Biodiversity Flashcards
What is biodiversity?
variety of life
a continuum
What can biodiversity be subdivided into?
- Genetic diversity - underlies behavioural and morphological diversity
- Species diversity - variety of species that comprise a biological community
- Community and ecosystem diversity - different biological communities and their associated ecosystems
What is genetic diversity?
total number of genetic characteristics in the genetic makeup of a species
What is the processes of DNA mutation to Phenotype?
DNA mutations -> Alleles -> Proteins -> Phenotype (including behaviour)
What are the definitions of species diversity? (3)
- Biological species concept
- Morphological species concept
- Evolutionary species concept
What is biological species concept as a definition of species diversity?
different species do not breed with each other
What is morphological species concept as a definition of species diversity?
a group of individuals that is morphologically, physiologically, or biochemically distinct
What is evolutionary species concept as a definition of species diversity?
a group of individuals that share unique similarities of their DNA
What are examples of the difficulties with each definition of species diversity?
E.g. The western meadowlark (Sturnella neglecta) and the eastern meadowlark (Sturnella magna) = distinct species because they have different songs and do not interbreed - look very similar
E.g. natural hybridisation sometimes occurs e.g. tiger salamanders
How many eukaryotic species have been described so far?
1.24 million
How many eukaryotic species, on land?
1.05 million
How many eukaryotic species, in oceans?
0.19 million
How many eukaryotic species that are invertebrates (and beetles)?
0.75 million (including 0.35 million beetles)
What biases exist with the amount of species?
- towards large, abundant, widespread, temperate, terrestrial species
- many ‘new to science’ species have been long-known by locals
- small, cryptic species are underrepresented, especially prokaryotes
How is species diversity measured?
- comprised of species richness and species evenness
- populations can have the same number of species but different evenness
- Simpson’s diversity index - higher number = lower diversity, in contrast to the other measures
What do conservationists try to preserve?
- Trophic structure
- Food web complexity
- Species composition
- Trophic structure
what does a trophic pyramid describe?
- amount of energy and biomass at each level
- energy decreases at higher tropic levels - heat loss during respiration, and biomass decreases at higher tropic levels
- Trophic structure
What is a primary producer?
- obtain energy from sun (photosynthesis)
- terrestrial environments = flowering plants, gymnosperms, ferns
- aquatic environments = seaweeds, single-celled algae, cyanobacteria (blue-green algae)
- use solar energy to build organic molecules they need to live and grow
- Trophic structure
What are primary consumers?
- herbivores - eat photosynthetic species
- terrestrial environments = gazelles and grasshoppers eat grass
- aquatic environments = crustaceans and some fish eat algae
- intensity of grazing by herbivores often determines relative abundance of plant species and even mass of plant material present
- Trophic structure
What are higher consumers - secondary and tertiary consumers?
- secondary carnivores (e.g. foxes) eat herbivores (e.g. rabbit)
- tertiary consumers (e.g. bass) eat other carnivores (e.g. frogs)
- carnivores = usually predators, some specie combine direct predation w/ scavenging behaviour, and other species, known as omnivores, include a portion of plant foods in their diets
- Trophic structure
What are detrivores?
- decomposers - feed on dead plant and animal tissues and wastes (detritus), breaking down complex tissues and organic molecules
- in process - decomposers release biologically essential minerals (e.g. nitrates and phosphates) back into soil and water, where they can be taken up again by plants and algae
- decomposers = fungi and bacteria
- other animals that break down organic materials = vultures and other scavengers; dung beetles feed on and bury animal dung; worms break down fallen leaves and other organic matter
- if not present - organic material would accumulate and plant growth would slowly stop
- Trophic structure
What are parasites?
- live on or within host organism for all/part of their lives - may cause harm to host or weaken - PATHOGENS do cause harm
- pathogens and parasites - variety of protists, bacteria, fungi, viruses and animals (e.g. flatworms and flukes), infect plants and animals at all tropic levels
- effect of disease-causing organisms = especially important when host species is at high density and under stress - may occur at zoo or in habitat that has been fragmented or degraded by human activities
- spread of disease from captive or domestic species, such as domestic dogs, to wild species, (e.g. lions), can be a threat to rare species
How does trophic cascades occur?
- loss of single species can result in extinctions of multiple people
- a linked concept is functional diversity - the variety of ecological functions that species perform in ecosystems
- Food web complexity
What is linkage density (D)?
Average number of interactions between species
- Food web complexity
What is connectance (C)?
the proportion of all possible links between species that are realised
- Food web complexity
How to conserve species, relating to the food web?
conserve species they rely on
- Food web complexity
What makes species more or less vulnerable, relating to the food web?
fewer links = more vulnerable (less resilient)
- Species composition
- some species can be particularly important to their community/ecosystem
- e.g. ecosystem engineers: form habitats e.g. beavers, kelp, coral, net-spinning caddis fly larvae
- e.g. Keystone species: have high impact on other species through their interactions with other species (not via high abundance/biomass or through habitat creation)
- argument that conservation efforts should focus on species with high impact on the community
What are biogeographic realms?
large regions across globe where organisms share common geologic and evolutionary histories
How many biogeographic realms are identified?
