M3 Flashcards
Define the terms ecosystem, community, population
Individuals of the same species living together in a particular locations make up a population. Different populations interact with each other to form a community. The interactions between the community and their physical environment is an ecosystem; thus an ecosystem is all of the abiotic and biotic factors in a particular area.
Define the term selection pressure
Selection pressures are the abiotic and biotic factors which affect an organism’s ability to survive in a particular environment
Negative selection pressures decrease the occurrence of a trait
Positive selection pressure increases the occurrence of a trait
Selection pressures act on organisms in an ecosystem.
List a range of abiotic/biotic factors, why is this important
Selection pressures can include abiotic factors such as temperature, light intensity, soil type, water availability and gas concentration in water and biotic factors such as competition between members of a species for the same limited resources, predators and availability of prey.
If a factor in the environment changes, then so may what constitutes a favourable trait, and because selection pressures determine which organisms are most likely to survive and hence pass on their traits (genes), selection pressures drive natural selection and evolution
Compare the structural, behavioral and physiological adaptations that have allowed cane toad populations to rise rapidly
Describe the selective pressures that cane toads impose on other organisms
Define the term adaptation (2)
Adaptations are the features that help organisms survive in a particular environment. Animals that are suited to their environment are more likely to survive and have offspring (so pass on their genes). Adaptations may be inherited, or arise spontaneously via mutation. Adaptations can be structural, physiological and behavioural.
Describe a range of structural adaptations of plants and animals, and explain how these increase the ability to survive in their environment
Needle-like leaves (small SA:V ratio) to reduce water loss
Woody fruits: these conserve water and are more resistant to fire
Leaves that hang down: this reduces sun exposure and thus water loss
Thick, waxy cuticles - Eucalypts and banksias
Sunken stomata
Leaves that roll: this internalises stomata and reduces water loss.
Describe a range of physiological adaptations of plants and animals, and explain how these increase the ability to survive in their environment
Many mammals that live in arid environments have large ears. This increases their ability to lose heat.
Many desert organisms are small, meaning that the organism can live in a burrow, rather than above ground (see below)
Animals that live in cold climates tend to have fur or blubber to help insulate them against the cold, such as the fairy penguin:
Animals’ teeth and internal organs differ depending on diet (herbivore, carnivore or omnivore).
Aquatic organisms have adaptations to help them move through the water, such as fins or webbed feet
Many birds have bright or elaborate feathers to impress mates, such as the birds of paradise of PNG (the below is a ribbon-tailed astrapia)
Animals will have different colours for camouflage, to indicate that they’re poisonous, or to mimic poisonous organisms.
Describe a range of behavioural adaptations of plants and animals, and explain how these increase the ability to survive in their environment
Define speciation
the formation of new and distinct species in the course of evolution.
Define genetic drift
random fluctuations in allele frequencies (both positive and negative), generally in smaller populations, caused by “sampling errors”- can lead to a succession of small genetic changes that, over time, lead to the two populations to eventually become so genetically different that they are no longer able to interbreed. When this happens, we say that speciation has occurred- the populations are now considered to be two distinct species (speciation).
Describe the effect of the different selection pressures of the islands of the Galapagos on the finches
Explain how Darwin’s finches support the Theory of Evolution by Natural selection
Explain how Darwin’s observations in Australia support the Theory of Evolution by Natural selection
VISTA: Variation, Inheritance, Selection, Time and Adaptation
List the steps of natural selection
VBVEIS
Variation, Biodiversity, Variability, evolution, isolation, speciation
Define the term survival of the fittest
Identify that natural selection is driven by mutation
Describe the different theories of the origin of life on Earth (3)
Identify the order in which major classes of organisms appeared/events appeared, such as:
prokaryotes
eukaryotes
jawless fish
reptiles
non-vascular plants
terrestrial organisms
dinosaurs
mammals
angiosperms
Explain the development of biological diversity on Earth in terms of Evolution
Compare and contrast gradualism with punctuated equilibrium
Describe what is meant by convergent evolution, and give examples
Explain how evolution accounts for convergent evolution
Explain how evolution accounts for divergent evolution
Explain what is meant by divergent evolution, and give examples
Explain what is meant by coevolution, and give examples
Define microevolution and macroevolution, and give examples of each (where we’re up to in class)
Define the terms mutation, codon, highly conserved
Explain how molecular clocks are evidence for evolution, giving an example
Define the term homologous structures, and identify examples
Explain how homologous structures are evidence for evolution
Define the term analogous structures, and identify examples
Explain how analogous structures are evidence for evolution, giving an example
Define the term vestigial structure, and identify examples
Explain how vestifial structures are evidence for evolution
Define the term biogeograpy
Define the term comparative anatomy, and explain how it gives evidence of evolution
Explain how isolation of organisms, e.g. the ratites, provides evidence for evolution
Explain how migration of organisms, e.g. the ancestor of the camel, provides evidence for evolution
Identify the different types of fossils
Describe the conditions necessary for fossilisation to occur
Compare and contrast absolute and relative dating
Define the Law of Superposition
List the characteristics of index fossils
Describe absolute dating techniques e.g. carbon dating
Explain how the fossil record provides evidence for evolution
Explain the importance of antibiotics to human health
Identify how antibiotic resistance arises in bacteria (mutation)
Identify how antibiotic resistance arises in bacteria (vertical gene transfer)
Identify how antibiotic resistance arises in bacteria (horizontal gene transfer)
Describe how human activity contributes to antibiotic resistance (farming)
Describe how human activity contributes to antibiotic resistance (misuse and overuse of antibiotics)
Explain the consequences of antibiotic resistance
Explain the development of antibiotic resistance in terms of the steps of natural selection
define gene flow
the exchange of genetic material between different populations of a species, often by migration of members of the populations
define bottleneck effect
The bottleneck effect occurs when an initially large population is suddenly reduced in numbers, such as by a natural disaster. The reduced size of the population increases inbreeding and reduces variation in the gene pool.
