Transcript Ecology ppt.

Ecology
Levels of Organization
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Biosphere
Biome
Ecosystem
Community
Population
Individual
FoodChain
• Producer
• Consumer
• Path of food therefore energy from a given
top order consumer back to a producer.
Food Web
All the feeding relationships in an ecosystem
Pyramids
• Biomass decreases going
up in the food chain
because:
• 1. Not everything in the
lower levels gets eaten
• 2. Not everything that is
eaten is digested.
• 3. Energy is always being
lost as heat.
10% rule
• Only 10% of the energy available in one
trophic level is transferred to organisms at
the next trophic level
• Would it make more ecological sense then
to be a vegetarian?
Absolutely!!
• Eating from the top of the
pyramid all the time we
are essentially consuming
more land to get our
energy needs met.
• Environmentalists say
eating vegetarian reduces
your footprint more than
any other lifestyle change.
Laws of Thermodynamics
• Energy is neither created or destroyed but
may change forms.
• Energy is moving toward disorder, entropy,
or unusable energy such as heat.
www.bom.gov.au/lam/climate/levelthree/ climch/clichgr1.htm
Biodiversity
Extinction
• Extinction of a species occurs when it ceases to
exist; may follow environmental change - if the
species does not evolve
• Evolution and extinction are affected by:
– large scale movements of continents
– gradual climate changes due to continental drift or
orbit changes
– rapid climate changes due to catastrophic events
Extinction
• Background extinction - species disappear at a low rate as
local conditions change
• Mass extinction - catastrophic, wide-spread events -->
abrupt increase in extinction rate
• Five mass extinctions in past 500 million years
• Adaptive radiation - new species evolve during recovery
period following mass extinction
Community
Relationships
Niche
a species’ functional role in its ecosystem; includes
anything affecting species survival and reproduction
1.
2.
3.
4.
Types of resources used
Interactions with living and nonliving components of ecosystems
Range of tolerance for various physical and chemical conditions
Role played in flow of energy and matter cycling
Niche is
the species’ occupation and its
Habitat
location of species
(its address)
Species Interaction
Competition
any interaction between two or more species
for a resource that causes a decrease in the
population growth or distribution of one of the
species
Could be a Limiting Factor:
Density Dependent
Density Independent
Competition
Competition
Predation: prey adaptations
• Avoid detection
– camouflage, mimics,
– diurnal/nocturnal
• Avoid capture
– flee
– resist
– escape
• Disrupt handling (prevent being eaten)
– struggle?
– protection, toxins
Herbivory
Rewards of Mutualism
• Food: energy and nutrients
• Protection:
– from other species (competition, predation)
– from the physical environment (shelter)
• Gamete or zygote dispersal (the most common of
all)
• Pollination and fruit dispersal (between plants and
animals).
Pollination (hummingbird/bee
and flowering plants)
• animals visit flowers to collect nectar
and incidentally carry pollen from one
flower to another
• animals get food and the plant get a
pollination service
•
Yucca
moth
and
yucca
Yucca’s only pollinator is the
yucca moth. Hence entirely
dependent on it for dispersal.
• Yucca moth caterpillar’s only
food is yucca seeds.
• Yucca moth lives in yucca and
receives shelter from plant.
Lichen (Fungi-algae)
• Symbiotic relationship of algae and
fungae…results in very different growth formas
with and without symbiont.
• What are the benefits to the fungus?
Seed Disperser
• Many birds and mammals consume fruits and
incidentally disperse the seeds contained in those
fruits
– Animals get food and the plant gets seed dispersal
(often with fertilizer)
Symbiosis in animal cells or tissues
(aphids and bacteria)
• Aphids need bacteria to metabolize
photosynthate.
• Buchnera is a modified bacterium
that retained its genome for amino
acid production while losing much
of its total genome.
• 10-50 million Buchnera cells per mg aphid
fresh weight.
Ant-tended plants
• Ants live inside swollen
Acacia thorns or hollow
stems, e.g. Cecropia trees.
• Patrol for caterpillars or
leaf predators and storm
out to repel
intruders…including you!
Commensalists
• Benefit from the host at
almost no cost to the
host
• Eyelash mite and
humans
• Us and starlings or
house sparrows
• Sharks and remora
Parasites
Parasites: draw resources from host without killing the host
(at least in the short term).