Unit2 - Organisms and Evolution Flashcards
What is a hazard ( in the field) ?
Something with the potential to cause harm i.e manual handling and moving vehicle
What is a risk?
The likelihood of harm arising from exposure to a hazard.
What are some examples of hazards when working in the field?
Terrain- Assessing terrain prior to setting out is essential. Variations may include uneven surfaces, flat areas, hills, and steep gradients.
Adverse weather conditions- Can change very quickly in the field. Appropriate clothing, footwear, and supplies should be selected. In extreme weather, fieldwork may have to be postponed or abandoned.
Isolation- Areas of fieldwork can often be isolated.
Make sure someone at base is aware of routes and expected time of return.
Contact with harmful organisms- dangerous, poisonous or venomous can pose harm to humans.
What do risk assessments involve?
Risk assessment involves identifying control measures to minimise risk.
They should be carried out prior to any fieldwork.
Name some control measures while completing the fieldwork.
Control measures while completing fieldwork can include: Appropriate equipment Appropriate clothing Footwear Means of communication.
Sampling should be carried out in a way that minimises the impact on what?
wild species and habitats.
Consideration should be given to what types of species and habitats?
Consideration should be given to rare and vulnerable species and habitats that are protected by legislation.
What species can you sample using…. Point count?
Birds.
What species can you sample using…. Transect?
Plants / Sessile/ slow moving organisms.
What species can you sample using…. remote detection?
elusive species
What species can you sample using…. capture techniques?
mobile species
Describe the capture technique- point count.
A point count involves the observer recording all individuals seen from a fixed point count location.
This can be compared to other point count locations or with data from the same location gathered at other times.
This method is often used to count bird populations in a given area, over a set period of time.
Describe the capture technique- transects using quadrats.
A transect is a line along which different samples can be taken. These are often set up along an area where the terrain or abiotic factors are variable.
Quadrats of a suitable size and shape for the area are placed along the transect, allowing sessile or slow-moving organism abundance to be recorded.
Abiotic factors can also be measured to determine the habitat features for the organisms.
Describe the capture technique- capture techniques
Capture techniques such as traps and nets, are used for mobile species.
Describe the capture technique-remote detection
Remote detection is used to detect elusive (those that are difficult to find) species. They can be sampled directly by using camera traps or indirectly using scat sampling (examining faecal matter).
Identification of an organism in a sample can be made using what?
Classification Guides
Biological keys
Analysis of DNA or protein.
Organisms can be classified by what?
taxonomy and phylogenetics
What is taxonomy?
Taxonomy involves the identification and naming of organisms and their classification into groups based on shared characteristics. Classic taxonomy classification is based on morphology (the structures and features of organisms).
What is phylogenetics?
Phylogenetics is the study of the evolutionary history and relationships among individuals or groups of organisms. Phylogenetics is changing the traditional classification of many organisms.
What does Phylogenetics use?
Phylogenetics uses heritable traits such as morphology, DNA sequences, and protein structure to make inferences about an organism’s evolutionary history and create phylogeny (phylogenetic tree).
What is a phylogenetic tree?
Phylogenetic tree – a diagrammatic hypothesis of its relationship to other organisms.
Genetic evidence reveals relatedness obscured by what types of evolution
divergent or convergent evolution.
What is divergent evolution?
Increase in morphological differences between species as each adapts to different ecological niches.
What is convergent evolution?
Decrease in morphological differences between species as they adapt to similar ecological niche.
Familiarity with taxonomic groupings allows what it be made?
Predictions and inferences to be made
between an organism and better-known (model) organisms.
What are nematodes?
Nematodes – the round worms which show great variety, many of which are parasitic e.g. tapeworms.
What are arthropods?
Arthropods – the joint-legged invertebrates which are identified by their segmented body, typically with paired appendages, e.g. wasps, butterflies, spiders and crabs.
What are chordates?
Chordates – the sea squirts and vertebrates, e.g. birds, mammals, reptiles, amphibians and fish.
What are model organisms?
Model organisms are those that are either easily studied or have been well studied.
Model organisms from all taxonomic groups are used to obtain information that can be applied what?
Model organisms from all taxonomic groups are used to obtain information that can be applied to species that are more difficult to study directly.
Name a model organism.
Model organisms that have been important in the advancement of modern biology include:
The bacterium E. coli;
The flowering plant Arabidoposis thaliana;
The nemotode C. elegans;
The arthropod Drosophila melanogaster (fruit fly);
Chordates including mice, rats and zebrafish.
Why monitor populations?
Monitoring populations is essential in understanding environmental conditions.
Monitoring can allow us to identify areas of pollution vs clean.
What are indicator species?
The presence, absence or abundance of indicator species can give information of environmental qualities.
For example, the presence of pollutants.
Lichen can give information about air quality (sulphur dioxide levels).
Absence or reduced population indicates a species is what to some factor in the environment?
Susceptible
Abundance or increased population indicates it is what by the conditions?
favoured
Susceptible and favoured species can be used to monitor what?
an ecosystem.
Mark and recapture is a method used for what?
estimating population size.
How do you estimate the population size in calculation?
