Download Introduction to Ecology

Introduction to Ecology
Part II
What is a producer?
 Autotrophs like plants, protists, and bacteria that make their own food
What is a consumer?
 Heterotrophs that cannot make their own food.
Species Interaction:
 Predation:
o An individual of one species eats all or part of an individual of another
species.
o Predator – organism eating
o Prey – organism being eaten
 Predator Adaptations:
o Natural selection favors the evolution of predator adaptations for finding,
capturing, and consuming prey
 Acute heat sensors to webs to camouflage hair to specialized teeth
 Ex 1: Rattlesnakes have acute sense of smell and heat sensitive pits
below their nostrils.
 Ex 2: Sticky webs of spiders to flesh cutting teeth of wolves
o Natural selection also favor prey to be able to avoid, escape, or ward off
predators
o Animal prey adaptations:
 Hide, camouflage, chemical defense, fake eyes and heads, bright
colors, to mimic other dangerous animals
o Plant prey adaptations:
 Defense includes: sharp thorns, spines, sticky hairs, tough leaves,
to being poisonous, irritating, or bad tasting.
Competition:
 Interspecific competition:
o Is a type of interaction in which two or more species use the same
limited resources
o Two populations competing for the same resources may end up
reducing/eliminating one of the competitors
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 Competitive exclusion:
o Is where one species uses the limited resources more efficiently than the
other species does
o Ex: Barnacles off the coast off the Scottish coast between Chthamalus
stellatus and Semibalanus balanoides.
 The C. stellatus could live high and low on “shore rock” but due to
competition S. Balanoides out competed it restricting the C. stellas to
the upper portion of the shore rock
Symbiosis:
 Symbiosis is a close, long-term relationship between two organisms
 There are three types of symbiotic relationships:
o Parasitism
o Mutualism
o Commensalisms
 Parasitism:
o In parasitism, the prey is called the host.
o Predator is called the parasite
o One organism is harmed (host) while the other organisms benefits
(parasite)
o Usually does not result is host death
 Examples; Aphids, lice, leeches, fleas, ticks, and mosquitoes
o Ectoparasites:
 Live inside their hosts body
 Ex: Protists; tape, heart, round worms, and lamprey
o Parasites have a negative impact on their host’s health.
o Host defense:
 Skin, tears, saliva, mucus membranes and the immune system
 Mutualism:
o Relationship where both (two) species have some benefit from each
other
o Pollination is the most important mutulistic relationship on Earth
o Termites are able to digest cellulose due to a mutulistic protozoa called
Trichonympha
 Commensalism:
o Is an interaction in which one species benefits and the other is not affected
o Species that scavenge for leftover food items are often commensal species
 Best know examples are small tropical fishes in relation to sea
anemones
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Species Richness:
 Is the number of species or simple count of species in the community
 Each species contributes one count to the total regardless of whether the species’
population is one or 1 million
 Varies with latitude - the closer a community is to the equator the greater the
number of species
o Species is the greatest in the tropical rain forest
 Larger areas usually contain more species than smaller ones
 Species interaction also promotes species richness. (competition can keep
species from overcrowding others)
Succession:
 Ecological succession is a gradual sequential growth of a community of species in
an area
 Primary succession:
o Development of a community in an area that has not supported life in
the past
o Bare rock, sand dunes, or volcanic island
o No soil present (can take 200+ years to reach vegetation)
 Secondary succession:
o Sequential replacement of species that follows disruption of an existing
community.
o Regrowth of organisms after a severe natural disaster (fire, tornado,) or
farming, logging, or mining
o Soil already present (takes about 100 years)
 Pioneer community:
o A community that is actively undergoing succession.
o Not stable, still changing with time
 Climax community:
o A community that reaches a stable end point (redwood forest)
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Review Questions
1. Describe one adaptation of a herbivore and one adaptation of a carnivore for obtaining
food.
2. Identify two possible results of interspecific competition
3. Identify the ways that parasites are similar to predators
4. Explain how two similar species of birds could nest in the same tree and yet occupy
different niches.
5. How does predation on plants differ from predation on animals, in terms of the usual
effect on the prey?
6. Explain how species richness can affect community stability
7. Explain the relationship between species richness and latitude
8. Identify between primary and secondary succession
9. Why is the species-area effect important in efforts to conserve species?
10.Do you agree with the following statement: “Communities are usually in a state of
recovery from disturbance”? Consider both animals and plants in your answer