Biodiversity the variety of life on earth species

Biodiversity • the variety of life on earth • “species richness”

Why is biodiversity important? � each species, no matter how small has an important role to play in an ecosystem � ensures natural stability for all life forms � healthy ecosystems can better withstand recover from a variety of disasters

Natural Services A healthy biodiversity provides… ◦ ◦ ◦ ◦ ◦ Clean water Soil formation Nutrient recycling Pollution breakdown Climate stability (absorption of carbon dioxide) Variety of food sources Medicine, pharmaceutical drugs Wood, lumber, paper products Recreation and tourism

Human Impact on Biodiversity Humans have accelerated the extinction rates of many species through … � Habitat destruction � Invasive species � Pollution � Population growth (human) � Over-exploitation (hunting, consumption)

How important is soil? 90% of world’s food comes from agriculture … which means SOIL

Soils are degraded by… Erosion 2) Nutrient loss 3) Build up of salts 4) Compaction 5) Pollution 1)

Soil Biodiversity �Healthy soils have many species, including bacteria, fungi, protists and invertebrates

What to look for… • Annelida = earthworms • Isopoda = pill bugs • Acarina = mites • Gastropoda = snails • Diplopoda = millipedes • Chilopoda = centipedes • Coleoptera = beetles • Hymenoptera = wasps, bees, ants • Collembola = springtails • Araneae = spiders

Annelida � Segmented worms � 1700 species � Detritivores � Ragworms, earthworms and leeches

Isopoda �Crustaceans � 7 pair of legs �Gas exchange occurs across gills toward rear of body �Wood lice, pill bugs

Acarina � An order of arachnids (spiders) � Mites: very small, many live freely in the soil and some are parasites � Ticks: all are blood sucking parasites � Body segments are fused to appear as one body mass Adult deer tick Dust mite

Gastropoda Snails and slugs � detritivores �

Diplopoda � Millipedes � 2 pair of legs per segment, except first segment � do not have a 1000 legs (36 -400) � Slow moving � Detritivores

Chilopoda � Centipedes � One pair of legs per segment � Always an odd pair of legs � First pair of legs are venomous claws � Most are carnivores

Coleoptera � Beetles � Most diverse order of insects � 40% of describes insects are beetles � Elytra: hard cover on front wings

Hymenoptera � Wasps, bees, ants � name refers to heavy, membranous wings � hindwings are connected to forewings

Collembola � Springtails � Small, less than 3 mm � Very abundant in the soil � Abdominal appendage that looks like a tail

Araneae � Largest order of arachnids (spiders) � Air breathing � Venomous mouth parts � 4 pair of legs � 2 body segments

Soil Fertility � Soils 1. 2. 3. 4. 5. ability to a support life depends on … Available nutrients and nutrient holding capacity Infiltration of water and water holding capacity Spaces for air, aeration p. H near neutral (7) Low salt content

Soil Texture � Proportion of sand, silt and clay ◦ Sand - largest ◦ Silt - medium ◦ Clay – smallest � Affects workability – the ease at which a soil can be cultivated