Who are our friends? - University of Southern Mississippiocean.otr.usm.edu/~w777157/S2010Lec13_Coexistence_online.pdf · Honey Bees Pollinators of agriculture (30%) - fruit trees,
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13. Coexistence
Who are our friends?
Species
http://neatorama.cachefly.net/images/2008-12/species-population-size.jpg
About 1,500,000 species identified
Insects – 750,000
Other Arthropods – 123,000
ArthropodsMeans Jointed appendages
First repetitive body segments (adaptation)
Dominant life on Earth based on species
Exoskeleton (molt to get larger)
Live in all habitats
Arthropod Classes
Trilobites:
extinct
Crustaceans
Chelicerates
Myriapods
Hexapods (insects)
65% (1.5 million species)
crabs, shrimp, lobsters
spiders, scorpions, ticks, mites
centipedes, millipedes
Hexapoda: Insect Species
Beetles: 300,000
1of 5 species on Earth!
Butterflies & Moths: 170,000
Flies: 120,000
Bees, Wasps, & Ants: 110,000
Grasshoppers: 20,000
Dragonflies: 5,000
Preying mantis: 2,000
Insect Body Plan
Body Segments
Head: senses
Thorax: movement
Abdomen: organs,
reproduction
Appendages
Antennae
Legs
Wings
Adaptation of these structures has led to the
diversity of insect forms
Insect importanceDecomposition of dead organic material
Products
silkhoney shellac
http://www.radiomuseum.org
/forumdata/upload/FlakeShell
ac_Finish.jpg
Food source for animals
birds
reptiles
arthropods (spiders)
mammals (humans)
Pollinators
Pests and disease
Co-evolution of plants and insects
Coevolution:
adaptation of two
species to each
other for their
mutual survival
Certain flowers and
insects have co-
evolved
Explains the
diversity of forms
plants and insects
Darwin’s Hawkmoth
Charles Darwin (in 1822)
Comet orchid with 12” nectar
tube
Predicted there must be an
insect with a 12” tongue
http://faculty.washingt
on.edu/jrw/110/darorc
h.JPG
Darwin’s Hawkmoth
Co-evolution
Orchid tube is too long:
moth starves
orchid dies off
Orchid tube is too short:
moth does not pollinate
orchid dies off
Balance for the mutual benefit
Honey BeesColony Collapse Disorder (CCD)
Death of hives in a matter of days
2006 and 2007: 30% of U.S. hives
2008: lost 35% of 2.5 million hives
Severe consequences to human agriculture
Cause of CCD?
GM crops
use of monocultures
insecticides and herbicides
diseases/pests
unknown
multiple causes
Importance of insects:
Honey Bees
Pollinators of agriculture (30%)
- fruit trees, vegetables, berries
Bees for hire!
Very successful
High organized society (Eusocial):
Queen, Drone (reproductives)
Workers (sterile daughters, specific tasks),
General pollinators (variety of flowers)
Intelligent (memory, complex maps,
communication)
Leaf cutter ants39 species
Eusocial society: different castes
Soldiers, workers
Cut, move leaves back to nest
Chew and feed the leaves to fungi
Eat the fungi (species specific)
Leaf cutter and foreign fungiCarry around bacteria (antibiotics!)
Ant, fungi, bacteria relationship
Normal human fauna
>1,000 species
Bacteria (100,000 billion)
Fungi
Protozoans
Multicellular organisms
follicle mites
parasites
Humans as an ecosystem
Humans as an ecosystem
How did you get them?
Infants born without
Sources: air, mothers milk, food, environment
Benefits:
Digestion (e.g., plant material)
Clean-up of your waste (e.g., dead skin cells)
Cost:
Cause disease if not kept in checkWhere did they come from?
Invaders that stayed
Humans evolved defenses to control them
Microbes evolved to be less virulent
Provide
habitat for diversity of animals (100,000 species)
“Rain forests” of the ocean
tourism
medical products
food
shoreline protection
Coral reefs
http://batchisthenewshit.files.wordpress.com/2007/
06/coral_reef.jpg
Corals provide algae with nitrogen & CO2
Algae provide food for coral (photosynthesis)
Mutualism!
Algae may be 50% of the coral biomass
Coral and algae
Problems:
Coral bleaching
Loss of algae
Coral dies
Why?
Climate change
in warmer water corals expel algae
coral also are more prone to disease
Types of InteractionsType of relationship varies between species
Mutualism (+,+): mutually beneficial
Leaf cutter ant – fungus
Corals - algae
Parasitism (-, +): one hurt, one helped
broadly can define predator-prey
Cheetah (+), Gazelle (-)
Gazelle (+), Grass (-)
Commensalism (+, 0): one helped, one unaffected
Barnacles (+), Whale (0)
Relationships can vary with circumstances!
Summary:
Arthropods are the most successful phylum on Earth
Insects are the most dominant class of arthropods
Their diversity is explained by co-evolution with plants and their “tool kit” of appendages
Diversity of forms also stems from cooperation
among species
Humans are part of this system too!
Ends Organism section
next: Unique
Next time: Variation
Read: Ch. 10.1-10.4, 11.1-11.5
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