Unit 2: Species and Population Flashcards
Define Species
A group of organisms that share common characteristics and can interbreed to produce fertile offspring.
Define Population
A group of organisms of the same species living in the same area at the same time and which are able to interbreed.
Define Habitat
The environment in which a species usually lives.
Define Niche
Particular environment that offers the exact conditions that the species needs or has adapted to.
What are the Two Types of Niches?
1) Realized niche
2) Fundamental niche
Distinguish between the Realized and Fundamental Niche
Fundamental niche is the potential mode of existence of the species, the realized niche is the actual mode of existence of a species which results from adaptation.
Give an Example of a Niche
Rocky shore for barnacles in the North Atlantic: two species compete for habitat hence they establish in a realized niche.
What are Abiotic Factors?
The non-living components of an ecosystem.
What are Biotic Factors?
The living components of an ecosystem.
What are the Key Abiotic Factors of Marine Ecosystems?
- Salinity
- Temperature
- PH
- Dissolved oxygen
- Wave action
What are the Key Abiotic Factors of Freshwater Ecosystems?
- Turbidity
- PH
- Flow velocity
- Temperature
- Dissolved oxygen
What are the Key Abiotic Factors of Terrestrial Ecosystems?
- Temperature
- Light intensity
- Soil moisture
- Wind speed
- Soil particle size
- Soil mineral content
- Slope
- Drainage (porosity)
What are the Types of Population Interactions?
- Predation
- Herbivory
- Parasitism
- Mutualism
- Disease
- Competition
Distinguish between Interspecific and Intraspecific Competition
- Intraspecific: members of the same species
* Interspecific: different species for the same resources
What is Predation?
One species feeds on another which enhances fitness of predator but reduces fitness of prey (e.g. herbivory).
What is Parasitism?
The host provides a habitat and food for the bacteria, but in return, the bacteria cause disease in the host.
What is Mutualism?
A type of symbiotic relationship in which both species benefit from the relationship.
What is Competition?
The relationship between species that attempt to use the same limited resource.
What is Carrying Capacity?
The number of individuals in a population that the resources in the environment can support for an extended period.
What are Limiting Factors to Carrying Capacity?
- To plants: light, nutrients, water, CO2, temperature
* To animals: space, food, mates, nesting sites, water.
What are the Effects of Limiting Factors to a Population?
Will slow population growth as it approaches the carrying capacity of the system.
Distinguish between S- and J-curve
J-curves show exponential growth for populations establishing in a new habitat. S-curves show the establishment of a population into a new environment.
What are the Phases of Growth Curves?
1) Exponential growth phase
2) Transition phase
3) Plateau phase
Explain the Exponential Growth Phase
Limiting factors are not restricting the growth of a population.
Explain the Transition Phase
When limiting factors begin to affect the population restricting its growth.
Explain the Plateau Phase
Limiting factors restrict the population to its carrying capacity and changes in abiotic factors cause the population to remain stable around the carrying capacity level.
Define Community
A group of populations living and interacting with each other in a common habitat.
What is Photosynthesis? (+ Formula)
Transformation of light energy into the chemical energy of organic matter.
CO2 + H2O –> CHO + O2
What is Respiration? (+ Formula)
Breakdown of glucose using oxygen, releasing carbon dioxide, water and energy.
CHO + O2 –> CO2 + H2O
What is a Trophic Level?
The position an organism occupies in a food chain, or the position of a group of organisms in a community that occupy the same position in food chains.
Draw an Example of Food Web
(put picture from phone)
Distinguish between Food Chain and Food Web
A food chain shows the linear flow of nutrients and energy from one trophic level to another. A food web shows different food chains that are interconnected at many trophic levels.
What are the Trophic Levels?
1) Producer
2) Primary consumer
3) Secondary consumer
4) Tertiary consumer
Distinguish between Autotrophs and Heterotrophs
Autotrophs are organisms that are able to make their own food from raw materials and energy (aka producers). Heterotrophs are organisms that cannot make their own food (aka consumers) and hence feed on producers or other consumers.
What are Decomposers?
Organisms that feed on dead materials and recycle nutrients in the ecosystem.
What is Biomass?
The amount of biological matter in a living or recently living organism, measured in units of mass per unit area (gm^-2).
List the Three Types of Ecological Pyramids
1) Numbers
2) Biomass
3) Productivity
What does the Pyramid of Numbers Show?
Represents the number of organisms coexisting in an ecosystem; it is constructed by counting the number of organisms at each trophic level.
Evaluate the Pyramid of Numbers
Pro: show changes over time + overview of structure
Con: doesn’t consider size of org. or omnivores
What does the Pyramid of Biomass Show?
Shows the biological mass at each trophic level; biomass is estimated at a particular time, dry mass is multiplied by number of organism for each trophic level.
Evaluate the Pyramid of Biomass
Pro: considers size
Con: killing organisms for sampling + season variation
What does the Pyramid of Productivity Show?
Refer to the flow of energy through trophic levels and always show a decrease in energy along the food chain.
Evaluate the Pyramid of Productivity
Pro: can compare ecosystems + no inversion
Con: difficult to collect data + omnivores
What Unit of Measure is Used for Biomass?
gm^-2
What Unit of Measure is Used for Productivity?
gm^-2 yr^-1
How does Entropy Affect the Structure of an Ecological Pyramid?
The law states that when energy is transformed some of it is lost; in ecosystems the losses are due to respiration. On average, ecological efficiency is 10%; because it is so low each trophic level has a successively smaller energy pool therefore there can only be four/five trophic levels.
What is Bioaccumulation?
The build-up of a persistent pollutant within an organism or trophic level because it is not biodegradable.