C2.1 - The Diversity of Life

Organizing Life: Criteria

• Morphology
• Habitat/niche
• Locomotion
• Colour
• Evolutionary history
• Food source

Statistics

• 1.5 mil. species of animals named
• 1000s more animals being named each yr.
• All species named so far believed to be <20% of all living animals
  • <1% of animals, incl. those that lived in the past
• ~7.5 mil. animal species on Earth
• Best guess; do not include bacteria, protists, fungi and plants

Examples of Species Richness

Region	Area (sq. km)	Bird Species	Tree Species
Panama	15	443	1,320
Costa Rica	15	410	1,668
Ecuador	15	480
Peru	50	554	1,370

• 1980s: Entolomologist Terry Erwin sampled 19 tropical trees
• Collected 955 species of beetle
• Extrapolated that there was ~30 mil. animal species in world
• entolomologist: person who studies insects
• mammologist: person who studies mammals

Biodiversity

• biosphere: zone on Earth where all life exists
• gene: units of inherited information that determine specific characteristics or functions
• biodiversity: variety of life in the world
  • product of mil. of yrs. of evolution
• symbiotic relationship: two organisms work together and help each other

Honeybees

• Honeybees
  • North America used to have 4,000 diff. native pollinators
  • settlers brought honeybees around 1800s
  • honeybees outcompeted native pollinators
  • if honeybees die, who is going to pollinate the plants?
• Mysterious Disappearance of Honeybees
  • pesticides?
  • Varroa mite (sucks on bee’s blood until bees become weak and die)
    • contains viruses like Israeli acute paralysis virus (IAPV)
    • IAPV immobilizes bees and ultimately kills them

Levels of Biodiversity

• genetic diversity: sum of all different forms of genes present in a particular species
  • allows for population resistance against disease / predators
  • farmers often grow genetically similar crops of wheat to max. food production
    • same equip., fertilizers, techniques
    • vulnerable to diseases and pathogens
• species diversity: variety of species and relative abundance of species in given area
  • allows ecosys. to survive environ. changes
• ecosystem diversity: diverse range of habitats, various organisms that live in habitats, and relationships that connect them

Different Views of Environment and Ecosystems

• instrumental value: ecosystem’s sources of economic wealth
  • i.e. food, timber, fuel, medicine
• Sources of inderect economic wealth
  • i.e. pollination, genetic info., recreation
• Cultural value for Aboriginal groups
• intrinstic value: value that cannot be measured in monetary terms
• Ecosystems and their components have a value that cannot be measured in dollars and cents
• Plants and animals have a value purely in themselves

“A thing is right when it tends to protect the health and integrity of ecosystems…. It is wrong when it tends otherwise.” — Aldo Leopold, 1949

Value of Biodiversity

• Insects, bats, birds, and other animals pollinate flowering plants and crops.
• Micro-organisms make nutrients available and break down toxic substances in water and soil.
• Ecosystems cycle carbon, nitrogen, and oxygen.
• Ecosystems clean air, purify water, control erosion, prevent floods, and modify climate.

keystone species: species that have disproportionately large effect on ecosystems in which they live

Taxonomy

• taxonomy: science of naming and classifying organisms
• Cf. systematics: science of determining evolutionary relationships among organisms
• Nested hierarchial system w/ defined levels of organization
• taxon: defined level in organization of life
  • pl. taxa
• 8 recognized taxa
  • In order from broadest to most specific:
  • Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
• 3 Domains: Bacteria, Archaea, Eukarya
• 6 Kingdoms: Eubacteria, Archaebacteria, Protista (protists), Plantae (plants), Fungi, Animalia (animals)

Classification Example

	Leopard	Modern Humans
Domain	Eukarya (eukaryotes)	Eukarya (eukaryotes)
Kingdom	Animalia (animals)	Animalia (animals)
Phylum	Chordata (chordates)	Chordata (chordates)
Class	Mammalia (mammals)	Mammalia (mammals)
Order	Carnivora (carnivores)	Primates (primates)
Family	Felidae (felines)	Hominidae (hominids)
Genus	Panthera (panthers)	Homo (mankind)
Species	P. pardus (leopard)	H. sapiens (wise)

