Introduction to Biodiversity . What the syllabus says…. Explain the concept and importance of biodiversity in tropical rainforests. 1. What is Biodiversity? . Definitions….. . Biodiversity is the variation of life forms within a given ecosystem, biome, or for the entire Earth. .
Explain the concept and importance of biodiversity in tropical rainforests
Biodiversity is the variation of life forms within a given ecosystem, biome, or for the entire Earth.
Biodiversity is the totality of genes, species and ecosystems in a given area
Biodiversity is the variability among living organisms from all sources..... Terrestrial, marine and aquatic ecosystems and the ecological complexes of which they are a part: this includes diversity within species, between species and of ecosystems.
A clear, concise definition …… p.38 IB Study Guide
Genetic diversity- The genetic variation within species. This can be in populations that have been separated geographically, but also amongst individuals within single populations.
Ecosystem diversity- this looks at the variety of different ecosystems or habitats that occur within an area and takes into account the biotic and abiotic components.
Range of species
Abundance of species
Total number of species
Large-scale global ecosystems (biomes) differ in their biodiversity. The following are examples of biomes (global ecosystems) ordered from higher to lower latitudes. There are clear differences in climate (temperature and precipitation) and therefore biodiversity.
A key concept is NET PRIMARY PRODUCTIVITY. This is the amount of new biomass that is produced each year (biomass =Total amount of living matter present at any given moment in an ecosystem. Expressed as dry weight of tissue per unit area)
NPP is given in grammes per m2 per year.
Located mostly in the centre of continents within 40 -600 N & S of the equator
Temperatures Winters are cold (-200C) summers are hot (+200C)
Precipitationis in the form of snow in winter and heavy showers in summer. Annual totals in the order of 400mm/year
Vegetationis almost entirely grassland. The wetter the area the taller the prairie grasses. Human use of these areas is dominated by wheat and cattle farming.
NPP: 600 gms/m2/year
Located 40 -600 N & S of the equator, nearer the coasts
TemperaturesSummers are relatively cool, winters are mild
Precipitationis mostly rain which falls in the winter months. It totals around 1000mm/year
Vegetationis deciduous woodland (oak, ash, elm and beech) which lies dormant in the winter when light levels are low
NPP: 1200 gms/m2/year
Located within 100 N or S of the equator
Temperaturesare high all year
Rainfallis over 2000mm and falls throughout the year
Vegetationis dense and mostly trees often found in 3 layers – shrub layer, canopy and ‘emergents’ (forest giants)
NPP: 2200 gms/m2/year
Climate (precipiation and temperature)
Precipitation (total, variations over time, intensity)
Temperature range (range from min to max)
Length of growing season
Amount of sunlight for photosynthesis
Planet Geography p.311 for summary of climate types and biomes
Advanced Geography p.212 for brief notes on characteristics of TRF climate.
Nutrient cycling occurs within an ecosystem.
Nutrients are the chemical elements and compounds organisms need to grow and function.
Nutrient cycling in the TRF
Use the following text to make brief notes…
Advanced Geograpy p.206
You need to understand how nutrient cycling works and the characteristics of nutrient cycling in the TRF
If you are new to ecosystems and haven’t much of an idea about nutrient flows, trophic levels and food chains, a read through the following texts will give you a brief introduction. Whilst these concepts are not specified in the syllabus, it is important to understand the processes so that you can then see how reduction of biodiversity in the TRF has important environmental consequences.
Planet Geography p.303-307
Advanced Geography p.204-206
4 - Tertiary Consumers
3 - Secondary Consumers
2 - Primary Consumers
1 - Primary Producers
An ecosystem is a complex set of relationships among the living resources, habitats and residents of an area, including plants, birds, trees, fish and microorganisms, soils, water and people.
‘The Guardian’ environment section has a part dedicated to the issue of biodiversity (link on our website). There is a wealth of information on this topic and it is well worth a visit.