Ecology Flashcards
What is Ecology?
Ecology is the study of the interaction between organisms and with their physical environment
What is a population?
A population is a group of individuals of the same species living in the same area.
- The have the ability to interact and interbreed with each other
- Populations are variable in time. (The same population changes as organisms leave, enter, die, and are born)
What limits to growth and sustainability do populations face?
The limits to population growth are:
- Competition
- Predators
- Disease
- Pollution
- Available resources
What is a habitat?
A habitat is the physical area where a population lives. Every habitat is characterized by a particular range of:
- Temperature
- Humidity
- Soil
- Competitors
- Predators
- Other factors
What is a niche?
A niche of a population or species, is its functional role in the ecosystem
- Think of a niche as the organisms profession
- Plants turn CO2 into O2, they provide food for herbivores, they are players in the Nitrogen cycle, etc.
What is an ecosystem?
An ecosystem represents all organisms present in a particular area and their physical environment
- Composed of biotic (living) and abiotic (non-living) components (soil, wind, sunlight, etc).
- The ecosystems structure is determined by the biotic and abiotic components making it up
- A tropical rainforest is an ecosystem that possesses the greatest diversity of animal and plant life
- Coral reefs are ecosystems that are called “ocean rainforests” because they teem with so much life.
What is a community?
A community consists of groups of populations that are comprised of different species in the same area.
- For example: A woodland community could be comprised of a multitude of animals, plants, fungi, and bacteria
What is a dominant species?
A dominant species is the species that exerts control over the community.
- Can be any type of organism
- Dominant species usually:
- Possess greater biomass
- Found in greater numbers
What is diversity in a community?
Diversity in a community:
- The greater the species number and the more evenly the individuals are distributed, the greater will be the species diversity
What is a climax community?
A climax community is a stable community in which populations of animals or plants remain in equilibrium until destroyed by an event such as a fire or human interference.
- These are achieved through succession, the series of changes that ultimately give rise to a climax community
What is succession?
Succession is the progressive series of changes that ultimately give rise to a climax community
What are primary and secondary succession?
Primary succession
- Occurs when the terrain was without life, or almost so. The soil has not formed.
- A new volcanic island, lava flows, glacier retreats, sand dunes, etc
- Pioneer species such as mosses and lichens are usually the first to colonize an area.
- It takes a long time. Hundreds or even thousands of years
- The pioneer species set the stage for other organisms and usually set up their own demise.
Secondary Succession
- Series of community changes occur in disturbed areas that have not been totally stripped of their vegetation or soil
- An existing community has been cleared out by disturbances such as fire
- The process is faster than primary, because soil already exists.
- We eventually see the rise of a climax community in equilibrium following the disturbance
- Human’s are the biggest cause of secondary succession
NB for the DAT
Describe the current ozone problem?
Ozone problem:
- Since 1975 we are seeing a reduction in the ozone layer
- The invention of Chlorofluorocarbons is said to have contributed greatly to this.
- As CFCs break down they release halogen gases that can participate in radical reactions with the ozone in the atmosphere.
- One Cl2 molecule can participate in over 100,000 03 molecules in a radical chain reaction
- Without the ozone layer, we are subjected to increased radiation and all organisms suffer, because radiation causes DNA mutations
How did early earth become oxygen rich?
Early earth had no oxygen in its atmosphere, it became oxygen rich in the following ways:
- Since there was no ozone, radiation split H20 into H2 and O2. The lighter H2 escaped into space and O2 became trapped in the atmosphere
- The evolution of simple prokaryotic cyanobacteria, resulted in large amounts of CO2 being converted into O2
Describe the atmosphere of early earth
The atmosphere of early earth was a reducing atmosphere. It contained:
- CH4
- NH3
- CO2
- H2S (hydrogen sulfide)
- SO2 (sulfur dioxide)
- Water vapor
What is a greenhouse gas? What are the greenhouse gasses?
A greenhouse gas is a gas in the atmosphere that traps heat. Aside from water, most of these gasses take years to leave our atmosphere. Some of the major greenhouse gasses include:
- CH4
- N2O
- Hydrofluorocarbons
- Chlorofluorocarbons
- CO2
- Water vapor
What is global warming?
Global warming is the increase of the earths temperature due to the increased release of greenhouse gasses into the atmosphere.
What is continental drift?
Continental drift is the moving of the earth’s continents on tectonic plates over time
- The earth was believed to consist of one continent called pangea 250 million years ago. Over time, the tectonic plates of the earth moved to form our current continents
What is the mantle of the earth?
The earth’s mantle is the layer of earth between the crust and the core of the earth.
- It is about 1800 miles thick
What is the earth’s crust?
The earth’s crust is the topmost layer of earth that we live on.
- It consists of 47% oxygen and 28% silicon. (Lots of silicon dioxide (quartz))
