Challenge 1 - The Biodiversity Crisis Flashcards
what is the overriding aim of Biol 1030?
to detail fundamental concepts so to understand causes and find solutions for the most important problems facing species today
Why is BIOL1030 important? KEY POINTS TO KNOW
Biodiversity and health of the planet impact upon every aspect of our lives.
>organisms are:
-primary sources of food, fuels, drugs, shelter and clothing
- agents of disease and death
- foundation of many cultures and beliefs and of immense aesthetic value
why do vertebrates feature predominately in highlighting the biodiversity crisis?
> Many are large and visible, small population size - easier to count/assess
higher trophic position in food webs - affected more by ecosystem disturbance?
humans have knowingly caused extinctions of vertebrates
of greater significance/value as a resource to humans
-food, clothing, perfumes
- economically important
- cultural/symbolic (totem, national symbols)
-aesthetic value
-evolutionary closer ties
- they can prey upon us?
what are the number of extinctions in Australia since european settlements?
27 mammals (7.5% of 257 species)
23 birds (approx. 3% of 800 species)
4 frogs
>100 plants
what is the significance of amphibians biomedicallly?
>pregnancy testing > production of medicines > use in assays > genetic studies >model for muscle disuse atrophy and starvation
what are the causes of amphibian number declines?
> habitat destruction/fragmentation, loss of breeding sites
increased exposure to ultraviolet radition (UV-B)?
global warming and climate change
insecticide use in agriculture (aerial spraying)
introduced species: can toad, mosquito fish
emerging disease
- chytrid fungus, damages keratin in skin
over-exploitation
enigmatic decline
How is the new ‘sixth mass extinction’ different from past events?
> happening over a very short period of time
rate of species loss 100-1000x faster than previous
created by one species modifying the plant - humans
What are the main threats to species?
> habitat loss, change and fragmentation >exploitation of species/resources >invasive/exotic species and emerging disease >pollution >environmental change
What is biological diversity?
> Sum total of life on Earth
the variety of all living things, the genetic information they contain and the ecosystems they form, which creates the complexity of life on Earth
“variation of life at all levels of biological organisation
What are the three levels of biodiversity?
> species diversity (variety of species)
genetic diversity (between populations, individuals)
ecosystem diversity (e.g., rainforest, desert , coral reefs)
what is species biodiversity?
> species diversity is the variety of species in an ecosystem or throughout the biosphere.
variety and number of species
What is richness a measure of?
the number of unique life forms, i.e., how many individuals of a certain species.
What is endemism and endemic species?
> species that are confined to a specific geographical region (species found nowhere else)
endemic species are often found in geographically isolated areas.
What is the difference between native species and introduced species?
Native = their presence in the geographic region is not due to human activity introduced = their presence is due to human involvement
what is a biodiversity hotspot?
biogeographic region with significant biodiversity and high endemism, which is under threat.
How do hotspots differ from megadiverse areas?
megadiverse = large amount of different species hotspot = large amount of different species that are highly threatened.
what are the criteria for biodiversity hotspots?
1) must contain at least 1,500 species of vascular plants (>0.5 % of the world’s total) as endemics
2) to have lost at least 70% of its original habitat
What is genetic diversity?
comprises of genetic variation within a population and between populations
What important roles does genetic diversity play in the survival and adaptability of a species?
> species with less genetic variation are at a greater risk
vulnerability of a population to disease can increase with reduction in genetic diversity
problems associated with inbreeding.
What is so special about genetic variation?
Genetic variation makes evolution possible - provides the raw material for evolutionary change.
what is an example of a species where low genetic variation has had a detrimental effect?
Tasmanian Devil.
> massive pop. declines - due to devil facial tumour disease - highly contagious
>little genetic variation within pop = everyone is susceptible.
what is ecosystem diversity?
> rainforests, desert, coral reefs
assemblages/communities of organisms: microbes, plants and animals (biotic) and the physical environment around them (abiotic)
inclusive of functional traits - nutrient cycling and energy cycling
what are ecosystem functions?
ecological processes in the environment that regulate the fluxes of:
>energy
>nutrients
> organic matter
what are ecosystem serives?
the suite of benefits that ecosystems provide to humanity.
