Ecology and Communities Flashcards
What is a community?
A community is a group of populations of different species living in a close proximity, thus they can interact
What is a niche?
A niche is the sum total of an organism’s interaction with biotic and abiotic resources of it’s environment.
What is the difference between a fundamental niche and a realized niche?
A fundamental niche:
- The theoretical niche where no limiting factors are present.
- No competitors, no disease, no parasites, no predators
A realized niche:
- The niche that is actually organized by the organism
- For example, if a predator is present, the organism will no longer feed in that area.
- Thus differs from the fundamental niche
NB for the DAT
What is symbiosis?
Symbiosis is the ecological relationship between different species of organisms living in the same community
- Can be harmful, beneficial, or neutral
What is mutualism?
Mutualism is a symbiotic relationship where both organisms benefit
- Bacteria make vitamin K while living in the human intestine
- Pollinators and flowering plants
- yucca moth and yucca plant
What is commensalism?
Commensalism is a symbiotic relationship where one organism benefits and the other organism is neither harmed nor helped.
- Bird using a tree as a nesting site (tree gets nothing in return, but is not harmed)
- A plant like a fern uses another for shade
- Barnacles living on a whale. Doesn’t harm the whale, but barnacles get benefit of constant water filtration for food.
What is parasitism?
Parasitism is a symbiotic relationship where on organism benefits, while the other organism is harmed.
- Blood fluke infects a human and causes enlargement of the liver and spleen in addition to other disorders
- Athletes foot fungus
What is interspecific competition?
Interspecific competition is when individuals of different species compete for a resource that they depend on for their growth and survival. (Fox and lynx compete with each other for prey). There are two types:
- Interference competition: Kill competitors or chase them away from a resource.
- Exploitation competition: Use up a resource before anything else can
What is interference competition?
Interference competition is a type of interspecific competition where competitors kill or chase each other away from a resource
What is exploitation competition?
Exploitation competition is a type of interspecific competition where competitors attempt to use all of a resource before the other organism does.
- Both have equal access, but one uses it at a faster rate
What is competitive exclusion?
Competitive exclusion occurs when two or more species are fighting over the same resource.
- Both species can’t coexist
- One will have a slight advantage that will cause the other one to be eliminated
- If niches of species are the same, two species will be unable to coexist permanently in a community
What is resource partitioning?
Resource partitioning occurs when organisms in the same niche branch out to form different niches for survival. Examples:
- Three plants living in the same field exploit a different part of the soil. Each is able to survive, hence they coexist
- Three types of lizards, live in close proximity and have competition of resources. One likes the sun, one likes the shade, and one likes high places. There is a possibility that all three could survive, given they stay in the areas only they like.
- The fundamental niche is different than their realized niche.
What is predation?
Predation is when an organism gets its nutrients from killing and consuming another organism
- When predators can prevent their prey from overshooting its carrying capacity, then a stable coexistence can occur.
- It is often the most important factor that determines population size. It is regarded as a powerful agent of natural selection
- Predators help in population control
What is a parasite?
A parasite obtains food from the host, which it might kill, or might not.
- The parasite will live in or on the host for a long time
- Parasitism could be considered a form of predation
What are the characteristics of a predator?
Natural selection favors the most efficient predator. Many predators have the following:
- Acute senses
- Teeth or fangs
- Stingers
- Claws
- Fast to move
- Agile
- Thick and strong structures like beaks and bills
What are some defensive adaptations seen by prey animals?
Prey animals can exhibit the following adaptations:
- Morphological features
- Chemicals
- Concealment and camouflage
- Aposematic signals
- Mimicry
What are the morphological features that are exhibited by prey?
Morphological features exhibited by prey can help them avoid predation. They include:
- Pill bugs and armadillos rolling into a ball
- Porcupine spikes
- Lizards breaking off their tail
- Hermit crabs carry sea anemones on their back
How do prey animals use chemicals to fend off predators?
Prey animals use chemicals to fend off predators in the following ways:
- Plants fend off predators with toxins including: Nicotine, caffeine, morphine, cocaine, strychnine, and quinine. These alkaloids have pharmacological effects on bothe humans and animals
- Some alkaloids inactivate enzymes, others disrupt DNA repair mechanisms.
What are aposematic signals?
Aposematic signals are signals to predators that an organism is poisonous.
- Aposematic coloration: Many unpalatable or poisonous organisms display bright colors
- Skunks striped tails, colorful frogs and insects, etc
What is mimicry?
Mimicry is when a species has the same or similar appearance as another. There are two types
- Batesian mimicry: Deception
- Mullerian mimicry: Part of the cool poisonous gang with gang colors to match
What is Batesian mimicry?
Batesian mimicry is where we see deception.
- A harmless organism “pretends” it’s dangerous by looking like an organism that is poisonous and dangerous
- A harmless fly resembles a hornet
What is Mullerian mimicry?
Mullerian mimicry is where we see similar types of poisonous or dangerous organisms with the same or similar appearance.
- Ex: Bees and hornets with black and yellow striping
What is species diversity?
Species diversity refers to the variety of organisms which are different that make up the community and includes:
- richness: number of different species
- evenness: the relative species abundance
The more species you have and the more evenly distributed they are, the greater the species diversity
What is a food chain?
A food chain is the sequence of organisms in which energy moves
- Contains a primary producer: ex: grass
- Contains a primary consumer: grasshopper
- Contains a secondary consumer: rat
- Contains a tertiary consumer: snake
- Contains a quaternary consumer: hawk
- And so on, until the apex predator is shown
