquatic environments, however, light is not uniformly available
Why does most of the photosynthesis only occur at the surface of the water?
Microorganisms and suspended particles absorb light and prevent it from penetrating beyond certain depths. As a result, most photosynthesis occurs near the water’s surface.
How do organisms in dark environments i.e. caves get their energy source? Explain how sulfur bacteria gain their energy source.
In dark environments such as caves or hydrothermal vents, bacteria that extract energy from inorganic chemicals power ecosystems.
Sulfur bacteria perform this function in hydrothermal vent communities.
Some of the animals there feed directly on the sulfur bacteria; others derive nutrition from bacteria living inside their bodies
Why is temperature an important abiotic factor?
Temperature is an important abiotic factor because of its effect on metabolism.
Few organisms can maintain a sufficiently active metabolism at temperatures close to 0°C, and temperatures above 45°C destroy the enzymes of most organisms.
Explain how birds and mammals adapt to the temperature.
Mammals and birds can remain considerably warmer than their surroundings and can be active at a fairly wide range of temperatures.
Explain the effect of temperature on amphibians and reptiles.
Amphibians and reptiles, which gain most of their warmth by absorbing heat from their surroundings, have a more limited distribution.
For terrestrial organisms, ______ is a major danger.
For terrestrial organisms, dehydration is a major danger.
What were the evolutionary adaptations that enabled plants and vertebrates to be successful on land?
Watertight coverings (cuticles) were key evolutionary adaptations enabling plants and vertebrates to be successful on land.
Aquatic organisms are surrounded by water; their problem is ___________. Explain.
Aquatic organisms are surrounded by water; their problem is solute concentration.
Freshwater organisms live in a hypotonic (minimal solute) medium, while the environment of marine organisms is hypertonic (surplus of solute). Animals maintain fluid balance by a variety of mechanisms