>provisioning - production of renewable resources e.g., food, wood, oxygen
>regulating - those that lessen environmental change e.g., water/air purification, carbon sequestration, disease control
how does evolution describe the unity and diversity of life?
> organisms are modified descendants of common ancestors
similar traits among organisms are explained by descent from common ancestors
differences among organisms are explained by the accumulation of heritable changes
natural selection is the overriding mechanism
what did Darwin OBSERVE?
> individuals in a population vary in their traits, many of which are heritable
more offspring are produced then survive, and competition is inevitable
species generally suit their environment
What did Darwin INFER?
> individuals that are best suited to their environment are more likely to survive and reproduce
over time, more individuals in a population will have the advantageous traits
evolution occurs as the unequal reproductive success of individuals
What is radiometric dating?
radio active decay of isotopes
>to characterise past life reliant upon:
> fossils - preserved remains of organisms
> trace fossils - traces of life, e.g., footprints, coprolites
> fossil record - documents history of life
what are the three eons?
Archean
proterozoic
phanerozoic
what are the three eras of phanerozoic?
paleozoic
mesozoic
cainozoic
what are the periods in paleozoic?
cambrian
permian
triassic
cretaceous
what were the first cells?
> heterotrophs that fed on organic molecules
>anaerobic fermentation (anaerobes) process to obtain energy
what happened in the paleozoic era?
> begins with the Cambrian explosion
arise of the many new forms of life, including the vertebrates
fishes diversity
colonisation of land - plants, simple animals and vertebrates
appearance of the reptiles
at the end of the paleozoic, the continents were joined into a single land mass, pangea
ends with a mass extinction event - “the Permian Extinction”
What happened in the Permian extinction?
> 251 million years ago
the largest madd extinction event in earth’s history
large lava eruptions, volcanic dust in the atmosphere
temperature drops
oxygen levels drop
buildup of hydrogen sulfide (produced by bacteria)
- > 95% of all species died out
what happened in the mesozoic era?
> 251 - 65 mil years ago
continental drift - split up Pangea, Laurasia and Gondwana - promoted speciation as a consequence of geographical isolation.
age of the reptiles
large living terrestrial animals, the dinosaurs
what are the modern day representatives of the reptiles of the mesozoic era?
Tuatara, turtles, Squamates (lizards/geckos and snakes), crocodilians
what happened in the cretaceous extinction ?
65 million years ago
> 75% of species lost
>dinosaurs disappeared.
What happened in the cenozoic era?
> mass extinction heralded the start of the current era
stared 65 million years ago, continues to present
mammals became the dominant life form on land. An adaptive radiation that took advantage of the sudden loss of dinosaurs.
another large group evolves : grasses
adaptive radiation of birds and flowering plants
what are the modern representatives of the cenozoic era?
Endothermy (internal heat source) > many characteristics of birds are adaptions that facilitate flight > wings > no urinary bladder > females with only one ovary > loss of teeth
what are some adaptations used for flight?
wings, feathers, hollow bones, reduced body mass, lungs
what are the three major linages of the mammals?
> monotremes (egg laying)
marsupials (pouches)
placentals (complete development in uterus)
what are the modern amphibians?
> representation of transition to land >requirement to maintain ties with water >aquatic and terrestrial existence >moist skin - prone to desiccation > eggs - no protective covering to reduce desiccation
what animals are in the amniotes?
Reptiles, birds and mammals
What are amniotes?
> appeared in Paleozoic
reptiles earliest form of amniote
scales (layers of keratin) - a waterproof barrier
shelled eggs (cleidoic)
stronger skeleton - improved locomotor ability, including bipedalism.
describe the first vertebrates
> first appeared in the fossil record during the cambrian explosion
had a basic fish-like body plan - wiyh an internal axial skeleton, based around skeletal rod (notochord)
were jawless
filter feeders
what are the modern representatives of the agnathans?
