CAP 1 revision Flashcards
Biodiversity
The number of species and the number of individuals of each of the different species within one community
Species Richness
The number of different species within a community
Community
All the individuals of all the species living together in the same area at the same time
Species
Group of similar organism with the same genes that reproduce to produce fertile offspring
Genetic Diversity
Difference in DNA
Niche
Describes where an organism lives and what it does, including what it feeds on and how it interacts with other organisms and the environment.
Habitat
Place where organisms live in an ecosystem
What information is required to calculate an index of diversity for a particular community
Number of species, number of individuals in each species
the number of species present is one way to measure biodiversity. Explain why an index of diversity may be a more useful way to measure
also measures number of individuals of each species. some species may be present in low and high numbers.
2 advantages of using an index of biodiversity rather than an indicator species
you don’t need to identify each species, index considers the number of organisms of each species.
economic argument for maintaining biodiversity
medical/pharmaceutical use, commercial products, tourism, agriculture, saving local forest communities.
farming
Decrease in the variety of plants- fewer plant species. Fewer habitats, decrease in variety of food sources, clearing forest through machinery or pesticides.
Clearing a tropic forest for crops- why does this cause diversity of insects to decrease
lower diversity of plants, few food sources, few habitatas, fewer species of herbivore so few species of carnivores, kills insects
Taxonomy
Theory and practice of classification
Binomial naming system- first word= genus. second word= species name.
classification system:Domain, kingdom, phylum, class, order, family, genus, species
Phylogenetics- all share a common ancestor
courtship
display this behaviour to attract a mate of the same species of opposite sex. Important to ensure reproductive success.
1. Attracts same species of the opposite sex, indication of sexual maturity, stimulates release of gametes. form bond pair
modern classification methods
frequency of measurable or observable characteristics, the base sequence of DNA, base sequence of mRNA, amino acid sequence of proteins encoded by DNA and mRNA
Genetic comparisons and DNA
genetic- made by examination of their DNA, mRNA or of the proteins coded for by this DNA, classified within their genome.
DNA- the more closely related the species the more similar their DNA base sequence.
Comparing the base sequence of a gene provides more information than comparing the amino acid sequence for which the gene codes. Explain why
Longer base sequence than amino acid sequence. Introns, same amino acid may be coded for and a DNA code may be degenerate
Comparing base sequence provides more evolutionary information. Explain why
More bases than amino acids, introns, degenerate code
ATP
Adenosine Triphosphate- useful because it releases energy in small, manageable amounts, it’s broken down in one-step, immediate energy compound, phosphorylase’s, released instantaneously, rapidly re-synthesised.
Chloroplast
key structures of a chloroplast- lamellae joins thylakoid membranes together, stroma is where chemical reactions occur for photosynthesis, granum, thylakoid membrane, thylakoid space.
Light dependent reaction
Takes place in the grana and thylakoid membrane and results in the formation of NADPH and ATP
Chlorophyll absorbs light energy, chlorophyll becomes oxidised. Excited electrons move to a higher energy level- energy released helps activate the proton pump. Electrons move down ETC through a series of redox reactions. This pumps H+ ions, forming a proton gradient which moves through ATP synthase to combine ADP + Pi to form ATP. High energy electrons from the next chlorophyll reduces NADP to form NADPH. Photolysis- energy from light catalyses the breakdown of water forming 2H2O—> 4 protons, 4 electrons and O2. protons are used to help activate proton carrier and form a proton gradient. Electrons replace electrons lost from chlorophyll and reduce NADP.
Chemiosmotic theory
The movement of ions across a ,membrane down an electrochemical gradient. This gradient is usually established through REDOX reactions and activation of proton pump.
The light independent reaction
CO2 combines with RuBP, produces two GP molecules, 2GP reduced to 2 x Triose Phosphate, using reduced NADP and energy from ATP. Triose phosphate converted to glucose. RuBP reformed.
Fixation: RuBP is a CO2 acceptor, reaction is catalysed by rubisco.
reduction- gp is reduced to Triose phosphate, requires NADPH and ATP
Regeneration; Triose phosphate used to regenerate RuBP.
Factors affecting photosynthesis
Temperature, CO2 concentration, light intensity and wavelength. Something else becomes the limiting factor for photosynthesis
Concs of CO2 in the air at different heights above the ground in forest changes over a period of 24 hours. Explain why.
High conc of CO2 linked with darkness, no photosynthesis in the dark/ light dependent reaction, in dark plants respire, in light the rate of photosynthesis is greater than the rate of aerobic respiration. decrease in CO2 with height. At ground level there are fewer leaves.
