SymbiosisSpecies InteractionTopic *1014
Ms. Morris
Symbiosis
• A close ecological relationship between the individuals of two (or more) different species
• Sometimes it benefits both species• Sometimes one species benefits at
the other's expense • Sometimes neither species benefits
Mutualism
• BOTH species benefits– One species gets food, while another
gets shelter– One species gets protection, while
another gets food
Mutualism – Ants and Acacia treesImage: www.discoverlife.org
Commensalism
• ONE species benefits, the other is unaffected– One species gets food, while the other is
not harmed or benefited– One species gets protection, while the
other is not harmed or benefited
Commensalism – Pseudoscorpions on a fly’s leg
Image: pick5.pick.uga.edu
Parasitism
• One species benefits, the other is harmed but not killed– One species gets food, while the other is
weakened• If the host species was killed, what
would happen to the parasite species?
Parasitism - Tomato hornworm is covered with cocoons of pupating braconid wasps
Image: www.cals.ncsu.edu
Neutralism
• Neither species is benefited or harmed– Both species live in the same
community, but do not interact
Neutralism – Both cacti and tarantulas live in the desert
Images: www.tetch.com
Amensalism
• One species is harmed, while the other is not affected– Forest fires – all species die, but no
species benefits– Floral industry – we cut flowers, the
flowers die, but we don’t get a real benefit (other than it looks pretty)
Image: www.affordable-flowers.com Image: www.tidysflowers.com
Amensalism – Flowers will die, but we get no benefit from it
Competition
• Both species are harmed– Species fight for food– Organisms within a species fight for a
mate– comp.mov
Competition – Evergreen Trees are competing for light and nutrients
Interspecies – Between two different species
Intraspecies - Within a certain species
Which is this picture?
Image: www.for.gov.bc.ca
Questions
• What is the difference between parasitism and amensalism?
• Why don’t parasites let their hosts die?• What kind of relationship do ants and
acacia trees have?• Why doesn’t a competitive relationship
benefit any species?• Hand this in to Ms. Morris by the
end of the day!!! (10 points)