> hagfish
>lamprey
describe the jawed vertebrates
> mid-paleozoic - appearance of jaws and appendicular skeleton
added ability to chew and grind
changed from essentially a tube to somethng with arms and legs
good examples in fossil record of 1st jawed fish
diversification/radiation of “the fishes”
what were the significant evolutionary innovations of the jawed vertebrates?
> greater diversity in body shape and size
new feeding modes
new modes of swimming /better control
wwhat is the name given to the age of the fishes?
Devonian - a mass speciation event
Describe the chondrichthyes
>the cartilaginous fishes >sharks, rays, skates, ratfish and sawfish >impressive diversity >fusi form > apendicular skeleton > whale shark
Describe the Actinopterygii
>ray - finned fishes > bony endoskeleton > > 30000 species > vast array/ diversity of body shapes and sizes > huge biomass > golden snapper > bill fish/marlins > eels - appendicular > stone fish - locomotion (pectoral) > Pectoral fish can contain poision
describe the first land vertebrates
> colonised the land
fins evolved into the limbs
strengthening of pectoral and pelvic girdles
support weight of body on land
describe the Sarcopterygii
> fleshy finned
lobe-finned fishes
- the coelacanth
- the lungfishes
- presence of muscular pectoral and pelvic fins, supported by extensions of body skeleton
link between fishes and land vertebrate
crawling motion instead of scullying.
evolution of lungs
significant event in vertebrate evolution
diverticulum of the oesophagus
what are the three main groups of modern amphibians?
> Anurans (no tail) - frogs and toads
Caudata (tailed) - salamanders and newts
apoda - caecillians
what is one of the most significant evolutionary steps in the history of life?
multicellularity evolved independently several times in the eukaryotes
what are the advantages of multi-cellularity?
1) protection against predation - large size
2) improved attachment to surfaces
3) greater buffering against environmental fluctuations
> multicellularity allows for entirely new levels of organisation
What are the unicellular ancestors of modern day groups of organisms?
Chlamydomonas = plants yeast = fungi Choanoflagellates = animals
what happened in the Cambrian explosion?
> about 540 myr sudden appearance of large numbers of multicellular organisms
Broad selection of body plans. Some unrelated to present-day life forms.
some body plans disappear completely
heralded the start of the paleozoic era
what are some examples of organisms that formed during the Cambrian explosion?
> Sponges >Anemones, jellyfish and coral > flatworms >snails, bivalves, cephalopds > crustaceans, insects, spiders and mites
what happened in the Paleozoic era? (542-250myr)
> Starts with the Cambrian explosion, ends with the Permian Mass Extinction (250 myr ago)
early Paleozoic dominated by marine invertebrates
colonisation of the land (plants and animals)
appearance and evolution of vertebrates (fish) early-mid Paleozoic
What are the challenges of living a terrestrial existence?
> desiccation
UV radiation
Gravity
Thermal Fluctuations
How did plants colonise the land?
Needed to evolve:
>the ability to stand upright and transport nutrient against gavity
> a cuticle (waxy coating) to conserve water
> a vascular system to take in water
What are non-vascular plants?
> Bryophytes - mosses, liverworts
What are some vasular plants?
Vascular plants
>ferns
>gymnosperms
>angiosperms
Why is biodiversity important?
Utilitarian values of individual species
>economic value
> ecotourism
What is an example of an organism that helps people?
sandcastle worm - water-borne underwater adhesives (bioengineering)
What identifies an animal or Metazoa?
1) digest food INSIDE body
2) No cell wall - use structural proteins
3) MOST have muscles and nerves = movement
> Animals ingest food then use enzymes to digest it inside their body, but outside their cells, e.g., stomach or tube
>non-animals either digest food outside their body eg plants, protists
What identifies an invertebrate?
1) absence of notochord
examples: sponges, comb jellies, coral, sea stars, flat worms, molluscs
what identifies an arthropod?
1) exoskeleton
2) Segmented body
3) jointed appendages
What are some organisms that have economic value ?
Ants and wasps ants butterflies leaf hoppers glow worms
What characterises the class insecta?
