Advanced Higher Biology - Quizlet import

how should sampling be carried out

in a manner which minimises the impact on wild species and habitats

techniques for sampling

point count, quadrats and transects (plants or slow moving organisms), capture techniques( nets and traps) for mobile species, camera traps and scat sampling (elusive species)

Hazards in fieldwork

Hazards in fieldwork include:

• Adverse weather conditions

• Difficult terrain

• Problems associated with isolation

• Contact with harmful organisms

Control measures in field work

Control measures include appropriate:

• Equipment

• Clothing

• Footwear

• Means of communication.

How can identification of an organism in a sample be made?

classification guides, biological keys or analysis of DNA or protein

how can organisms be classified

taxonomy and phylogenetics

taxonomy

the identification and naming of organisms and their classification into groups based on shared characteristics. classic classification is based on morphology.

Phylogenetics

the study of evolutionary history and relationships among individuals or groups of organisms. it is changing the traditional classification of many organisms.

divergent evolution

when two or more species sharing a common ancestor become more different over time

convergent evolution

Process by which unrelated organisms independently evolve similarities when adapting to similar environments

how does phylogenetic work?

using heritable traits such as morphology, DNA sequences, and protein structure to make inferences about an organisms evolutionary history and create a phylogenetic tree

phylogenetic tree (phylogeny)

a diagrammatic hypothesis of its relationships to other organisms

taxonomic groups

Nematodes, arthropods and chordates

example of nematode model organism

c.elegans

example of arthropod model organism

drosophila melanogaster ( fruit fly )

example of chordates model organism

mice, rats, zebrafish

what gives information on environmental qualities such as pollution

presence, absence or abundance of indicator species

mark and recapture formula

N=MC/R

mark and recapture formula key

a sample of population is captured and marked (M) and released. after an interval of tie a second sample is captured (C). If some of the individuals are recaptured (R) then the total population (N) can be calculated

what does mark and recapture assume

all individuals have an equal chance of capture, that there is no immigration or emigration, and that individuals that are marked and released can mix fully and randomly with the total population.

methods of marking

Banding, tagging, surgical implantation, painting and hair clipping

measurements used to quantify animal behaviour

latency, frequency and duration

latency

the time between the stimulus occurring and respond behaviour

frequency

the number of times a behaviour occurs within observation period

duration

length of time each behaviour occurs during observation period

ethogram

lists species specific behaviours to be observed and recorded in the study.

anthropomorphism

the attribution of human traits, emotions or intentions to non - human entities. can lead to invalid conclusions

how to calculate time budget with ethogram

record duration of each of the behaviours in the ethogram, together with the total time of observation

evolution

is the change over time in the proportion of individuals in a population differing in one or more inherited traits.

during evolution changes in allele frequency occur through..

non random process of natural selection and sexual selection and random process of genetic drift

variation is the result of…

mutation

what is the original source of new sequences of DNA

mutation

what is selection pressures a result of

populations producing more offspring than the environment can support

result of individuals having variation that is better suited to environment

survive longer and produce more offspring which is passing on those alleles to next generation giving advantage

selection results in…

the non-random increase in the frequency of advantageous alleles and the non-random decrease in the frequency of deleterious alleles

sexual selection

the non random process involving the selection of alleles that increase the individuals chances of mating and producing offspring

sexual dimorphism

where two sexes of the same species exhibit different characteristics

sexual selection may lead to..

sexual dimorphism

sexual selection can be due to

female choice and male-male rivalry

female choice

involves females assessing the fitness of males. this may result in males attempting to 'attract' females through elaborate displays ( feathers, puffed chest)

male-male rivalry

large size or weaponry increases access to females through conflict ( antlers to compete for females)

how does genetic drift occur

when chance events cause unpredictable fluctuations in allele frequency's from one generation to the next

when does genetic drift have a larger impact

in smaller populations as alleles more likely to be lost from the gene pool.

genetics drift can occur because of..

bottleneck effect and founder effect

founder effect

occur through the isolation of a population from a larger population. the gene pool of the new population is not representative of that in the original gene pool.

bottleneck effect

occurs when a population size is reduced for at least one generation. the reduced population can have lower genetic diversity.

effect of genetic drift on new gene pool

it is altered because certain alleles may be under represented or over represented and allele frequencies change. ( new gene pool not representative or original one)

strong selection pressures =

rapid rate of evolution

selection pressures are

environmental factors that influence which individuals pass on their alleles

biotic selection pressures

competition, predation, disease, parasitism

abiotic selection pressures

changes in temperature, light, humidity, pH, salinity

hardy- Weinberg (HW) principle

in the absence of evolutionary influences, allele and genotype frequencies in a population will remain constant over the generations

conditions for maintaining the HW equilibrium

no natural selection, random mating, no mutation, large populations size, no gene flow through migration in or out

use of HW principle

determine whether a change in allele frequency is occurring in a population over time. changes suggests evolution is occurring