Commercial glasshouses
Enhance temperature, carbon dioxide concentration and light intensity. Manipulation of these factors increase productivity and produced high yields.
Nucleus
Structure- nuclear envelope- double membrane and pores. chromosomes, nucleolus
Function- site of DNA replication, production of mRNA, tRNA and rRNA. Stores genetic information for polypeptide production.
Mitochondria
Double membrane, inner membrane highly folded to form cristae, matrix containing mitochondrial DNA, ribosomes, proteins and lipids
Function- site of ATP production by aerobic respiration
RER
Structure- highly folded membrane with 80s ribosomes, membrane folds to form flattened sacks called cisternae, joined to nucleus
Function- synthesis and transport of proteins throughout the cell
SER
Structure- highly folded membrane forming cisternae
Function- recombines gylcerol and fatty acids to make triglycerides- site of lipid synthesis
Cytoplasmic ribosome
Made up o 2 sub-units that are made of long strands of rRNA and ribosomal proteins
Contains 80s cytoplasmic ribosomes in eukaryotes
Function- sight of protein synthesis from amino acids
Golgi
structure- flattened sacs of membrane filled with fluid, Golgi vesicles pinch off from the main membrane
Function- sorts, modifies and packages proteins into vesicles, may be used to form ribosomes.
Lysosomes
Structure- membrane bound organelle that stores and releases many hydrolytic enzymes
Function- contains hydrolytic enzymes
CSM
Made up of phospholipids
Function- controls what enters and leaves the cell
Centrioles
Structure- microtubules
Function- form a network of spindle fibres onto which chromosomes attach
Granum
Stacks of thylakoid membrane
Thylakoid membrane
Contains chlorophyll for photosynthesis and ATP synthase enzyme to produce ATP
Stroma
Fluid filled part, some of the photosynthesis reactions occur here
Starch grains
Energy storing molecule
Prokaryote
mesosome- highly folded section of the membrane. Plasmid, cell wall, cell membrane, capsule, flagellum.
Centrifugation
Ice cold- reduce the action of enzymes that would digest or h=gazelles
Isotonic- prevent osmosis of water in and out of organelles, so organelles don’t burst.
Buffered- stop ph changes which could denature.
Population
All the individuals of a given species living together in the same area at the same time
carrying capacity
carrying capacity is the maximum, equilibrium number of organisms of a particular species that can be supported in a stable environment. birth rates and death rates are in equilibrium.
ecosystem
a community made up of living organisms and their interactions with non-living components such as water and mineral soil
why do two species not have exactly the same niche?
different roles within the ecosystem . they would outcompete and one would be more successful.
what happens when niches overlap
species have adaptations that outcompete
method of quadrating
map the area using two tape measures. use a random number generator, place a quadrat at each intersection. can only measure stationary and slow moving populations
why is it incorrect to say that organisms live in the same niche
different organisms may operate the same ecological niche whilst competing until one is eliminated.
how to know when to stop quadrating
calculate running mean, stop sampling when there is little change, enough to carry out a statistical test, a large number to make sure it is reliable, need to make sure it can be completed in the time available.
what rules are there for calculating an estimated population
not biased and random
all data is reliable and representable
quadrating
density- actual account of all individuals present- limitations- often time consuming, difficult to count
most accurate
percentage cover- the area of the quadrat covered by one species is recorded as a percentage of the total area. used when there are too many individuals to count. overlaying species may occur, total percentage may be over 100%
frequency- proportion of quadrat that contains a particular species. least accurate
factors affecting distribution
Biotic- competition, invasive species, human impact, algae
abiotic- climatic factors, physical factors such as soil and ater PH, aspect (NESW), turbidity and salinity of water.
systemic sampling
transect- recording what species are touching the line at each sampling point
belt transect- placing two parallel lines across, a meter apart and recording what species are found between the two lines
interrupted belt transects- using one line and placing a quadrat down at equally spaced sampling points and recording abundance in each quadrat.
sere
complete succession from pioneer community to climax community- has its own distinctive community of organisms.
mark release recapture
animals are ethically collected, animals are then marked, animals are released and left to redistribute into their population, recapture.
calculation: Number caught the first time x caught the second time/ number caught the second time that were previously marked.
pioneer species
the organisms that first colonise an area
climax community
final stage in an ecological succession- most stable, formed depending on abiotic factors
diversity
the relationship between the number of individual organisms and the number of species within a community.
stages of succession
colonization by named pioneer species, change in environment, enables other named species to colonise, change in diversity, stability increases, climac community represented by named species.
secondary succession occurs after forest fire or clearance of agricultural land.
deflected succession- when climac community is prevented from being established. community maintained under such conditions is known as a plagioclimax.
