Bio Ecology And Plant Repro (missing Case Studies) Flashcards
Abiotic vs biotic environment
Physical factors , living things organisms interact with
Abiotic enviro factors
- light intensity
- temp
- pH
- salinity
- oxygen
- water
Abiotic: light intensity
- affects distribution and growth of plants and animals
- growth of certain plants affects animal distribution
Abiotic temperature
- affects physiological and metabolic activities of organisms : affects rate of reaction of enzymes
- eg snakes hibernate in winter: lower rate of enzymes reactions
Abiotic: pH
- Most organisms survive a range of oH
- acidophiles: microorganisms that thrive in acidic conditions
- eg blueberry and orchids prefer acidic soils
Abiotic: water
- availability factors: amt and pattern of rainfall, air humidity
- need water to live; where water is scarce, orgs adapted for survival
Abiotic: oxygen
- needed for aerobic respiration
- eg mangroves roots in oxygen poor mud, thus breathing roots that project above mud surface
Abiotic: salinity
Eg fish
Freshwater: salt loss, excess water. Uptake of salt in gills, kidney reabsorbs more salt, dilute urine
Saltwater: water loss, excess salt. Seawater absorbed in intestines, kidney excretes little salt, conc urine
Energy and nutrient flow P-C-D
Producers
Convert light e from sun into Chem e in food
Consumers
Obtain e by feeding on other orgs
decomposers
Obtain e by breaking down dead orgs, faeces, excretory products. Releases inorganic nutrients (carbon, nitrogen)
Food chain
Series of orgs thru which energy is transferred in the form of food
Grass ——-> grasshopper—> toad —…
(Producer) (pri cons) (Sec cons)
Food web
Consists of interlinked food chains
. —> caterpillar ————
. | v v
Green plant —> grasshopper—> spider
. | ^
. —> aphid ——————-
———> ladybug
Non cyclic energy flow
- sun is main source
- light e to Chem e by producers via photosynthesis
- energy from lvl to other via feeding
- energy lost: heat (respiration), uneaten parts, dead bodies, faeces
Pyramid of numbers
No of organisms at each trophies level
(Can be inverted if orgs are parasitic/ many small on large)
. __
. _______
_________
Pyramid of biomass
Comparison of mass of orgs (dry mass: mass of dead, dry body)
May look odd if one org has high repro rate
Pyramid of energy
Total energy in each tropic level
- energy lost to surroundings as food transferred from one tropic lvl to another
- approx 90% e lost from each tropic level
Loss of energy to environment when passing thru tropic levels
- heat during respiration
- uneaten body parts
- undigested matter egested
- waste products excreted
Nutrient cycling
- brought about by physical, chemical, and biological processes
- involves both biotic and abiotic
The carbon cycle
The carbon cycle
- carbon continuously removed and released into Atmos as CO2
- relatively consistent CO2 conc (~0.03%)
Importance: - ensures continuous supply for photosynthesis
- enables energy flow thru ecosystem
Carbon cycle co2 removal
Photosynthesis
- green plants take in CO2, used to prod carbon compounds
- feeding: carbon compounds stored in animals bodies
- fossil fuel: carbon compounds may be preserved
Carbon cycle co2 released 3
Respiration
- carbon compounds eg glucose broken down into co2
Combustion
- fossil fuels release co2
Decomposition
- organisms die, dead matter broken down into simple substances eg co2 by decomposers
Carbon sinks (oceans and forests)
Area that stores carbon conoides for indefinite period, stores more than releases
Oceans:
- largest CS on earth
- co2 dissolved in water and used by phytoplankton and algae in photosynthesis
- portion buried in seabed as fossil fuels
Forests:
- co2 in Atmos absorbed by plants for p.sis
- large and of carbon compounds stored in trees
- remains for dead trees form coal (fossil fuel)
Renewable vs non renewable natural resources
can be replaced by natural cycles if not overused , cannot be replaced
effects of deforestation 4
- soil erosion
Forests, leafy canopy prot topsoil from direct rain impact, retain water. w/o, topsoil easily washed away - flooding
Rain> soil erosion> soil washed into river> ^water level> ^chance of flood - desertification
Direct sunlight on ground> water evap
Desert like condition= X plant growth - climate changes
Less plant life > less co2 removed from Atmos via p.sis
Co2 GH gas > traps heat in earth atmos > warmer climates
Overfishing (uncontrolled practices) techniques and effects
^ human population, ^demand for fish
Results in reduced aquatic biodiversity
- dredges : destroys sea bed orgs eg coral reefs
- drift nets and trawlers : catch marine life indiscriminately
- cyanide fishing : kills coral and other reef orgs
- destruction of marine habitat
- decr and extinction of certain fish populations
Pollution def
Process where harmful substances are added into enviro
Water pollution 3
- sewage
waste mats from homes and industries, untreated: disease-causing bacteria, can cause epidemic if discarded in water bodies - Chem fertilisers
Contain nitrates and phosphates
Excessive leads to eutrophication - inorganic waste
Chemicals that cannot be excreted passed along food chain
Bioaccumulation and bioamplification
