Module 4 Flashcards
What are benthic and pelagic abiotic factors?
Pelagic – Communities of free swimming and floating organisms.
Benthic – Communities that still live in the deep ocean.
What are biotic factors that effect organisms?
-Predation
-Competition
-Symbiosis – mutualism, commensalism and parasitism
These interactions can be positive, negative or neutral.
What is predation?
Predator-prey relationships is a type of feeding relationship where the predators
obtains its food by killing another animal (prey).
This relationship will often occur in a population that causes fluctuations during
different periods throughout the year and may coincide with;
- Seasons
- Breeding cycles (for both predator and prey)
- Variations in predator that increase/decrease kill rate
- Variations in prey that increase/decrease escape rate
- Other environmental pressures
What is competition between two organisms?
Species often compete for a number of reasons. These include;
- Food
- Shelter
- Mates
The competition stems from the requirements of resources that are in a limited
supply.
Organisms can compete;
- Within a species (intraspecific competition)
- Between species (interspecific competition)
What is allelopathy?
Some organisms secrete chemicals that can be detrimental or beneficial to another
organism.
This is often used to keep other organisms away in order to prevent competition
for resources.
What is symbiosis?
Symbiosis is the term used for the interaction between two organisms that live in close
relation to each other. This is always beneficial for at least one of them.
Symbiosis where the organisms can only exist together is known as an obligate
relationship. E.g. Lichen is a mix of fungi, algae and cyanobacteria.
When two organisms can survive independently but interact for their benefit are known
as facultative relationships. E.g. Ants protect aphids who produce sugary fluid that the
ants eat.
What are the three types of symbiosis?
Mutualism – Both organisms benefit (+/+)
Commensalism – One benefits and the other is unaffected (+/0)
Parasitism – One benefits and the other suffers non-lethally (+/-)
What is mutalism?
Mutualism is observed in coral.
its two interactions include;
1. Coral gives the algae a home as well as waste products that
the algae can use to photosynthesise and reproduce.
2. The coral uses the oxygen and organic molecules produced
by the algae to grow, reproduce and grow more skeleton.
What is commensalism?
Commensalism is observed in epiphytes, such as
mosses, small ferns and orchids.
Epiphytes are a non-parasitic plant that grow on
another plant for support.
Epiphytes grow on large trees and use run-off water
from rain to dissolve nutrients. It also allows it to have
more access to sunlight.
What are the types of parasitism?
Ectoparasite – The parasite exists on the outside of the organism. E.g. fleas, ticks
etc
Endoparasites – The parasite exists inside of the organism. E.g. Tapeworm,
roundworm etc
Macroparasites – Visible to the naked eye.
Microparasites – Invisible to the naked eye
What is an ecological niche?
The part of the environment that an organism occupies is called a ‘niche’.
A niche includes all of the resources, both biotic and abiotic, that the species uses to
survive.
No two species can occupy the same niche. This is known as the “competitive exclusion
principle”.
What are the consequences of predation?
Predators affect the distribution and abundance of their prey and is one of the
ways nature controls populations.
Population may remain stable if it can reproduce at a rate equal to their predation
rate.
Predator-prey population often fluctuate with each other.
What are the consequences of competition?
Competition for resources affects reproduction and survival rates.
Population fluctuates directly with resource availability.
Some species compete more effectively than others and can sometimes results in
complete extinction of a species within an ecosystem.
Competition for resources affects reproduction and survival rates.
Population fluctuates directly with resource availability.
Some species compete more effectively than others and can sometimes results in
complete extinction of a species within an ecosystem.
What are the consequences of symbiosis?
- Increase biodiversity
- The development of new species from integration of their genetic materials
(symbiogenesis) - Yield new capabilities for organisms, increasing fitness.
What are the consequences of disease?
Disease is any process that adversely affects the normal functioning of tissues in a
living organism.
Diseases often have the largest effect of the balance of food webs with pathogens
affecting one species causing a change in other specie in the same food web.
