Community Interactions Flashcards
Trophic levels
Feeding levels
The main trophic levels in an ecosystem
- Producers
- Consumers
- Decomposers
Predation
A feeding interaction where a predator eats the prey
Predator adaptation examples
- Agile
- Speedy
- Good sense of sight and smell
- Predator dentition and claws
- Camouflage
Example prey adaptations
- Herding
- Camoflage
- Warning colouration
- Poisonous secretions
Predator prey relationships
- Similar fluctuations in numbers since predators depend on prey for food
- Predators control numbers of prey
- Prey determine numbers of predators
- A density dependent factor
Predator-prey graph
- A graph showing the interaction
- General pattern is that there is a delay in response of predator numbers to increase or decrease
- Generally fewer number of predators than prey
Features making lions succesful predators
- Powerful and agile
- Sharp teeth and claws
- Camouflage
Typical prey of lions
- Wildebeest
- Zebra
- Gemsbok
- Kudu
- Warthog
Lion biomes
- Savannah
- Grassland
- Bushveld
Hunting strategy of lions
- Females predominant hunters
- Males help with bigger prey
- Hunt usually at night
- Ambush as a group (stalk till 30m away)
Hunting strategy of crocodiles
- Drift quietly and unseen with submerged body
- Ambush using high speed over short distances
- Prey grasped with jaws and drowned
- Chunks of carcass eaten as these rot underwater
Top predators
Animals at the top of the food chain with few or no natural predators
Competition
Occurs when individuals compete for the same limited resource
Ecological niche
- Each species has its own particular role in an environment
- This has a limiting effect on competition between different species
Competition between individuals of the same species
Intraspecific competition
Examples of intraspecific competition
- Yellowood trees in the same grove of forest compete for light
- Piglets feeding from a sow compete for milk
Competition between individual of different species
Interspecific competition
Competition a density dependent or density independent factor?
- Density dependent
- The more individuals in a particular area, the more limited the available resources, the more competition there is
Examples of interspecific competition
- Different species of tree competing for light in a forest
- Hyena and lions competing for food as they feed on a dead zebra
Competitive exclusion
- In a stable ecosystem
- Two species will not be able to occupy the same niche for an extended time
- One will outcompete the other
- (Known as Gause’s Law)
Organism originally used to illustrate Competitive Exclusion
Paramecium sp.
(Kingdom Protista)
Resource partitioning
- Two or more species can co-exist in the same habitat
- because they occupy different specialised niches
- E.g. different feeding times
- E.g. Different parts of the habitat
Symbiosis
A close and often long term interaction between two different species
Mutualism
Symbiotic relationship between two species where both benefit
Example mutualisms
- Bees and flowers (pollination)
- Honeyguide bird and humans (honey hunting)
Commensalism
A symbiotic relationship between two species where one benefits and the other is unaffected
Examples of commensalism
- Birds nesting in trees
- Plant epiphytes on tree branches
- Remora suckerfish and sharks
Parasitism
A symbiotic relationship between two species where one benefits and the other is harmed
Parasites living outside the host organism
Ectoparasites
Parasites living inside the host organism
Endoparasites
Example ectoparasites
- Ticks on a dog
- Aphids on a rosebush
- Dodder on various plants
Example endoparasites
- Malaria
- Bilharzia
