What is a species?
A group of organisms sharing common characteristics that can be interbred to produce offspring that can interbreed.
What are the limitations of the species concept?
- Doesn’t account for asexually reproducing organisms.
- Doesn’t classify species in extinct populations.
- Doesn’t identify whether isolated populations belong to the same species.
What is environment?
The external surroundings that affect species’ survival and development.
What are abiotic factors?
- Salinity (Non-living, physical factors)
What are biotic factors?
What is a habitat?
The environment in which the species lives.
What is a Niche?
Where, when and how a species lives, what it feeds on, how it interacts with its habitat and other organisms etc.
A niche defines a species.
Species can have overlapping niches, which leads to increased competition, but not the same niche. A particular set of biotic and abiotic factors a population responds to.
What is fundamental and realized niche?
- Fundamental niche is the full range of conditions in which a species can survive and reproduce.
- Realized Niche is the actual range of conditions. (limited by interactions with other species)
Range of intolerance, physiological stress.
What are biotic factors?
Predation, Symbiosis, Parasitism, Herbivory, Disease, Competition
- An animal hunts and eats another animal, negative feedback cycle,
- Also kinda good for prey because it creates a superior breeding pool
- What is Herbivory?
- An area with a more abundant plant resource has a larger carrying capacity for the herbivore
What are ectoparasites?
Lice, ticks, mites
What are endoparasites?
What are pathogens?
Things that create disease
What is intraspecific and interspecific competition?
- Inter is between different species
- Intra is within a species
- When resources decrease intra increases, when niches overlap, inter increases.
The stronger competitor will…
Reduce the carrying capacity for the other’s environment
What is a population?
A group of organisms of the same species living in the same area at the same time.
S population curve?
- Due to limited resources and limiting factors, the rate of growth slows down and fluctuates when the carrying capacity is reached. Has 4 phases:
- 1.Lag phase: a small number of indivudals colonize the area nad have a small number of offspring
- 2.Exponential growth phase: limiting factors are not restricting the rate of growth, no disease no predation, good temperature, good rainfall
- 3.Transitional phase: limiting factors begin to affect the population and increased competition, disease and predation limit the rate of growth
- 4.Stationary phase: population growth stabilizes and fluctuates due to abiotic and biotic factors.
What is carrying capacity?
Maximum number of individuals of a species that can be sustained by an environment.
What is the J population curve?
- Limiting factors do not restrict the rate of growth
- Usually with species with rapid reproduction and minimal parental care like insects and shit
- Populations tend to crash due to overused food resources, change in abiotic factors, disease etc.)
What are limiting factors?
Factors that limit the distribution or number of a particular population.
What are density dependent limiting factors?
Factors that are affected by the population size of the species (food, water supply, predation, disease)
What are density independent limiting factors?
- Not related to population density
- Natural disasters
What is a community?
Many species living together.
What is an ecosystem?
A community and the physical environment it interacts with.
What is a trophic level?
The position that an organism occupies in a food chain.
What is an autotroph?
Typically plants or algae that produce their own food.
- What is the second law of thermodynamics?
- Energy and biomass decrease along the food chain due to loss to heat.
What is bioaccumulation?
The buildup of nonbiodegradable pollutants within an organism or trophic level.
What is biomagnification?
The increase in the concentration of nonbiodegradable pollutants along the food chain.
What is the unit of storage:
g/m2 or j/m2
Respiration/ photosynthesis equation:
What is respiration?
Chemical energy to kinetic energy and heat.
What is a storage?
Standing stock of energy or a mass at a specific point in time.
What is a flow?
A flow of energy or mass over a period of time.
The total biomass or energy gained by producers in a specific area in a specific amount of time.
The total biomass or energy gained by consumers in a specific area in a specifc amount of time.
Net Primary productivity:
Just deduct respiration.
Why do heterotrophs lose more energy than autotrohps?
- More complex systems
- hunting , moving
- Complex reproduction
- Maintaining body temperature
How to calculate efficiency?
Gross production/ energy invested x 100
What is Gross Secondary Production?
- Total gain in biomass gained by consumers through absorption in a specific amount of time in a specific area
- Food eaten- fecal loss
- NSP is respiration deducted.
Why is fecal loss higher in herbivores?
Cellulose is harder to digest
What is the albedo effect?
- Is the measure of reflectivity of a surface
- Higher albedo with ice and snow, lower with water
Why is not all of sunlight energy is used?
- Reflection from clouds
- Absorption by clouds
- Reflection from the surface of the earth
- Absorption by atmospheric levels and dust
Explain Pyramid of Numbers
- Number of each individual at each trophic level
- Good for comparing populations through time
Explain Pyramid of Biomass:
- Biological mass of the standing stock at each trophic level at a specific point in time
- May be misleading due to seasonal change and is hard to measure with many assumptions but good for comparing seasons
- g/m2 or j/m2
Explain Pyramid of Productivity:
- Flow of energy through each trophic level of a foodchain over a period of time
- Always pyramid due to second law of thermodynamics and directly comparable (no seasonal change shit)
Give ecosystem example:
- Pine-pine borer-salamander-snake
- Phytoplankton-starfish-flatfish-harp seals
Why are top carnivores vulnerable?
- Effected by all trophic levels
- Biomagnification and bioaccumulation
What are the implications of a pyramid structure?
Limited food chain due to second law of thermodynamics
- Detrivores: larger organisms that break the leftovers into smaller pieces for future decomposition
- Saprotrophs: fungi and soil bacteria
Explain different kinds of plants:
- Hydrophytes: water plants
- Mesophytes: normal plants
- Xerophytes: cacti and stuff that store water
What is sustainable yield?
- The rate of increse in biomass thast can be exploited without depleteing the original stock or its potential for replenishment
- Equal or lower to their natural productivity
What is maximum sustainable yield?
- The maximum of a given resource such that the stock does not decline over time.
- Equivalent to net primary or secondary production
j/m2yr or g/m2yr
What are the reasons for high net productivity in an ecosystem?
- Higher primary productivity leads to higher energy investment in all tropic layers of the ecosystem
- Efficient energy transfer results in more energy to use
- Both result in longer food chains which means higher productivity