8
What are biogeographic realms composed of?
biomes
What is a biome?
area that can be identified by their dominant vegetation type (on land) or dominant physical processes (in aquatic habitats)
What can biomes be further divided into?
Ecoregions
What is an ecoregion?
units of land containing distinct assemblage of natural communities and species
E.g. WWF divided terrestrial biomes into 867 ecoregions - used to recognise areas for conservation
Biomes
Tropical Forests
7% land area, contain > 50% world’s species
Biome
Coral Reefs
<0.1% of ocean surface area, but >25% of all marine species
Biome
Large tropical lakes and river systems
<0.01% of world’s water and ~ 0.8% of Earth’s surface
Support ~125,000 species
Biome
Mediterranean Communities
moist winters, hot dry summers = high plant diversity
occur in Mediterranean basin, Southwestern Australia, California, Central Chile, and the South African cape (which has 9000 endemic plants species)
How many biodiversity hotspots have been identified, how much biodiversity do they contain, and how much of the Earth’s land surface do they comprise?
25 hotspots of terrestrial biodiversity contain:
- 44% of all species of vascular plants
- 35% of all vertebrate species
Comprise 1.4% of Earth’s land surface
What region is biodiversity highest?
Tropical regions
Exhibited in marine, terrestrial and freshwater habitats
All major taxonomic groups
Been persistent over time
Why do tropical regions have higher biodiversity?
- biodiversity evolves through mutation, migration, natural selection and genetic drift - resulting in patterns of speciation and extinction
- processes don’t occur evenly
Tropics have: - greater area: species diversity increases predictably with area
- greater productivity: more sun and rain lead to greater plant productivity & more herbivores and carnivores
- more time: equatorial regions have had a stabler climate (e.g. no glaciation)
How have humans impacted biodiversity?
huge impact
wild mammals biomass declined 85% since rise of human civilizations
mainly driven by overhunting and habitat loss
What are the values of biodiversity?
- Intrinsic
- Instrumental
- Relational
What is intrinsic as a value of biodiversity?
-> Moral - Value based on individual sense of right and wrong
-> Ethical - Value based on social norms and codes of conduct
-> Religious - Value from a belief in a higher power
What is instrumental as a value of biodiversity?
-> Direct use - value of market goods and products that nature provides
-> Indirect use - value of the services nature provides to people
-> Option value - value of natural assets when used in the future
-> Non-use - value of leaving nature intact for future generations
What is relational as a value of biodiversity?
-> Personal and cultural identity - value of personal and cultural identity
-> Social responsibility - value of connecting with and caring for others
-> Historical and education - value of understanding one’s place in the world
-> Biophilia - value of connecting with nature
-> Aesthetic - value of beauty, wonder, and inspiration
What are the 4 main types of ecosystem services?
- Provisioning
- Regulating
- Cultural
- Supporting
What is provisioning as a type of ecosystem service?
Products obtained from ecosystems
- food
- water
- raw materials
- medicines
- biotechnology
What is regulating as a type of ecosystem services?
Benefits from regulation of ecosystem processes
- Air, water purification
- Climate regulation
- Soil fertility
- Erosion control
- Pest and disease control
- Pollination
- Natural disaster mitigation
What is cultural as a ecosystem service?
Nonmaterial benefits obtained from ecosystems
- Recreation
- Ecotourism
- Health and well-being
- Spiritual and religious
- Aesthetic and inspiration
- Educational
- Cultural heritage
What is supporting as a ecosystem service?
Ecological processes that control the functioning of ecosystems and production of all other services
- Resource capture
- Biomass production
- Decomposition
- Nutrient recycling
What is free market?
Prices for goods/services are self-regulated
Who is a free market determined by?
- buyers and sellers negotiating in an open market
- free from governmental regulation
What are free markets prone to?
externalities
detrimental effects of a business practice that are born by the public
Example of The problem of Free Markets
E.g. 1952 Great Smog of London killed ~12,000 people with 100,000 people suffering health effects
Today, over 9 million people die from pollution-related diseases each year; 16% of all deaths worldwide - more deaths than caused by wars, obesity, smoking, and malnutrition combined
<5 million Covid deaths in 18 months
What other externalities occur?
- Who pays for the costs of climate change?
- Or plastic pollution?
- Or the breakdown of ecosystems?
What do externalities lead to?
market failures that cause resources to misallocated:
- a few individuals or businesses benefit at the expense of larger society
Causes society to be less prosperous
Case Study 1: Wetland loss and Hurricane Katrina (2006)
- predicted in 1998
- loss 4877 km2 of wetlands removed the buffering from hurricanes
- New Orleans almost 5 m (14 feet) below sea level
- 2012 (6 years after Hurricane Katrina), state released master plan for the coast w/ cost of $50 billion over 50 years in full. $17.9 billion, is dedicated to wetland restoration
Case Study 2: How New York keeps drinking water clean
- clean water piped in from Catskill Mountains since 1830
- BUT agricultural intensification led to increase pollution
- cost of building treatment plant were prohibitive ($4 billion for initial construction and $200 million annually to operate)
- Instead, worked with Catskill Mountain farmers ‘Whole Farm Planning’ creating an individual plan for each farm to incorporate the environment
Huge success: - 95% of farms participated (despite being voluntary)
- 75-80% reduction in farm pollutants
