evolution to ecology chapters 19 - 20. problems of the 21 st century increasing population – 6.9...
TRANSCRIPT
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