2.01 Species and Populations Flashcards
Biotic components
What is living in the system
Abiotic components
Non-living in a system
Species
Group of organisms that share characteristics and that can also interbreed to produce fertile offspring.
Problems arising when defining species
- Sometimes the male and female of the species look very different
- Sometimes different species look identical but can’t interbreed
- Organisms of different species can interbreed to create hybrids.
Niche
A match of species to a specific environmental condition where it can thrive. It involves where it lives, breeds, its food, activity patterns and interaction with other species.
Habitat
The environment (place) in which a species live, for example woodland habitat. Habitats contains a range of niches.
Spatial habitat
Every organisms own space in an ecosystem. The ecosystem also change due to the organisms presence. (E.g. Woodpecker in hollow tree)
Fundamental niche
Entire set of conditions under which a population could survive.
Realized niche
Is conditions actually used by given population after interactions with other species. Perhaps because of predation and/or competition.
When does competition happen related to niches?
The niche that an organism establishes is based on their adaptation or traits for survival. Organisms have to establish their own niche to survive. It is when two niches overlap that competition occurs.
Three main types of ecosystems
- Marine
- Freshwater
- Terrestrial
Marine systems
The sea, salt marshes, mangrove swamps, saline estuaries.
Freshwater systems
rivers and lakes
terrestrial systems
land based systems
Population
Group of organism of the same species that live in the same area at the same time.
Competition
Individuals in an ecosystem are in a competition for food, space and other resources. The organism best suited for the environment will survive and get the resources. Others have to adapt or die.
Intraspecific competition
Compete with members of ones own specie
Interspecific competition
Compete with members of other species
Predation
The interaction between species, where one is a predator and the other is a prey. The change in size of population is clear in this relationship.
Population size in relation to predation
Increase in predators—> Decrease in prey—> Decrease in predator—> Increase in prey—>
Herbivore
Animals that feed on plants
Parasitism
Relationship where parasite benefit from its host, which may suffer from parasite’s presence.
Mutualism
Relationship that benefits both organisms. E.g. union between fungus and algae Fungus absorbs minerals and protect algae from drying out. Algae photosynthesis and provides sugar for both.
Effects on organisms relationships summarized.
Benefit for both: Mutualism
Benefit for one and harm for one: Predation/parasitism
Harm for both: Competition
Limiting factor
Anything that constrains a population’s size and slows or stops it from growing. What a resource becomes when the demand for it is higher than its supply.
Carrying capacity
The number of individuals in a population that the resources can support in that environment
J-curve
Demonstrates a growth of population where it doesn’t slow down. it shows rapid exponential growth. First time entering a new habitat: Loads of resources = high birth rates and low death rates. The J-curve continues as long as the resources can provide it.
S-curve
Shows increase in population in the beginning and then how that slows down due to limiting factors. This is when the population becomes stabilized at a level the environment can support = the carrying capacity of the environment is reached.
Phases of the curves
- Exponential growth phase
No limiting factors so the population can just continue to grow. - Transition phase
Resources starts to become limited so the growth speed decreases - Plateau phase
Population is now stable at the carrying capacity.
Connect curves to feedback
J-curve = positive feedback, increase and increase
S- curve =negative feedback, increase and decrease
