Population Growth

Population Growth Rate

• Population Growth Rate: How fast a population changes in size over time.

Dispersal

• Dispersal: The movement of offspring away from their parents, which affects population size and growth.

Migration

• Migration: Seasonal movement of individuals or populations, also impacting population size.

  • Immigration = the movement of an organism into a new area

    • Leads to an increase in population size

  • Emigration = the movement of an organism out of a population or area

    • Leads to a decrease in population size

Exponential Growth

1. Exponential Growth:

   • Happens when resources are unlimited.

   • Population size increases quickly over time.

   • Shown as a J-shaped curve on a graph.

   • Example: Bacteria growing rapidly in a petri dish with unlimited nutrients.

   

Logistic Growth

1. Logistic Growth:

   • Happens when resources are limited.

   • Growth slows as it reaches the carrying capacity (maximum number an environment can support).

   • Shown as an S-shaped curve on a graph.

   • Example: Deer population in a forest with limited food and space.

     

Biodiversity

• Biodiversity: The variety of life in an area, including different species, genetic differences, and the ecosystems they form.

Richness

• Richness: Number of different species in an ecosystem.

  • Example: A forest with 20 different tree species has a richness of 20.

Evenness

• Evenness: How evenly the individuals are spread among species.

  • Example: Garden A has 10 flower species with equal numbers; Garden B has 10 flower species, but one dominates. Garden A has higher evenness.

Biomass

• Biomass: Organic material from plants and animals used as a renewable energy source.

  • Examples: Wood, agricultural crops, animal waste.

Uses of Biomass

• Uses:

  • Direct Combustion: Burning biomass to produce heat.

  • Biofuels: Converting biomass into liquid fuels like ethanol.

  • Biogas: Decomposing organic material without oxygen to produce methane for heating or electricity.

Pros and Cons of Biomass Use

• Benefits: Renewable, reduces waste, and is carbon neutral.

  • Challenges: Requires land and may not be very efficient.