Biodiversity and Natural Resources Flashcards
Define biodiversity
The variety of living organisms in an area
What are the two ways of measuring biodiversity?
1) Species richness - Number of species in a habitat
2) Genetic diversity - Measure of genetic variation in a species, or the number of alleles in a gene pool
How do you calculate the heterozygosity index?
Number of heterozygotes/total individuals in population
What is the formula for biodiversity index?
D = [N(N-1)]/∑n(n-1) D = diversity index N = total number of organisms n = total number of organisms of each species
Define endemic
When a species is unique to a particular geographic location
Define niche
The role of a species in a community, and its interaction with biotic and abiotic factors
What are the 3 types of adaptations?
Anatomical adaptations: Structural adaptations (external or internal), e.g. thinner beak of finch to hunt for insects
Behavioral adaptations: Changes in behavior that improve the organisms’s chance of survival, e.g. mating calls
Physiological adaptations: Internal processes that increase chance of survival, e.g. blood flow regulation through skin
Explain natural selection
Fitter individuals more adapted to the environment have a better chance of survival, so can pass on advantageous alleles to future generations
Explain the process of evolution
A variety of phenotypes exist in a population due to random genetic mutation.
An environmental change occurs, leading to a new selection pressure.
Individuals with advantageous alleles give them a selection advantage, allowing them to survive and reproduce.
Advantageous alleles are passed to offspring, over time increasing frequency in the population.
What is the Hardy-Weinberg equation?
Used to estimate allele frequency in a population and monitor changes.
p^2 + 2pq + q^2 = 1
p^2 = dominant homozygous frequency (AA)
2pq = heterozygous frequency (Aa)
q^2 = recessive homozygous frequency (aa)
What are the conditions for the Hardy-Weinberg equation?
No mutations Random mating Large population Isolated population No selection pressure
What is likely to occur when populations become isolated from one another?
New species will be formed due to accumulation of different genetic information in populations over time due to different environment and selection pressures
What is allopatric and sympatric?
Allopatric - When groups of organisms are geographically isolated
Sympatric - When groups of organisms are isolated by other means, in the same area
Explain the binomial system of classification
Homo sapiens
genus - species
How are organisms classified?
Kingdom, phylum, class, order, family, genus, species
What is molecular phylogeny?
The analysis of molecular differences in organisms to the extent of their evolutionary relationship
What is the three domain model?
Bacteria, archaea, and eukaryota
How does the scientific community evaluate data?
Peer review of data of evidence, then publishing in scientific journals, where they are presented at scientific conferences
Name 3 organelles present in plant cells and not in animal cells
Chloroplasts
Pits
Plasmodesmata
Name another 3 organelles present in plant cells and not in animal cells
Cell wall
Amyloplasts
Vacuole
Describe the function and structure of chloroplasts
Chloroplasts - Site of photosynthesis, bound by a double membrane called the envelope. They contain stacks of thylakoid membranes called grana, containing chlorophyll. Grana are connected by extensions of thylakoid membranes called lamellae, and are surrounded by a fluid called stroma, containing enzymes for photosynthesis.
Describe the structure & function of:
Amyloplasts
Pits
Cell wall
Amyloplasts - surrounded by double membrane, contain amylopectin (starch) for storage, convert starch to glucose when required
Pits - Thin sections of cell wall which allow transport of substances between adjacent cells
Cell wall - Made of cellulose. Cell wall is made up of middle lamella, which is made of calcium pectate and holds adjacent cells, cellulose microfibrils and microfibers together
Describe the structure & function of:
Vacuole
Plasmodesmata
Vacuole - Contains cell sap and is surrounded by a tonoplast (single membrane), providing cell support and strength
Plasmodesmata - An extension of cytoplasm between the cell wall of adjacent cells involved in transport of substances
Define carbohydrate
Molecules which contain carbon, hydrogen and oxygen only
Describe the structure of cellulose
Made of long, unbranched chains of beta glucose joined with glycosidic bonds. Microfibres formed of microfibrils are strong threads of long cellulose chains, joined together by hydrogen bonds for structural support.
Describe the structure & function of xylem vessels
Transport water and minerals, also providing structural support. Long cylinders of dead cells with open ends, strengthened by lignin
Describe the structure & function of phloem vessels
Tubes made of living cells involved in translocation of nutrients and food substances from leaves to storage organs
What are cambium cells?
Cambium cells between xylem and phloem are undifferentiated and can specialize as the plant grows
Describe the structure & function of sclerenchyma fibres
Short structures of dead cells with hollow lumen and end walls. Strengthened with lignin and provide structural support
Describe the structure & function of parenchyma cells
Act as packing between other cells and vessels
Describe 5 ways plant fibers can be used as a resource
Plants are a renewable resource, biodegradable, strong for use in rope or fabrics, cheaper production than oil-based, can be used in bioplastics/bioethanol
Why is water needed in plants?
Water is required for: Structural rigidity Photosynthesis Transport of substances Thermoregulation
What are magnesium ions used for in plants?
They are involved in chlorophyll production and activate some plant enzymes
What are nitrate ions used for in plants?
Supply nitrogen to produce DNA, RNA , and chlorophyll
What are calcium ions used for in plants?
Component of cell wall, form calcium pectate, also essential for plant growth
Explain the 3 stages of contemporary drug testing
Phase 1 - The drug is tested on a small group of healthy volunteers to test for dosage and toxicity
Phase 2 - The drug is tested on a large group of patients with the condition to test for efficacy
Phase 3 - Drug is tested against pre existing drugs with double-blinded trials to test for the placebo effect
What is in-situ and ex-situ conservation?
In-situ is conservation in an organism’s habitat, ex-situ is outside an organism’s habitat
Describe the method and pros of seed banks
Seed banks - Storage of a large number of seeds to conserve genetic diversity and prevent extinction. Since seeds are stored, less space is used and a larger number of species can be stored. They must be stored in cool, dry conditions and are periodically tested for viability
Explain the method of captive breeding programs
Endangered species are bred to increase genetic diversity and population size via stud books, exchange of gametes, prevention of inbreeding, and IVF. Followed by reintroduction programs.
Explain two in-situ methods of conservation
Education programs - aim to educate people about the importance of maintaining biodiversity, captive breeding programs and illegal trade of animal products.
National parks and Sites of Specific Scientific Interest aim to conserve habitats and biodiversity.