1) Chitinous exoskeleton
2) three part body (head, thorax, abdomen)
3) Three pairs joined legs
4) compound eyes
5) one pair antennae
What is an insect?
> variety of lifecycles, but all undergo metamorphosis by either: 1) complete metamorphosis has 4 stages (eggs, larvae, chrysalis, adult)
2) Incomplete metamorphosis = gradual change through series of molts.
What is an ecosystem made up of?
> ecosystems comprise of abiotic and biotic components
What are some examples of provisioning ecosystem services?
> food >medicines and drugs >energy > Oxygen >Biochemicals >Genetic resources > Ornamental resources
What are the 4 ecosystem services?
Provisioning
regulating
supporting
cultural
what is a regulating ecosystem services?
Those that lessen environmental change example: > air quality regulation > carbon sequestration > climate regulation > water regulation and purification >erosion control > disease regulation > pollination
what are some examples of air quailty regulation?
> plants remove pollutants from air
plants on the side of the road
dampen the effect of infastructure
Microbial immobilisation of sulphur
What characterises a bacteria?
1) prokaryotic cells
2) cell wall
3) Molecular structure e.g., peptidoglycan (distinct from archaea) .. antibotics often target peptidoglycan.
what are some examples of climate regulation?
> sequestration of greenhouse gases in trees
land cover can influence local temperatures and rainfall
ocean phytoplankton has absorbed approx. half of human produced CO2 since industrial revolution
What are some examples of water regulation and purification?
> vegetation and micro-organisms remove pollutants from the water
naturally vegetated watercourses limit flooding
wetlands purify water.
What are some examples of erosion control?
> naturally vegetated watercourses show minimal erosion compared with cleared watercourses
mangroves and reefs prevent coastal erosion
what are some examples of disease regulation?
> insects and other predators naturally control disease carrying insects
mosquito fish
what are some examples of pest regulation?
> predation of pest insects by native animals
predation of house mouse by native carnivores
biological control
What are some examples of pollination regulation?
> insects, birds, and mammals pollinate crops and native plants species that are used by people
bat, insects, birds, hang possum
What makes a plant different from other eukaryotes?
1) apical meristems
2) Alternation of generations
3) walled spores
All plants
>photosynthesis
> are multicellular
What is it meant by apical meristems?
Growth zones of roots and shoots > part of the plants where it grows > every species has one in a different spot > grows like brick wall - linear >can have multiple >unique to plants
What is it meant by alternation of generations?
> plants alternate between two multicellular bodies which usually look totally different from each other. Size of generations varies dramatically.
gametophyte(n) and sporophyte (2n)
what is it meant by walled spores?
desiccation resistant - an advantage for land where desiccation may be a problem
>spore = single cell
>key to success
>enter harsh environments
what is an example of ecosystem functions/ supporting services?
> soil formation >photosynthesis >primary production >nutrient cycling >water cycling
describe soils formation
> the organic component of soil comes from biodiversity - holds the most nutrients needed by the plant
the organic component of soil is created through decomposition (the metabolic breakdown of materials into simpler components by living organisms)
What characteristics do fungi and plants share?
> cell walls
develop by progressive growth (brick wall) diff. animals
reproduce both sexually and asexually
produces spores (same as mosses and ferns)
what do fungi and animals share?
> both digest outside their cells
fungi use the area around them outside their actual body to suck up the nutrients and then move once they have fully depleted the area
what are mutualists?
90% of plants require symbiosis with a mycorrhizal fungi to survive.
>the tiny filaments encase and extend from the roots, dramatically increasing the plant’s ability to collect moisture and nutrients .
describe photosynthesis and give examples
Photosynthesis: primary production
> provides the basic building blocks for all carbon-based life forms. Almost all life on earth is directly or indirectly reliant on primary production.
>natural vegetation and algae replenish the oxygen we breathe and require for energy use.