N = (MC)/R
A sample of the population is captured and marked (M) and released.
After an interval of time, a second sample is captured (C).
If some of the second sample are recaptured (R) then the total population can be represented by
What does mark and recapture technique assume?
This method assumes:
that all individuals have an equal chance of capture;
there is no immigration or emigration during the sample time;
there is no birth and death during the sample time;
That individuals that are marked and released can mix fully and randomly with the total population.
Name the 5 methods of marking?
Banding Tagging Surgical implantation Painting Hair clipping
The method of marking and subsequent observations must minimise the impact on the study species. It should not interfere with what?
It should not interfere with the individual’s normal behaviour or make it more conspicuous to predators.
The mark and recapture method must be clear in order to do what?
to permit subsequent observations.
What is ethology?
the study of animal behaviour.
What is Latency?
the time between the stimulus occurring and the response behaviour.
What is the frequency? (Animal behaviour)
The number of times the behaviour occurs within a period of observation.
What is the duration? (Animal behaviour)
The length of time each behaviour occurs during the observation period
Ethograms are methods of what?
recording animal behaviour over a set period of time.
What do ethograms list?
Specific behaviours observed and recorded in the study e.g eating lying down tail wagging.
The duration of each of the behaviours in the ethograms and what is recorded?
Total time of observation
A time budget can be constructed from an ethogram. What is a time budget?
shows the percentage of time spent on each animal behaviour.
What can a time budget be represented as?
pie chart, tables or charts
When performing an ethogram, what is it important to avoid doing what?
anthropomorphism
What is anthropomorphism?
assigning human emotions/ qualities to animal behaviour
What does anthropomorphism lead to?
invalid conclusion
What is a mutation?
Mutations are rare, random changes to genetic sequences which can be harmful, beneficial or neutral
What 2 ways can genetic material to be passed?
Vertically/ horizontally
What is evolution?
Evolution is the change over time in the proportion of individuals in a population differing in one or more inherited trait.
What is the allele frequency
Allele frequency = a measure of how common the allele is within a population/ the proportion of a given allele in the population with respect to all alleles of that gene.
During evolution changes in allele frequency can take place through the processes of:
Selection (non-random)
Sexual selection
Natural selection
Genetic drift (random)
Natural selection acts on what in populations.
genetic variation
Variation in traits arises as a result of what?
mutation.
Mutation is the original source of what?
new sequences of DNA.
These new DNA sequences that come about due to Mutation can be ……. alleles.
novel
Most mutations are harmful or neutral, but in rare cases they may be what?
beneficial to the fitness of an individual.
Describe the process of Natural selection.
As organisms produce more offspring than the environment can support, only the best adapted will survive.
Individuals with variations of a trait which make them better suited to their environment tend to survive longer and produce more offspring
When they breed, they pass on those alleles that confer an advantage to the next generation.
Therefore, natural selection results in the ….(1)…… in the frequency of advantageous alleles and the ….(2)……. in the frequency of deleterious alleles.
(1) - NON RANDOM INCREASE
(2) - NON RANDOM DECREASE
What is sexual selection?
Sexual selection is the non-random process involving the selection of alleles that increase the individual’s chances of mating and producing offspring.
Sexual selection does not increase the chances of survival, just what?
the likelihood that the organism will reproduce and pass on its alleles.
What does sexual selection sometimes lead to?
sexual dimorphism-the presence in a population of two sexes each with a different PHENOTYPE (look different)
Sexual selection can be due to what 2 things?
Female choice/ male vs male rivalry
Describe Male vs Male rivalry (sexual selection)
Males compete aggressively to defend territories and get access to females.
Larger, stronger males or males with better weaponry increase access to females through conflict.
Describe female choice(sexual selection)
If males cannot control access to females then females will choose a male based on traits he displays that are considered to be “high quality” or fitness.
e.g. ornaments or bright colouring
Genetic drift is a random process which results in what?
an increase or decrease in the frequency of inherited traits.
Genetic drift occurs when?
chance events (e.g. natural disaster) cause unpredictable fluctuations in allele frequency from one generation to the next.
Genetic drift is more important in what type of populations due to what?
small populations, as alleles are more likely to be lost from the gene pool.
what are two examples of genetic drift?
founder effect
population bottleneck
When do population bottlenecks occur?
population bottlenecks occur when a population size is reduced for at least one generation.
how does the founder effect occur?
Founder effects occur through the isolation of a few members of a population from a larger population. The gene pool of the new population is not representative of that in the original gene pool.
Why is a gene pool altered by genetic drift?
A gene pool is altered by genetic drift because certain alleles may be under-represented or over-represented and allele frequencies change.
When what are strong, the rate of evolution can be rapid.
selection pressures
What are selection pressures?
Selection pressures are the environmental factors that influence which individuals in a population pass on their alleles.
What are some biotic selection pressures?
competition, predation, disease, parasitism
What are some abiotic selection pressures?
changes in temperature, light, humidity, pH, salinity.
The Hardy-Weinberg (HW) principle states what?
That, in the absence of evolutionary influences, allele and genotype frequencies in a population will remain constant over the generations.