define founder effect
The founder effect occurs when a small group of individuals moves away from the larger population- inbreeding increases and allele frequencies decrease- their small gene pool will not very accurately represent the larger population from which they originated.
define ecological niche
In ecology, the term “niche” describes the role an organism plays in a community. A species’ niche encompasses both the physical and environmental conditions it requires (like temperature or terrain) and the interactions it has with other species (like predation or competition).
Example: The platypus and the European water vole: Darwin observed these organisms, and he realised that they occupied the same ecological niche: both are mammalian river dwellers, with similar diets, and adapted to be excellent divers and swimmers.
Variability (natural selection)
Evolution (Gradualism and punctuated equilibrium)
Evolution (macro vs micro)
Macroevolution is caused by the accumulation of microevolutionary changes that lead to speciation, and then, beyond the species level.
Macro evolution
Tenolophos and steropodon are two monotremes fromt eh cretaceous period that have become extinct, and are believed to be closely related to the modern platypus. The platypus’s ancestors are believed to have diverged from the mammaliaan lineage about 210 million years ago. When a platypus hatches, it has teetch that fall out wihtin the first couple of weeksd because they no longer have any use for them. This vestigial structure proves that the platypus has evolved into not needing teeth as modern platypi grind food between horny plates on their upper and lower jaws
Evolution (convergent vs divergent)
Convergent evolution is when two species with different ancestral origins develop similar characteristics, while divergent evolution refers to when two species diverge from a common ancestor and develop different characteristics.
allopatric speciation and isolation
This is speciation caused by geographic isolation- a geographical barrier of some kind prevents gene flow between populations and over time, genetic drift leads to speciation. Isolation can be caused by tectonic activity, such as continents breaking apart, mountains forming or bodies of water separating the populations. Darwin’s finches are another example of allopatric speciation- the migrating finches were separated geographically onto the different islands of the Galapagos. Once on the different islands, adaptive radiation occurred- the finches evolved in response to the different selection pressures on the different islands.
comparative embryology (slides)
peripatric speciation
peripatric speciation occurs when a new species is formed from a subpopulation that colonies a new habitat within the same geographical area as its ancestors.
This is similar to allopatric speciation in that they are geographically separated but it differs from allopatric speciation in that it is a smaller population from the main population. This is called a subpopulation.
It could involve just a few individuals that are subject to different pressures. In time, it becomes a new species.
parapatric speciation
In parapatric speciation (3), a species is spread out over a large geographic area. Although it is possible for any member of the species to mate with another member, individuals only mate with those in their own geographic region. Like allopatric and peripatric speciation, different habitats influence the development of different species in parapatric speciation. Instead of being separated by a physical barrier, the species are separated by differences in the same environment, eg pollutants in one part of a geographical area
sympatric speciation
There are no barriers to prevent interbreeding between members of a different population. Due to different characteristics (e.g. spontaneous change in ploidy or food preferences), reproductive isolation occurs.
what is biogeography
Biogeography is the study of the distribution of species and ecosystems in geographic space and through geological time.
evolution (micro)
Microevolution is the change in allele frequencies within a single species or population, caused by natural and sexual selection, genetic drift and gene flow, generally occurring over small time scales.
Horses have undergone evolution in three major traits. Early horse ancestors were originally specialized for tropical forests, while modern horses are now adapted to life on drier land. Successive fossils show the evolution of teeth shapes and foot and leg anatomy to a grazing habit with adaptations for escaping predators.
