Symbiosis
Species Interaction
Topic *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 trees
Image: 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)
Amensalism – Flowers will die, but we get
no benefit from it
Image: www.tidysflowers.com
Image: www.affordable-flowers.com
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
Image: www.for.gov.bc.ca
Interspecies –
Between two
different species
Intraspecies Within a certain
species
Which is this
picture?
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)