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Phylogenetic classification
A method of classification that reflects an organism's evolutionary history, grouping closely related organisms based on common ancestors.
Phylogenetic tree
A diagram showing evolutionary relationships, where branch points represent common ancestors and tips represent living organisms; ancestral species are shown in the trunk.
Last universal common ancestor (LUCA)
The most recent common ancestor of all life on Earth, from which all organisms have descended.
Hierarchical levels of biological classification
Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species, listed from largest to smallest.
Taxon
Discrete categories; an organism cannot belong to more than one taxon at the same level, ensuring clear classification.
Purpose of a phylogenetic classification system
To infer evolutionary relationships between organisms based on similarities, aiding in understanding their common ancestry.
Three domains of life
Eubacteria, Archaea, and Eukaryota.
Domain Eubacteria
Prokaryotic, includes bacteria like E. coli and Salmonella, with no membrane-bound organelles.
Domain Archaea
Prokaryotic, often with unusual metabolisms such as methane production, living in marginal habitats.
Domain Eukaryota
Includes all eukaryotic organisms such as plants, animals, fungi, and protoctists.
Five main kingdoms based on morphological similarities
Prokaryota, Protoctista, Fungi, Plantae, Animalia.
Characteristics of the kingdom Prokaryota
Single-celled, microscopic organisms with no membrane-bound organelles, cell wall made of peptidoglycan.
Characteristics of the kingdom Protoctista
Eukaryotic, single-celled organisms with no tissue differentiation.
Characteristics of the kingdom Fungi
Heterotrophic eukaryotes with cell walls made of chitin, reproduce by spores.
Characteristics of the kingdom Plantae
Multicellular, photosynthetic eukaryotes with cellulose cell walls.
Characteristics of the kingdom Animalia
Multicellular, heterotrophic eukaryotes with no cell wall, nervous coordination present.
Homologous structures
Structures with similar arrangement and developmental origin, indicating a common ancestor, despite different functions.
Homologous vs. analogous structures
Homologous structures have similar origin and different functions; analogous structures have similar functions but different origins.
Divergent evolution
A common ancestral limb has evolved to perform different functions in different species, such as swimming or flying.
DNA base sequence analysis
Closely related species have more similar DNA sequences; differences accumulate over time, reflecting evolutionary relatedness.
DNA hybridization
Comparing DNA fragments from two species; hybridization occurs where sequences are complementary, indicating relatedness.
Amino acid sequences
Similar amino acid sequences in proteins suggest a close evolutionary relationship, reflecting similar DNA sequences.
Immunological techniques
Mixing antigens and antibodies; closer relationships produce more precipitate due to stronger reactions.
Amino acid sequence comparison of hemoglobin
Counting common amino acids in hemoglobin molecules; more shared amino acids indicate closer evolutionary relationships.
Biological species concept
Two organisms are the same species if they can interbreed and produce fertile offspring.
Morphological species concept
Two organisms are likely the same species if they look very similar, considering features and sexual dimorphism.
Hybrids like mules
They are hybrids of different species with incompatible chromosomes or physiology, preventing fertility.
Binomial system of naming
To provide a unique, internationally recognized scientific name using genus and species, avoiding confusion from common names.
Rules for writing binomial names
Genus name capitalized and italicized or underlined; species name lowercase and italicized or underlined; genus can be abbreviated after first use.
Biodiversity
The variety of life in a given environment, including the number of species (species richness) and the number of organisms within each species.
Habitats with the highest biodiversity
Tropical rainforests and coral reefs.
Biodiversity variation with latitude
It decreases from the equator towards the poles.
Succession in an ecological context
The gradual change in community composition over time, making habitats more suitable for some species and less for others.
Natural selection in biodiversity
It generates and modifies biodiversity by favoring advantageous traits over generations.
Human influence on biodiversity
Human activities have reduced biodiversity and caused extinctions by making environments less hospitable.
Extinction
The complete loss of a species from Earth.
Fossil record and species extinction
It shows that most species are now extinct.
Causes of extinction
Change in climate or habitat, increased competition, new predators, and new diseases.
Natural rate of extinction
The normal rate is one extinction per 1 million species per year.
Human activity and extinction rates
It accelerates extinction rates between 1,000 and 100,000 times.
Greatest threat to biodiversity
Human destruction of habitat.
Conservation method involving trade
CITES bans the sale of endangered species and their parts or products.
Purpose of national parks and SSSI
To protect habitats from over-development.
Government agencies and conservation
They educate, lobby governments, raise awareness, fund projects, monitor biodiversity, and alert us to changes in risk status.
Goal of captive breeding programmes
To breed endangered species in captivity, reintroduce them into the wild, and monitor their numbers.
Function of seed banks
To research plant species and their genetic diversity, and to collect and preserve seeds of all species.
Legislation and conservation
By passing laws to protect habitats and species at risk.
Importance of species to humans
They support human civilization through food, raw materials, chemicals, pharmaceuticals, and genetic resources.
Loss from plant extinction
An incalculable loss of potential benefits and medicines.
Biodiversity index
A measure used to monitor biodiversity over time and compare different habitats, often calculated using Simpson's index.
Simpson's index
It quantifies biodiversity; higher values indicate greater biodiversity.
Calculation of Simpson's index
Using the formula S = 1 - (∑n(n-1) / N(N-1)), where N is total organisms and n is the number of each species.