What is the difference between a heterotroph and an autotroph?
autotrophs use CO2 to make energy while heterotrophs use organic compounds often found in soil.
describe water cycling and give examples
> transpiration transfers ground water to the atmosphere
>role of plant transpiration in controlling soil salinity
describe nutrient cycling and give examples
> symbiotic bacteria in many plants fix nitrogen from the atmosphere, thus fertilising the soil
biodiversity recycles natural materials such as mineral nutrients e.g., C, N, P, S, Ca, Mg, K, Na and water
highly important
availability of nutrients
gaseous –> non-gaseous
involves biodiversity - microbes
describe the biodiversity in soil
1g of soil has enormous biodiversity, incredibly important in the nutrient cycle.
What are the steps of the water cycle? also know the diagram
> fresh water is circulated through the processes of evaporation, condensation and precipitation. Also include evapotranspiration, runoff, high groundwater flow and bedrock
what identifies Archaea?
1) membrane structure
2) biochemicals used in metabolism
What are the three examples of extremeophiles?
halophiles = extreme salinity Thermophiles = Extreme temperatures Methanogens = produce methane gas during metabolism
in what circumstances can biodiversity be negative?
> pathogen diversity
drug resistance bacteria diversity
biodiversity and biological control
how does biodiversity support farming profit?
healthy soils water retention pollination water cycling nutrient cycling pest control
what is a biodiversity hotspot?
biogeographic region with significant biodiversity and high endemism, which is under threat.
how are species related to taxonomy?
species are the fundamental taxonomic units of biological classification.
>environmental laws are framed in terms of species
> even our conception of human nature is affected by our understanding of species.
What is the biological species concept?
members of populations that are actually or potentially interbreed in nature and produce viable, fertile offspring
> What about asexually producing organisms?
What are ring species?
species that move to different locations and thus over time develop into subspecies that can’t always interbreed
what does speciation depened on?
reproductive isolation. Pre-fertilisation > habitat - sea v land snake > timing - day/night, season >behaviour - mating song >mechanical - genitalia >Gamete - sea urchin proteins Post - fertilisation > Reduced hybrid viability >reduced hybrid fertility > hybrid breakdown - cultivated rice.
what is the morphologicl species concept and the pros and cons of it?
identify by body shape and other structural features. most commonly applied in the field.
Pros:
> applicable to asexual and sexual organisms
> do not need to know gene flow or life history
> applicable in field and collection situations
>knowledge of behaviours or ecology not required.
Cons:
>relies on subjective criteria –> difference of opinion
>mimicry
what is the ecological species concept? give pros and cons
views a species in terms of ecological niche, i.e., the sum of how they interact with living and non-living parts of the environment.
Pros:
>applicable to asexual and sexual
>emphasises role of adaptation to different environmental conditions
Cons:
>requires knowledge of organism in it natural environment
what is the phylogenetic species concept? give pros and cons
the smallest group of individuals that share a common ancestor, forming one branch of the tree of life.
Pros:
>accurately reflects process of evolution
?relies on morphological and genetic information
Cons:
> how different do they need to be to be considered different species?
>comprehensive information is usually not available and expensive to obtain.
how do you choose which species concept to go with?
depends on the situation, research question being asked and intended purpose.
what is a cline species?
a form of species that exhibit gradual phenotypic and/or genetic differences over a geographical region. Ring species are a distinct type of cline.
how do some species go extinct because of introduced/ invasive species?
from mating with the invasive species, forming hybrids, that can no longer interbreed with the original species, therefore making the original species extinct.
>examples: rainbow trout x cutthroat trout
> mallard duck x New Zealand gray duck
Sika deer x red deer
what is phylogenetics?
the study of genetic and morphological relationships among groups of organisms
>how similar or different is the DNA and other characteristic of two or more organisms?
describe the makeup and components of phylogenetic trees
Branches
>represent the evolution of OTUs over time
Three Operational Taxonomic Units
>OTU’s can represent species, individuals, genomes, genes or other entities that have evolutionary histories
Nodes
>represent the points at which one evolutionary lineage separated into two. Nodes represent the common ancestor of the OTUs above the node.
what is evolution?
The change in DNA and associated heritable characteristics of a population of organisms over time.
how does reproductive time affect conserving and managing biodiversity?
longer time to reproduce, i.e., less organisms being born, i.e., longer to evolve.
