14.2 community interactions key concept organisms interact as individuals and as populations
TRANSCRIPT
14.2 Community Interactions
Competition and predation are two important ways inwhich organisms interact.
• Competition occurs when two organisms fight for thesame limited resource.– Food– Water– Shelter– Mates
• How does cooperation
and competition among
organisms differ from
human cooperation and
competition?
14.2 Community Interactions
Interspecific competition
• Occurs between two different species, even though they have different niches
14.2 Community Interactions
Symbiosis - A close relationship between 2 or more organisms of different species living together
14.2 Community Interactions
• There are three major types of symbiotic relationships.
1. Mutualism: both organisms benefit
14.2 Community Interactions
Lesser long nosed bat
• Bat pollinates cactus in spring as they feed on nectar
• In summer eat fruit and spread indigestible seeds when they pooh!
14.2 Community Interactions
2. Commensalism: one organism benefits, the other is unharmed
Human Our eyelashes are home to tiny mitesthat feast on oil secretions and dead skin. Without harming us, up to 20 mites may be living in one eyelash follicle.
Demodicids Eyelash mites find all they need to survive in the tiny folliclesof eyelashes. Magnified here 225 times, these creatures measure 0.4 mm in length and can be seen only with a microscope.
+
Organism benefits+
Ø
Ø Organism is not affected
Commensalism
• There are three major types of symbiotic relationships.
14.2 Community Interactions
3. Parasitism: one organism benefits, the other is harmed
• There are three major types of symbiotic relationships.
Organism benefits0
_
Organism is not affected
Hornworm caterpillarThe host hornworm will eventually die as its organs are consumedby wasp larvae.
Braconid waspBraconid larvae feed on their host and release themselves shortly before reachingthe pupae stage of development.
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Parasitism
+
0
14.2 Community Interactions
• There are three major types of symbiotic relationships.– 3. Parasitism meet their needs as ectoparasites
(such as leeches) and endopaasites (such as hookworms)