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

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