The HW principle can be used to determine what?
whether a change in allele frequency is occurring in a population over time.
The HW principle can be used to calculate what?
allele, genotype, and phenotype frequencies in populations
Describe the Hardy-weinberg equation?
p2 + 2pq + q2 = 1
p+q=1
p = frequency of dominant allele
q = frequency of recessive allele
p2 = frequency of homozygous dominant genotype
2pq = frequency of heterozygous genotype
q2 = frequency of homozygous recessive genotype
Changes suggest evolution is occurring.
what are the conditions for maintaining HW equilibrium
no natural selection,
random mating occurs,
no mutation,
large population size and
no gene flow (through migration, in or out).
‘Fitness’ of the individual is an indication of what?
Fitness is an indication of an individuals ability to be successful both at surviving and reproducing.
Fitness is a measure of the tendency of some organisms to do what?
produce more surviving offspring than competing members of the same species.
Fitness refers to what?
the contribution that is made to the gene pool of the next generation by individual genotypes.
Fitness can be determined in what terms?
absolute and relative terms
What is absolute fitness?
Absolute fitness is the ratio between the number of individuals of a particular genotype after selection, to those before selection.
Frequency of a particular genotype after selection/ Frequency of a particular genotype before selection
What happens if you get an absolute fitness of:
a) 1
b) above 1
c) below 1
If the absolute fitness is 1, then the frequency of that genotype is stable.
A value greater than 1 conveys an increase in the genotype
A value less than 1 conveys a decrease.
What is relative fitness?
Relative fitness is the ratio of the number of surviving offspring per individual of a particular genotype to the number of surviving offspring per individual of the most successful genotype.
Number of surviving offspring per individual of a particular genotype
/ Number of surviving offspring per individual of the most successful genotype
What is co-evolution
Co-evolution is the process by which two or more species evolve in response to selection pressures imposed by each other.
In co-evolution, a change in the trait of one species acts as what on the other species
selection pressure
Co-evolution is frequently seen in pairs of species that have what?
symbiotic interactions.
What is symbiosis?
Symbiosis – co-evolved intimate relationship between members of two different species.
What is mutualism?
Mutualism: both organisms in the interaction are interdependent on each other for resources or other services. As both organisms gain from the relationship, the interaction is (+/+).- plover and crocodile
What is parasitism?
Parasitism: the parasite benefits in terms of energy or nutrients and the host is harmed as the result of the loss of these resources (+/-)- vampire finch/ bobby
What is communalism?
Commensalism: only one of the organisms benefits (+/0)- fox and carbiou.
What does the red queen hypothesis state?
The Red Queen hypothesis states that, in a co-evolutionary relationship, change in the traits of one species can act as a selection pressure on the other species.
This means that species in these relationships must adapt to avoid extinction.
What is sexual reproduction?
Sexual- offspring arise from the combination of male and female gametes after the process of fertilisation.
What is asexual reproduction?
Asexual- offspring arise from a single organism and share the DNA of that parent only. Offspring can be classed as clones.
What are the costs (disadvantages) of sexual reproduction?
There are two main disadvantages:
In any population where sexual reproduction is the reproductive strategy, only half of the population are able to produce offspring.
Sexual reproduction involves the mixing of genetic information. This means only half of each parent’s genome passed onto offspring, disrupting successful parental genomes
What are the benefits (advantages) of sexual reproduction?
Although there are costs to sexual reproduction, the benefits outweigh these due to an increase in genetic variation in the population.
This provides the raw material for adaptation which gives sexually reproducing organisms a better chance of survival under changing selection pressures (e.g. surviving new strains of diseases)
Without such genetic variety produced by sexually reproducing organism what would stop?
the Red Queen’s arms race
Co-evolutionary interactions between parasites and hosts may select for what type of hosts?
sexually reproducing hosts.
What does the genetic variability of sexually reproducing organism’s offspring do to their chances when they meet a parasite?
in their offspring decreases the chances that all of the individuals will be susceptible to infection by parasites.
The genetic variability in their offspring decreases the chances that all of the individuals will be susceptible to infection by parasites. What does this mean for the host?
This means that the host will be able to resist and tolerate parasitism, therefore showing greater fitness.
When will a parasite have greater fitness?
Parasites that are better able to feed, reproduce and find new hosts have greater fitness.
What are the benefits of asexual reproduction?
Just one parent can produce daughter cells and establish a colony of virtually unlimited size over time.
Offspring can be reproduced more often and in larger numbers
Whole genomes are passed on from parent to offspring.
When is asexual reproduction a useful strategy to use?
Maintaining the genome of the parent is an advantage particularly in very narrow, stable niches (very little environmental changes) or when re-colonising disturbed habitats.
What are examples of asexual reproduction in Eukaryotes?
Budding
vegetative cloning in plants
parthenogenesis in lower plants and animals that lack fertilisation.
What is parthenogenesis?
Parthenogenesis is a type of asexual reproduction in which an unfertilised female gamete develops into a new individual
What type of organisms carry out parthenogenesis?
Fire ants
Stick insects
Komodo dragon
