Population Interactions Section 5.2- How do different species live with each other?
An Organism’s Niche The unique role of a species within an ecosystem is its niche. A niche includes the physical home (habitat), the abiotic and biotic factors necessary for survival, and ALL of the species’ interactions with other organisms. Basically a niche is an organism’s pattern of use of its habitat.
Symbiotic Relationships • SYMBIOSIS is the interaction between 2 or more different organisms living together in a close long-term relationship. • Example= lichens (fungi and algae) • Lichens are the pioneer species of primary succession.
What is a symbiotic relationship? • Relationship that exists between organisms that live in a community • Often occurs because niches overlap • They result due to the sharing of natural resources
Five (5) Ways Species Interact • Competition • Predation • Parasitism • Mutualism • Commensalism
1. COMPETITION • Relationship in which different individuals or populations attempt to use the same limited resource • Each individual has less access to the resource, therefore BOTH are harmed • Occur both within (intracompetition) species and between species (intercompetition) Species A Species B
2. PREDATION • One organism feeds on another by killing it • The organism that is fed upon is called the “prey” • Prey have developed mechanisms to help avoid or defend against predators (great sense of smell) • Predators have developed mechanisms making them better hunters (camoflauge) • One organism is harmed, the other benefits Prey Predator
f) Herbivory Specialized form of predation Herbivores feed on plants Technically doesn’t kill the plant- it affects their growth and reproduction Plants have natural defenses- thorns, spines, chemicals
Predator- Prey Graph 1. Populations cycle between predators and prey. 2. If the number of prey decreases, the number of predators eventually decreases.
3. PARASITISM • Relationship where an organism (A) lives in or on another organism (B) and feeds on that organism (B) • The organism the parasite takes its nourishment from is called the “host” • Somewhat like predators BUT they don’t kill their host, they just make the host sick • Species A benefits, Species B is harmed Host (B) Parasite (A)
4. MUTUALISM • When one species depends upon another species for survival • BOTH species benefit from the relationship • Close relationship, sometimes neither species can exist without the other • Often coevolution occurs.
5. COMMENSALISM • Relationship where one species benefits and the other species is neither harmed nor benefits Example: robin’s (bird) nest in a tree Bird Tree
Video examples… • Competition: Giraffe Battle | Africa – YouTube • Parasitism: Body Invaders – YouTube • Predation: Wolf Hunting Tactics – YouTube
Video examples… Monsters inside me https://www.youtube.com/watch?v=SU3SDrI0BTo&list=PLb-or5XGClNe_8DRaPFtd0hrMv0dP_tV-&index=14