Total number of organisms (N)
80
Higher Simpson's index value
Higher biodiversity.
Assessment of biodiversity using polymorphic loci
It involves examining genes and alleles to evaluate genetic diversity within a population.
Gene's locus
Its position on a chromosome.
Polymorphism in genetics
A gene has polymorphism if it has two or more alleles at frequencies greater than mutation alone.
Biodiversity of gene S and gene T
Gene S has more alleles (31) and thus higher biodiversity than gene T, which has only 2 alleles.
Proportion of alleles in a gene pool
A high proportion of the same allele indicates low biodiversity; a more even distribution indicates higher biodiversity.
Example of polymorphism in humans
The ABO blood grouping system, with alleles IA, IB, and IO.
Frequency of alleles
A more diverse distribution of alleles indicates higher genetic biodiversity.
DNA profiling
It creates a genetic fingerprint based on DNA sequences, showing similarities or differences among individuals or populations.
SNPs in DNA analysis
Single nucleotide polymorphisms, single base differences in DNA sequences.
Hyper variable regions (HVRs) or short tandem repeats (STRs)
Regions of DNA that vary in length and are repeated many times, used to compare genetic differences.
DNA profiling and biodiversity
More SNPs and HVRs lead to more variation in DNA profiles, indicating higher biodiversity.
Process of creating a DNA profile
Cutting DNA with restriction enzymes, separating fragments via electrophoresis, and analyzing banding patterns.
Genetic or DNA profile
A pattern unique to each individual, related to their DNA base sequences.
Evolution and biodiversity
It shows that biodiversity has experienced bottlenecks and mass extinctions, followed by radiations of new species.
Theory of natural selection
Proposed by Charles Darwin.
Adaptive radiation
The formation of new species from a common ancestor, such as Darwin's Galapagos finches adapting to different food sources.
Stages of natural selection
Mutation, variation, competitive advantage, survival of the fittest, reproduction, passing advantageous genes to offspring.
Natural selection and biodiversity
It favors individuals with advantageous traits, leading to a variety of adaptations and new species over time.
Mass extinction
A sudden decrease in biodiversity, often followed by the emergence of new species.
Evolution
The process by which new species are formed from pre-existing ones over long periods.
Palaeontology and evolution
It studies fossil remains to arrange extinct plants and animals in geological sequence, suggesting evolutionary relationships.
Sedimentary rocks formation
Sedimentary rocks are formed when layers of silt harden and accumulate on top of each other, creating horizontal layers called strata.
Fossils in sedimentary rocks
Each layer contains fossils typical of the time it was laid down, with the oldest rocks and fossils found in the lowest layers.
Radiometric dating
Rocks can be precisely dated using techniques that measure the decay of radioactive isotopes.
Radiocarbon method
Fossils are dated by measuring the decay of carbon-14 to estimate the age of organic remains.
Fossil record significance
The fossil record, combined with the known ages of rocks, helps scientists understand the sequence and timing of the appearance of major groups of living organisms.
Missing links
Intermediate forms expected to be found in successive rock layers between one fossil species and the next, representing transitional stages in evolution.
Creationist perspective on intermediate forms
Creationists believe that the rarity of intermediate forms is evidence of special creation or intelligent design, rather than evolution.
Eldridge and Gould's interpretation of rapid speciation
They suggest that new species may arise rapidly, within a few thousand years, and then remain unchanged for millions of years, making intermediate forms in the fossil record rare.
Adaptation
The change in a species where useful characteristics become more common.
Adaptive traits
The useful characteristics that increase an organism's chances of survival and reproduction.
Anatomical traits
Physical features that can be adaptive, such as streamlined bodies in sharks, dolphins, and penguins that aid in efficient movement and hunting.
Physiological traits
Internal body functions that help organisms adapt, such as hibernation in polar bears, where body temperature drops to conserve energy.
Behavioral traits
Actions or behaviors that increase survival or reproductive success, such as hawthorn flowering in spring to coincide with pollinator emergence.
Hibernation
Allows animals like hedgehogs to survive winter when food is scarce by lowering their body temperature and metabolic rate.
Penguin's streamlined body
An anatomical adaptive trait that reduces water resistance, aiding in efficient swimming.
Peacock's tail display
Peacocks display their magnificent tails to attract mates, increasing their chances of reproductive success.
Gas exchange
The process of exchanging gases with the environment across respiratory surfaces.
Characteristics of a respiratory surface
A respiratory surface must be thin, permeable to gases, moist, and have a large surface area.
Amoeba gas exchange
Amoeba, being a single cell, has a large surface area to volume ratio and a thin cell membrane, allowing gases to diffuse directly across the cell surface efficiently.
Flatworms gas exchange
Flatworms facilitate gas exchange due to their flat shape, which shortens diffusion distances and enhances gas exchange.
Earthworms gas exchange mechanism
Earthworms rely on their moist skin as the respiratory surface where oxygen diffuses through the skin into blood capillaries.
Earthworms oxygen requirement
Earthworms have a low metabolic rate and move slowly, requiring less oxygen.
Bony fish specialized gas exchange surface
Bony fish have gills with large surface areas due to gill filaments and lamellae.
Water movement over fish gills
Water is forced over the gills by a ventilating mechanism involving pressure changes in the buccal and opercular cavities.
Ventilation process in bony fish
Ventilation involves three stages: opening the mouth to draw water in, closing the mouth and forcing water over the gills, and opening the operculum to expel water.