Biodiversity , Species , Interact and Population control

1. Predation-Prey(+,-)

   Nota:

   • • Member of one species (the predator) feed directly on all or part of a living organism of another  species (the prey). Predator benefit, prey harmed. • Predator strategies – Herbivores can move to plants – Carnivores • Pursuit, Ambush – Camouflage – Chemical warfare • Prey strategies – Evasion – Alertness = highly developed senses – Protection = shells, bark, spines, thorns – Camouflage – Mimicry – Chemical warfare – Deceptive look or behavior
   1. co-evolution

      Nota:

      • – Intense natural selection pressure on  each other – Each can evolve to counter the advantageous traits the other has  developed –Bats and moths
2. Interspecific Competation(-,-)

   Nota:

   • • competition b/w members of two or more  different species for food, space and any  other limited resources. • Humans – compete with other species • No two species can share vital limited  resources for long • Resolved by: – Migration – Shift in feeding habits or behavior – Population drop – Extinction • Intense competition leads to resource  partitioning
3. Mutualism(+,+)

   Nota:

   • • Both species benefit • Nutrition and protection • Gut inhabitant mutualism • Pollination: having pollen and seeds  dispersed for reproduction, • Nutritional mutualism: being supply with  food (i.e., lichens, rhizobium bacteria,  bacteria in a digestive system) • protection
4. Commensalism(+,0)

   Nota:

   • Benefits one species with little impact on other :
5. Parasititism(+,-)

   Nota:

   • Occurs when one species (the parasite)  feeds on part of another organism (the  host) by living on (Ecto parasite) or in the  host (Endo parasite) • Parasite benefits, host harmed • Parasites promote biodiversity • usually smaller than its host, • remains closely associated with, draw  nourishment from and weaken the host  over time, • rarely kill the host.

Nota:

• Carrying capacity Biotic potential Exponential growth Logistic growth

1. Carrying cap (k)

   Nota:

   • The number of  individuals of a given species that can be sustained indefinitely in a given space =  carrying capacity (k) • biotic potential and environmental resistance decide growth
2. Exponential

   Nota:

   • few resource  limitation, population can grow at its intrinsic rate of increase
   1. J curve (r-selected species)

      Nota:

      • – High rate of population increase – Reproduce & spread rapidly when conditions  are favorable – Opportunists
      1. r - intrinsic rate of increase

         Nota:

         • –Rate under unlimited resources – no population can grow indefinitely –Nature limits population growth due to  resource limitation and competition  among species for those resources – Environmental resistance
3. Biotic potential
   1. ideally
4. Logistic (near k)

   Nota:

   • growth rate decrease as population grow larger. With time, size  stabilizes at or near the carrying capacity  (k) – sigmoid curve (S-shape)
   1. Sigmoid (k-selected species)

      Nota:

      • – Competitors – Typically follow a logistic growth curve – Slowly reproducing

Nota:

• Structure and species composition of  communities and ecosystems change in  response to changing environmental conditions through a process called  ecological succession

1. (Intermediate) disturbance

   Nota:

   • Moderate disturbance have greatest species  diversity
2. Primary - lifeless

   Nota:

   • gradual establishment  of biotic communities on nearly lifeless ground
3. Secondary - some biotic community appear

   Nota:

   • the reestablishment  of biotic communities in an area where some types  of biotic community is already present
4. Disturbance - new condition

1. Dynamic
2. Stage - PTIP
   1. Preindustrial
   2. Transitional
   3. Industrial
   4. Postindustrial
3. Distribution - CUR
   1. Clumping-most occur

      Nota:

      • • Resources not uniformly distributed • Protection of the group • Pack living gives some predators  greater success • Temporary mating or young-rearing  groups
   2. Uniform
   3. Random
4. pop = (B+J)-(D+E)

   Nota:

   • population = (births + immigration) -  (deaths + emigration)
5. AGE( pre,post) reproductive

   Nota:

   • Age structure –Pre-reproductive stage (0-14 years) –Reproductive stage (15-44 years) –Post-reproductive stage (45 years)

Nota:

• • Population not transition smoothly  from exponential to logistic growth • Overshoot carrying capacity of  environment due to fast resource  consumption • Caused by reproductive time lag • Dieback, unless excess individuals  switch to new resource

Nota:

• Evasion- run away Mimicry - copy like other Pursuit-  attack Ambush - hiding Biotic potential- max rate at which the population of a given species can increase when there are no limit in its rate of growth Environmental resistant- all of the limiting factors of the growth of a population Intrinsic Rate of increase - rate of which a population could grow if it had unlimited resources 

Nota:

• • Interactions b/w species affect their use  of resources and their population sizes • There are always limits to population  growth in nature • Changes in environmental conditions  alter the composition of species and their population sizes in communities  and ecosystems (ecological succession)