T4 Biodiversity and Natural Resources Flashcards
How has biodiversity over time become threatened by human activity?
-human activities have threatened many species with extinction
-improved technology has led to more food so birth rate increases
-improved medicine, hygiene and health care decreases death rate
-as human population increases, there’s more demand for natural resources
-this has a harmful effect on atmosphere and climate and therefore aquatic and terrestrial ecosystems
-this negatively impacts species and habitats within them
Factors that affect biodiversity are
-habitat destruction (coral reefs, sea beds, land clearing for human needs/wants like housing and agriculture)
-over exploitation (of fish stocks, deforestation)
-hunting (wild species hunted at a faster rate than their replenishment)
-agriculture (eutrophication and pesticides kill insect and aquatic species, hedgerows being removed)
-climate change
Define biodiversity
range and variety of genes, species and habitats within an ecosystem
it’s assessed at:
-the number and range of different ecosystems and habitats
-the number of individuals in each species (species evenness)
-the number of species and their relative abundance (species richness)
-the genetic variation within each species
Explain how biodiversity can be measured within a habitat.
-species diversity can be measured by species richness in a habitat (no. of species in community)
species evenness + species diversity = biodiversity
-for larger areas, representative samples of the area can be used to estimate the total species number
RANDOM SAMPLING
- takes into account distribution and abundance
-use of quadrats which are placed on ground
-organisms within them are recorded
-can be used with plants
-laid randomly to avoid sampling bias
-calculate percentage cover
FOR ANIMALS
-sweeping net - catch flying insects and those that live in grass, sweep net back and forth
-pitfall traps - jars buried in ground to catch insects in ground and invertebrates
-kick-sampling - catch freshwater invertebrates. stream bed is kicked and insects are carried by stream into the net
What is a niche habitat?
Niche - the {role/position} of a {species/organism} within the {ecosystem}
habitat - is the place where an organism lives while a niche is that organism’s role within that environment.
-a niche can only be occupied by one species so every species has a unique niche
-competition occurs if two species have the same niche and one will go extinct as it would be out-competed
Explain how biodiversity can be compared
in different habitats using a formula to
calculate an index of diversity.
Index of diversity - measurement that describes the relationship between the number of species present and how each species contributes to the total number of organisms that are present in that community
D = N(n-1) / Σn(n-1)
Where:
n = total no. of organisms for a single species in the community
N = total no. of organisms in the community
Σ = sum of
Larger number (D) = higher diversity level
-useful for comparing species diversity in different habitats
Give examples of behavioural,
physiological and anatomical adaptations of
organisms to suit their environment.
-adaptations occur because of abiotic and biotic selectors pressures
-they increase chances of survival and reproduction
Anatomical - structural features eg. horns, feathers, claws
Behavioural - courtship of defensive behaviours, migration, hibernation, distinct modes of communication
Physiological - processes inside the body, venom production, cellulose digestion
How does natural selection lead to
adaptation and evolution?
- there is variation in a population. this may be due to genetic mutations in DNA, that may be random, which introduce new alleles into a population. this means members of the population have beneficial alleles.
- Environmental factors act as a selection pressure for the population eg. predation, disease, competition
- Selection pressures increase the chances of those with a specific phenotype and with beneficial alleles surviving.
- Beneficial, advantageous allele are passed on and inherited by offspring
- Over many generations, the allele frequency changes, and a new species evolves through natural selection
- Individuals that do not possess the advantageous alleles will most likely not survive long enough to reproduce, therefore reducing competition for resources. This will decrease the frequency of these non-advantageous alleles over time in a population
How can reproductive isolation lead to
variation in populations and possibly the
formation of a new species?
-speciation can occur when populations of a species become separated from each other by geographical barriers
-the barrier could be natural like a body of water or man-made like a road
-this creates two populations of the same species who are reproductively isolated from each other, and as a result, no genetic exchange can occur between them
-if there are sufficient selection pressures acting to change the gene pools (and allele frequencies) within both populations then eventually these populations will diverge and form separate species
-Over time, the two populations may begin to differ physiologically, behaviourally and anatomically
Describe the process of classification
-domains are the highest taxonomic rank
-species is the lowest taxonomic rank in the system.
-there are no overlaps between the taxa
Domain > kingdom > phylum > class > order> family > genus > species
species concept - different species with similar phenotypes and genotypes can have the same genus but they aren’t the same species, as they don’t produce fertile offspring
-advances in tech have made it easier to compare organisms genotypes and explain the evolutionary relationships between them
describe molecular phylogeny and what it tells scientists
phylogeny - relies on similarities and differences of molecules (like DNA, RNA and proteins) between groups of organisms to see how closely they’re related
-the more similar the molecules, the more recent the common ancestor they share
What are the similarities and differences
between plant and animal cells?
SIMILARITIES
-mitochondria, endoplasmic reticulum, ribosomes, Golgi apparatus, cytoplasm
-membrane bound nucleus
DIFFERENCES
-Animal cells are primarily round and irregular in shape, whereas plant cells typically have fixed, rectangular shapes.
-Plant cells contain chloroplasts, whereas animal cells do not.
-Plant cells have a cell wall composed of cellulose in addition to the plasma membrane, whereas animal cells only contain a thin plasma membrane.
-Animal cells are equipped with a centrosome and lysosomes, whereas plant cells are not.
-Plant cells have plastids and a large central, permanent vacuole, whereas animal cells do not.
how would a scientist validate their research?
-peer review
-dedicated scientific journals
-scientific conferences
-is the paper valid?
-is the paper significant? (it has to add something to scientific knowledge)
-is the paper original?
What are the differences in the structure of
starch and cellulose, how does this relate to
their function?
-starch has a branched component, called amylopectin, which has 1,6 glycosidic links, whereas cellulose is straight chain
-cellulose has only 1,4 glycosidic links
-every other glucose is inverted to form the glycosidic links in cellulose
-hydrogen bonds hold the chains together to form cellulose microfibrils
-starch is made of alpha glucose and cellulose is beta glucose
describe how xylem structure relates to its function
- lignified cell wall
- adds strength to withstand hydrostatic pressure so vessels don’t collapse
- impermeable to water - no end plates
- allows mass flow of water and dissolved solutes
-adhesive and cohesive forces aren’t impeded - no protoplasm (cells are dead when mature)
- does not impede mass flow of water and dissolved solutes in the transpiration stream - pits in wall are non-lignified
- lateral water movement
- allows continual flow, in case of air bubbles in vessels - small vessel diameter
- prevents breakage of water column
- assists capillary action
describe the arrangement of cellulose in microfibrils in a plant
- cellulose molecules are unbranched chains of β-glucose molecules joined by 1,4-glycosidic bonds.
- microfibrils are formed from 50-80 cellulose molecules.
- hydrogen bonds form between adjacent cellulose molecules between adjacent hydroxyl groups and oxygen atoms.
- large number of hydrogen bonds give microfibrils their tensile strength.
Create a table outlining the similarities and
differences between sclerenchyma, xylem
and phloem vessels.
Outline the importance of water and
inorganic ions to plant.
-absorbed through the root hairs on the root and travel up the stem in xylem vessels
-plant cells perform a variety of different functions in order to perform these functions efficiently, the plant requires water and inorganic ions (minerals)
How could you investigate plant mineral
deficiencies ?
Outline an experiment to determine the
tensile strength of plants.
How has drug testing developed over time?
What conditions are required for bacterial
growth?