Harmful substances that cannot be excreted passes thru food chain, accumulating in bodies (bio acc) of final consumers (bio amp)
Eutrophication
Excess fertilisers not absorbed by crops washed into lakes
v
Nutrients in fertilisers incr growth of water plants and algae on lake surface
v
Submerged plants die from lack of sunlight (bacteria grows rapidly using up dissolved o2 as they decomp)
v
Other orgs die from lack of O2
Conservation def
The prot and preservation of earths natural resources
Reasons for conservation 6
- scientific value (studies on wildlife give insight on humans)
- maintenance of a balanced ecosystem
- maintenance of biodiversity (preventing extinction, maintaining large gene pool)
- economic importance : rainforests source of raw mats
- food source: marine life
- preservation of natural scenery and wildlife
Wastewater treatment (environmental biotech)
- Wasted water channeled into water reclamation points
- WW enters primary settling tank: heavy solids settle to bottom, removed as sludge
- Partially treated WW transferred to aeration tank, mixed with bacteria which breaks down organic pollutants into harmless substances
- WW sent to final settling tank, bacteria removed
- Treated WW discharged into sea
- Sludge removed from settling tanks, treated in anaerobic digesters. Dewatered and disposed in soil container
Measures to conserve forests
- creation of laws to regulate logging industry
- reforestation: planting trees
- designation of land : forest reserves
- research > improve quality of forests
Measures to conserve fishing ground
- banning sue of drift nets trawlers and dredges
- nets with certain mesh size -> young fishes not caught
- limiting no of fish caught
- raising endangered species in hatcheries for release into sea
Asexual repro
Results in genetically identical offspring ; clones
No fusion of gametes
Daughter cells same no of chromosomes , type and amt of genes
Sexual repro
Fusion of 2 haploid gametes = diploid zygote
Genetically dissimilar offspring
Daughter cells half of chromosomes
Parts of a carpel/pistil (F) 7
- stigma
- style
- ovary
- definitive nucleus
- ovule
- placenta
- funicle
- placenta
Parts of a stamen (M)
- anther
- filament
Stigma
Revives pollen grains
Mature: secrets sugary fluids to stimulate pgrain germination
Style
Holds stigma at position to trap pgrains
Ovary in flower
Devs into fruit after fert
Produces and protects 1 or more ovules
Ovule in flower and subparts
Ovule
- Contains ovum
Via stalk called funicle
Attached to placenta
Anther
Produces pollen grains
2 lobes, each 2 pollen sacs
Pollen grain components 2
- 1 make gamete (generative nucleus)
- pollen grain nucleus
Filament
Holds anther in suitable position to disperse pollen grains
Pedicel
Flower stalk
Receptacle
Enlarged end of flower stalk
Yknow that bulge that connects flower to stalk
Sepal (s) calyx (p)
Modified leaf, protects flower in bud stage
Petal (s) Corolla (p)
Insect pollinated flowers are brightly coloured to attract, serve as a landing platform
Pollination
Transfer of pollen grains from anther to stigma
Brings tgt m+f gametes for fert
Self pollination or cross pollination
Self pollination
INVOLVES FUSION OF GAMETES
=/= ASEXUAL REPRO
- transfer of pollen grains from same/diff flower of SAME plant
- flowers bisexual
- stigma directly below anther
Advantages of self pollination 5
- beneficial qualities from parents carried to offspring
- only one parent req
- less pollen and energy wasted
- more likely for stigmas to be closer to anthers
- not dependent on external actions
Disadvantages of self pollination
- offspring are genetically similar (not identical) -> fewer varieties
- higher probability of expression of harmful recessive alleles
Cross pollination
Transfer of pollen grains from anther to stigma of flower of ANOTHER plant
- either dioecious (m or f) or bisexual (can self pol, cross when S and A nature at diff times, S too far away)
Advantages of cross pollination 4
- offspring inherit beneficial qualities from both parents
- more varieties -> more genetic variation
- seeds survive longer before germination
- more prob of heterozygous offspring
- lower prob of harmful alleles expressed
Disadvantages of cross pollination
- 2 plants of same species req
- dependent on external factors
- more energy and pollen wasted
- less likely to occur
Fertilisation in plants steps 7
- Pollen grain germinates in response to sugary fluid secreted by mature stigma
- Pollen tube grows from pollen grain
- Male gamete (gen. nucleus) enters ptube
- Ptube secretes enzymes, digests tissues of stigma and style, grows down style to ovary
- Ptube enters ovary via micropyle
- Tip absorbs sap & bursts, releases male gamete
- Haploid male gamete nucleus fuses with ovum to become diploid zygote (divides and devs into embryo)
Wind pollinated vs insect pollinated flowers 7
- Petals: small, dull coloured // large, bright colours
- Nectar: absent // present
- Scent: absent // fragrant, sweet
- Stigmas: large, feathery, protrude // small, compact, do not protrude
- Stamens (make chunk): pendulous, protrude // not pendulous, do not protrude
- Pollen: more abundant. Grains tiny smooth // fairly abundant. Grains larger rougher.
- Nectar guides: absent // present
