Biomagnification, Biomes, Population (Climate and Ecosystem Dynamics)

Biomagnification, Biomes, Population (A, B)

Biomagnification

• when toxins enter food chains and pass from one trophic level to another

• these pollutants become concentrated in tissues as they move up the food chain

Bioaccumulation- First step

• increase in concentration of a pollutant from the environment to the first organism in a food chain (producer)

• taken in and stored “by mistake”

• toxins often resemble essential nutrients

Biomagnification- Second step

• increase in concentration of a pollutant from one link in a food chain to another

• begins when a producer is eaten

• if that biomass contains a pollutant, it will be taken up in large quantities by the consumer

• substances get concentrated in tissues as it moves up the food chain

Conditions Needed to Biomagnify

The pollutant must be...

1. Long-lived

2. Concentrated by producers

3. Fat-soluble

4. Biologically active (has some negative effect)

What are biomes?

• large geographic area that has a specific climate (average temperature and rainfall)

• with each biome exists organisms (plants, animals, etc.) with characteristic adaptations best suited to survive there

How are biomes formed?

• they are distributed across the Earth based primarily on climate

• in some areas far apart, you will sometimes find similar plants and animals because the climate is similar

Factors affecting climate

• Latitude:

  • the farther you move north or south of the equator, the colder the temperature gets

• Elevation:

  • the higher you go in elevation, the colder the temperature gets

Why are biomes important?

• they are areas of specific animal and plant life

• animals and plants have adapted to the climate and conditions specific to each biome

• by studying adaptations, scientists can track natural selection

Population

all the individuals of the same species living in the same place at the same time

Affect of a link in a food chain

When anything affects one link in a food chain, the whole chain is affected

A farmer puts poison to kill rats but a huge number of mice die. What are the consequences?
(ex. Consider - grass → mice → fox)

= grass will flourish, fox will decline in numbers

Natality

• birthrate, ratio of total live births to total population in a particular area over a specific period of time

Mortality

• death rate, ratio of the total number of deaths of total population

Immigration

• number of organisms moving into an area occupied by population

Emigration

• number of organisms moving out of the area occupied by population

Carrying capacity

The maximum number (of a population) that an ecosystem can support with its resources

Example of carrying capacity

vegetable garden - plant too many vegetables =
not enough space, soil, light and water for proper growth

Limits to carrying capacities

a) amount of materials and energy available to organisms

b) number of organisms in trophic levels above and below

c) competition between organisms

i. Intraspecific competition

- competition among members of the same species

ii. Interspecific competition

- competition between different species

How do scientists study population trends?

• by collecting, ​graphing, and analyzing data

Population density

• the measure of population per unit area

• different species have different expected densities