HW formula

p^2 + 2pq + q^2 = 1

HW key

p= frequency of dominant alleles (A)

q= frequency of recessive alleles (a)

p2=frequency of homozygous dominant genotype (AA)

2pq= frequency of heterozygous genotype (Aa)

q2= frequency of homozygous recessive genotype (aa)

fitness

an indication of an individuals ability to be successful at surviving and reproducing. it refers to the contribution made to the gene pool of the next generation by individual genotype

fitness can be defined in terms of

absolue or relative

absolute fitness

The ratio between the number of individuals of a particular genotype after selection, to those before selection ( after/before)

absolute fitness stable genotype

answer = 1.0

absolute fitness increase genotype

bigger than 1.0

absolute fitness decreased genotype

smaller than 1.0

relative fitness

the ratio of the number of surviving offspring per individual or a particular genotype to the umber of surfing offspring per individual of the most successful genotype

co evolution

the process by which two or more species evolve in response to selection pressures imposed by each other. a change in the traits of one species acts as a selection pressure on the other species seen with species that have symbiotic relationships

symbiosis

co evolved intimate relationships between members of two different species ( impact can be positive, negative or neutral)

types of symbiotic interactions

mutualism, commensalism and parasitism

mutualism

both organism are interdependent on each other for resources or other services, (+/+)

Commensalism

only one organism benefits (+/0)

parasitism

the parasite benefits in terms of energy or nutrients and the host is harmed in terms of loss of these resources (+/-)

the red queen hypothesis

in a co-evolutionary relationship, change in the traits of one species can act as a selection pressure on the other species, meaning that species in these relationships must adapt to avoid extinction.

sexual reproduction

the production of new living organisms by combining genetic information from two different individuals of different types (sexes)

costs of sexual reproduction

males being unable to produce offspring, only half of each parents genome passed onto offspring disrupting successful parent genomes

benefits sexual reproduction

genetic variation (benefits out weigh costs)

what does genetic variation provide

The raw material required for adaptation, giving sexually reproducing organisms a better chance of survival under changing selection pressures

red Queen hypothesis in terms of sexual reproduction

parasite pressure maintains sexual reproduction in the host population by selecting for the ability to produce rare genotypes that are resistant to infection

in co evolutionary relationships ( parasite and host) why are sexually producing hosts selected for

better able to resist and tolerate parasitism will have greater fitness,

benefit of host reproducing sexually

the genetic variability in their offspring reduces the chances that they will be susceptible to infection by parasites

asexual reproduction

a type of reproduction by which offspring arise from a single organism and inherit the genes of that parent only it does not involve the fusion of gametes

advantages asexual reproduction

entire genome passes on to offspring ( advantage in very narrow stable niches or when re-colonising disturbed habitats ) one parent can produce daughter cells and establish colony of unlimited size over time. offspring produced more often and in larger numbers

examples of asexual reproduction in eukaryotes

vegetative cloning in plants and parthenogenesis in lower plants and animals that lack fertilisation

parthenogenesis

reproduction from a female gamete without fertilisation. (more common in cooler climates which are disadvantageous to parasites or regions of low parasite density or diversity )

costs of asexual reproduction

not able to adapt easily to changes in environment, but mutations can occur that provide some degree of variation and enable some natural selection and evolution to occur

mechanisms that organisms that only use asexual reproduction have to increase variation

horizontal gene transfer

meiosis

the division of the nucleus that results in the formation of haploid gametes from a diploid gametocyte

homologous chromosomes

Chromosomes that have the same size, same centromere position and with the same sequence of genes at the same loci.

meiosis I

the chromosomes have replicated prior to meiosis 1, each consist of two genetically identical chromatids attached at the centromere, chromosomes condense and pair up. chiasmata form at points of contact between non sister chromatids of a homologous pair and sections of DNA are exchanged. (linked genes are those on the same chromosome crossing over can result in new combinations of alleles of these genes. ) the crossing over of DNA is random and produces genetically different recombinant chromosomes. spindle fibres attach to the homologous pairs and line them up at the equator of the spindle. the orientation of the pairs of homologous chromosomes at the equator is random. each pair of homologous chromosomes is positions independently of the pairs irrespective of their maternal and paternal origin. this is know as independent assortment . the chromosomes of each homologous pair are operated and move towards opposite pole. cytokinesis occurs and two daughter cells form .

meiosis II

each of the two cells produced in meiosis I undergo a further division which the sister chromatids of each chromosome are separated. a total of four haploid cells are produced.

chiasmata

the part of attachment of non sister chromatids of homologous chromosomes where crossing over takes place.