Binomial Nomenclature

• binomial nomenclature: Latin 2-part unique naming sys. used to classify species
• binomial: two-part Latin name
• also known as a species’ scientific name
• Developed by Carolus Linneaus in the 1750s
• Order of naming: Genus species
• Species: members of a populaton that can interbreed and produce viable offspring
• i.e. Canis familiaris (the family dog)
• Linnaeus grouped species according to their morphology
• morphology: study of form and structure of organisms

Importance

• malaria (deadly disease) spread through mosquito bites
• insecticide to mass kill mosquitos failed to control disease
• classification and targeting of specific mosquitos controlled disease
• Anopheles maculipennis (mosquito) carries malaria

Phylogeny (from Evolution in Textbook)

• phylogeny: evolutionary history of a species or group of organisms
• Organisms can be arranged by evolutionary relationship on a phylogenetic tree or a cladogram
• phylogenetic tree: diagram that reflects the hypotheses of evolutionary relationships
  • node: point where tree splits; repr. common ancestor

Cladistics

• cladistics: determine sequence of branches in phylogenic tree via clades
• derived characters: homologous structures in a clade
• cladogram: diagram that specified derived characters of clades
• A clade on a cladogram represents one branch on a phylogenic tree
• clade: group of a common ancestor and all descendants
• All organisms in a clade must have homologous structures that do not occur outside the clade

Phylogeny and HIV Evolution

• Case in Libya (1998)
  • Police arrest group of doctors and nurses
  • charge w/ bioterrorism bcz. they believe ppl. intentionally infected children w/ HIV
• Scenario 1: Medics Could’ve Infected Children
  • new strains would’ve developed from single strain after 1998
• Scenario 2: Infections Began Before Medics Arrive
  • lineages of HIV split before medics arrive
  • ✅ 2nd scenario correct
  • causes: dirty needles and poor hygiene practices
• Libyan court convicted 6 medics to death
  • eventually transferred back to Bulgaria
  • recieved presidential pardons and set free

Phylogenetic Tree

Cladogram

Dichotomous Keys

• dichotomous key: tool used to identify unfamiliar organisms
  • dichotomous greek for “to cut in two”
• Used to identify organisms down to the species level
• Like a roadmap to a specific destination
• More accurate than a field guide

Human Impact on Biodiversity

• dead zones: areas w/ low levels of oxygen in water that cannot support life
  • dredging (removal) and development for farming, roads, and housing reduces biodiversity
  • fertilizer runoff creates dead zones in water
  • ecosystems like Great Lakes can recover with proper care
  • agreements like the Great Lakes Water Quality Agreement have helped reduce damage
• extinct: when there are no alive individuals of a species left
  • mass extinction period taking place (evidence below)
  • 12% of 9,900 known bird species endangered
  • 300 / 20,000 plant species in risk (N.A.)
  • 37% of known fish have become extinct / at risk

Threats to Biodiversity

• habitat loss: loss of habitat (place to live)
  • habitat fragmentation: alteration of small areas within large region; creating patchwork of altered and original habitats
    • i.e. roads split habitat into two
  • Forest Stewardship Council work to conserve and protect forest habitats
• invasive species: non-native species that harm ecosystems where they are introduced
  • i.e. kudzu (Jap. plant) in N.A. (brought to control erosion)
  • emerald ash borer (arrived in wood packing material)
  • Asian carp
  • zebra mussels (emptying of ship ballasts)
• pollution: introducing contaminants that harm ecosystems
  • i.e. coal power, pesticides
• overexploitation: using resources faster than they can reproduce
  • i.e. cod fishing (479,141 tons → 12,490 tons catched from 1988 - 95)
• climate change: long-term changes of weather patterns
  • Potential Effects
    • disease outbreaks (i.e. from insects)
    • plant migration
    • animal migration
    • extreme weather
    • increased CO₂ levels (changes pH of water)
    • water availability and qty.
• synergistic effects: combination of several harmful human activities

Conserving Biodiversity

• conservation biology: application of biology to counter loss in biodiversity
  • The Convention on Biological Diversity signed by 161 countries incl. Canada
  • ex-situ conservation: protecting species by removing them from their natural habitats
    • i.e. storage of seeds
    • zoos
    • botanical gardens and reserves
    • last resort
  • in-situ conservation: protecting species in their natural habitats
    • i.e. establishing protected areas
    • restoring habitats
• ecological footprint: estimate of all the land and water needed to produce the resources you consume and to absorb the wastes you produce
  • avg. Canadian uses 8.9 ha
  • 17 football fields
  • would need 5.7 Earths if everyone lived like that