Biology (& look at P2 deck) Flashcards
(38 cards)
define stable community
a community where all species & environmental factors are in balance – so the population sizes remain quite constant
how do abiotic & biotic factors impact a species?
impact distribution & abundance (population size) of a species = change the community.
if # of population falls too much, they are unable to breed & may be lost from community
what happens at early & late stages of succession?
early: hostile environment = poor soil quality & high wind intensity = organisms must be highly adapted to cope with abiotic factors
late: stable community with less hostile environment, but more biodiversity = organisms must be adapted for biotic factors to compete
what is biomass?
mass of living material in an organism - dry mass
why repeat experiment?
to make results more reliable by calculating a mean & to be representative of the area & to identify anomalies
what processes recycle materials?
photosynthesis
respiration
combustion
why are decomposers important?
1- return carbon to atmosphere as CO2 through respiration = for photosynthesis
2- return mineral ions to soil for plants to use = magnesium & nitrate
describe the carbon cycle
1- ps by plants/algae removes CO2 from atmosphere
2- carbon is used to make carbohydrates, lipids & proteins = organic compounds
3- respiration by all organisms releases CO2 into atmosphere
4- carbon is passed from plants to animals by feeding & ingestion
5- when plants or animals die, microorganism decomposers break down (digest) their bodies using enzymes
6- combustion of fossil fuels releases CO2 into atmosphere
describe the water cycle
1- evaporation of water from earth falls as precipitation
2- absorption of water by plants via osmosis into roots
3- transpiration by plants releases H2O into atmosphere
4- production of urine, sweat & faeces by animals
5- respiration by all organisms produces H2O
what do decomposers do?
break down dead plant & animal matter by secreting enzymes into environment, which break down large molecules in dead organisms into small & soluble food molecules that diffuse into the microorganism –> used to make larger molecules or in respiration
how does a biogas generator work?
anaerobic respiration by bacteria produces methane gas – biogas generators used to produce methane gas for renewable fuel
what are the environmental changes?
1- temperature
2- availability of H2O
3- composition of atmospheric gases e.g. O2, CO2, CH4 –> greenhouse gases –> global warming
what categories can environmental changes be?
seasonal (migration)
geographical (where species can survive)
caused by human interaction
what is the importance for medicine of understanding the human genome?
search for genes linked to different types of diseases
understand & treat inherited disorders e.g. cystic fibrosis & polydactyly
to trace human migration patterns of the past
what is the extensive variation in a population due to?
mutations
define evolution
the change in inherited characteristics of a population over time through natural selection, which can form new species
describe the 3 domains
archaea - primitive bacteria
bacteria - true bacteria
eukarya - animals, plants, fungi & protists
what is therapeutic cloning & describe?
embryo is produced with same genes/DNA as patient
stem cells from the embryo are not rejected by the patient’s body so they may be used for medical treatment
what are the risks of using stem cells?
viral infection
ethical objections - embryo cannot consent
religious objections - there should be no interference with human reproduction
describe the relationship b/w health & disease
health = state of physical, mental, & social well-being
disease = disorder that affects an organism’s organs, tissues, or cells
disease can impact health, but lack of disease does not necessarily mean good health
how can pathogens be transmitted by water?
humans: contaminated water/food, causing e.g. cholera & salmonella
plants: fungal spores can be spread in water
describe the interaction of different types of diseases
defects in immune system –> an individual is more likely to suffer from infectious diseases
viruses can trigger cancer
reaction of the immune system to pathogens can trigger allergic reactions
severe physical ill health can lead to mental illness
name one use of mAbs
measure levels of hormones/chemicals in the blood
what are the physical, chemical & mechanical plant defenses?
physical:
cellulose cell wall
waxy cuticle
layers of dead cells around stems (bark on trees) which fall off
chemical:
poisons to deter herbivores
antibacterial chemicals
mechanical:
thorns/hairs to deter animals
leaves which droop or curl when touched
mimicry to trick animals
