Transcript Evolution to Ecology

Evolution to Ecology
Chapters 19 - 20
Problems of the 21st Century
• Increasing population – 6.9 billion
– Struggle for resources – food, water, space, air
• 6th mass extinction event
– 5th was 65 MYA – dino extinction
– 20% of all species lost in past 2000 years
Ozone layer degraded by CFC’s
– Damaging UV rays
• Greenhouse effect & Global Warming
– CO2, methane, water vapor (all results of
cellular respiration)
We are all connected
Ecology
• Study of interactions &
interdependence of life
What is life?
Life evolved from
a common
ancestor
Continental
drift gave
us different
habitats
Regional differences (habitat)
reflect adaptations for survival
Adaptations for survival gave us
different niches
Niche - Role an
organism plays
in the
environment
generalist
specialist
Ecosystem (habitat location)
Ecosystem is made of…
• Biotic factors
Resources
• Abiotic factors
Resource “tolerance” to changes in
ecosystem
• Tolerant (“fight”) – Acclimation
– Become “used to” a range of conditions within
tolerance levels
• Conformer – changes internal conditions to suit the
environment
– Ex: ectothermic lizards
• Regulator – uses NRG to keep internal conditions stable
(homeostasis)
– Ex: bees and their jobs
• Intolerant (“flight”) – Migration or Dormancy
Population
• Grouping of species
living in the same
place, at the same
time, able to
interbreed
successfully.
“r” strategists vs. “k” strategists
Populations are described by…
• Size
• Density
• dispersion
Dispersion types
Survival of a population
• Based on Darwin’s theory of evolution
and available resources
–O
–S
–V
– NS
Recipe for survival
• Requires resources (biotic, abiotic)
Population Graphs
Darwin’s Model of overproduction
Carrying Capacity
Limiting Factor