Unit 3 Topic 1
Identify the survey technique show in the image provided.
quadrat
Identify which species are most likely to be involved in competitive exclusion.
a) Similar species occupying the same niche
b) Similar species occupying different niches
c) Similar species occupying the same habitat
d) Similar species occupying different habitats
a) Similar species occupying the same niche
Which of the following best describes transcription?
B – The process of copying DNA into an mRNA strand
What is the main purpose of PCR?
To make many copies of a specific DNA sequence
In a population of beetles, most individuals are green, which helps them blend into leafy environments. A mutation produces brown beetles, which are more visible to predators. Over several generations, the proportion of brown beetles increases as the environment gets drier. This change is best described as:
A. Genetic drift resulting from random mating
B. Microevolution through natural selection acting on phenotypic variation
C. Macroevolution due to speciation
D. Artificial selection guided by human influence
B Microevolution through natural selection acting on phenotypic variation
Which of the following best describes species richness?
A. The number of individuals in a population
B. The number of different species in a given area
C. The relative abundance of species in a community
D. The genetic variation within a species
B. The number of different species in a given area
Why is only about 10% of energy passed on from one trophic level to the next in a food chain?
Only about 10% of energy is passed on because most energy is used by the organism for respiration, movement, and maintaining body functions, or is lost as heat and waste.
Only a small amount is stored in biomass for the next trophic level.
Explain the role of DNA polymerase in DNA replication.
synthesises new DNA strands
by adding complementary nucleotides to a growing chain
in the 5' to 3' direction
Which of the following best explains how epigenetic factors control gene expression?
A. They change the order of DNA bases.
B. They add or remove chemical tags that switch genes on or off.
C. They break down mRNA before translation.
D. They change amino acids directly in the protein.
B. They add or remove chemical tags that switch genes on or off.
Define the term microevolution.
Small-scale variation of allele frequencies within a species or population, in which the descendant is of the same taxonomic group as the ancestor
Classify the ecosystem according to the Holdridge life zone system (diagram provided).
Biotemperature -> 5oC
Annual precipitation -> 600mm
Latitudinal regions -> Boreal
Wet forest
What process occurs in plants to convert nitrates into nitrogen which is released back into the atmosphere?
denitrification
Explain the difference between the roles of mRNA and tRNA in protein synthesis.
mRNA carries the genetic code copied from DNA in the nucleus to the ribosome.
tRNA transports specific amino acids to the ribosome and matches its anticodon with the complementary codon on the mRNA, ensuring the correct amino acid sequence in the polypeptide.
What is the difference between DNA sequencing and DNA profiling?
DNA sequencing determines the order of the bases in a DNA fragment.
DNA profiling compares patterns in specific regions of DNA to distinguish between individuals without reading the full sequence.
Which of the following is an example of convergent evolution?
A. Different finch species on the Galápagos Islands evolving from a common ancestor
B. The similar body shapes of dolphins and sharks despite different evolutionary origins
C. The rapid diversification of mammals after the extinction of the dinosaurs
D. The gradual change in horse species from small forest dwellers to large grassland grazers
B. The similar body shapes of dolphins and sharks despite different evolutionary origins
Which group (on the cladogram provided) diverged earliest from the common ancestor of primates?
c. Lemurs
In 2020, the ibis population at South Brisbane was 2000. In 2021, 100 ibises were born, 50 died, 200 immigrated, and 120 emigrated. In 2021, what was the ibis population's growth rate (%)?
change = 130
130/2000 x 100 = 6.5%
What happens to the protein if bases are added or removed from DNA?
A frameshift mutation shifts the reading frame of the codons, which usually changes all amino acids after the mutation.
This often produces a non-functional protein.
In pea plants, purple flowers (F) are dominant over white flowers (f). If a heterozygous plant is crossed with a homozygous recessive plant, what is the expected phenotypic ratio of the offspring?
parents: Ff x ff
offspring in Punnett square; Ff, Ff, ff, ff
50% purple (Ff) : 50% white (ff)
Explain how isolation leads to new species.
Isolation stops populations from breeding with each other which prevents gene flow.
Over time, they change through natural selection and mutations.
Eventually, they become so different (changes to allele frequencies) they can’t interbreed anymore, therefore making new species.
The figure provided shows a forest before harvesting (pre-harvest) and after harvesting (post-harvest).
Identify an appropriate ecological surveying technique and sampling method that could be used to effectively analyse the change in species diversity between the two ecosystems.
survey technique: line or belt transect
survey method: systematic sampling
The carbon cycle moves carbon between the atmosphere, plants, animals, and decomposers.
a) State how plants take in carbon.
b) State how animals get carbon.
c) Explain the role of decomposers in the carbon cycle.
d) Give one human activity that increases carbon in the atmosphere.
Plants take in carbon by absorbing carbon dioxide (CO₂) from the atmosphere during photosynthesis.
Animals get carbon by eating plants or other animals that contain carbon compounds.
Decomposers break down dead organisms and waste, releasing carbon back into the atmosphere as CO₂ through respiration and recycling nutrients into the soil.
Burning fossil fuels (other possible answers: deforestation, industrial processes).
During meiosis how does crossing over in Prophase I contribute to genetic variation?
By exchanging segments of DNA between non-sister chromatids of homologous chromosomes, creating new combinations of alleles on the chromosomes.
What would the phenotypic ratio be in the offspring if two individuals with blood type AB were crossed?
Parents: IAIB x IAIB
Offspring (in punnett square): IAIA, IAIB, IAIB,
IBIB
ratio of blood types:25%A, 50% AB, 25% B
Discuss the role of mass extinction events in shaping patterns of evolution.