Ecology, Systematics, and Evolutionary Biology

Flashcards testing core concepts, definitions, taxa, equations, and evolutionary mechanisms from the Ecology and Systematics lecture notes.

What are emergent properties in ecological systems?

Emergent properties are characteristics that arise during the transition from a lower level of biological complexity to a higher one, which are not simply the sum of the characteristics of individual lower-level elements.

What is the difference between a habitat and an ecological niche?

A habitat is a place whose abiotic characteristics allow a given species to live, develop, and reproduce. An ecological niche is the specific role and functions that a species performs in its habitat, including its resource usage, predators, and competitors.

What is the currently most widely used definition of a species?

A species is a group of natural populations whose individuals can interbreed with each other, giving rise to fertile offspring.

Why is a mule a sterile hybrid?

A mule results from crossing a male donkey ($2n = 62$) and a mare ($2n = 64$), giving an odd chromosomal complement of $63$ chromosomes, which fails to pair properly during meiosis.

What are the five types of prezygotic isolation mechanism described in the text?

Habitat isolation, temporal isolation, behavioral isolation, mechanical isolation, and gametic isolation.

Who proposed binomial nomenclature, and what are its two components?

Carl von Linné (1707-1778) proposed it in Systema Naturae. The two components are the name of the Genus (e.g., Felis) and a second specific term (e.g., catus) that distinguishes the species.

What is the hierarchical sequence of classification categories from broadest to most specific?

Domain, Kingdom, Phylum (or Division), Class, Order, Family, Genus, Species. PAV= Domani Kevin Porta COn se la sua FiGa Spagnola

What are the four fundamental shapes of bacteria?

Coccus (spherical or spheroidal), Bacillus (rod-shaped), Spirillum (spiral-shaped), and Vibrio (comma- or C-shaped).

Which pathogenic protists cause malaria and sleeping sickness?

Malaria is caused by Plasmodium falciparum (among others), and sleeping sickness (Trypanosomiasis) is caused by Trypanosoma cruzi.

Based on this leaf cross-section diagram, what are the roles of the stoma and guard cells?

The stoma is a small pore located predominantly on the lower leaf surface that permits gaseous exchanges ($CO_2$ and $O_2$), regulated by the surrounding guard cells that open and close the pore.

What are the two types of plant vascular tissue and their functions?

Xylem transports raw sap (water and mineral salts), and phloem transports processed sap (containing sugars).

What are the five main types of plant cells?

Parenchyma, Collenchyma, Sclerenchyma, cells conducting raw sap (tracheids and vessel elements), and cells conducting processed sap (sieve tubes).

What distinguishes Gymnosperms from Angiosperms?

Gymnosperms have naked seeds contained in specific structures like cones without flowers or fruits, whereas Angiosperms produce flowers or fruits that enclose their seeds.

How are Crustaceans, Arachnids, and Insects distinguished by leg count?

Insects have $6$ legs ($3$ pairs), Arachnids have $8$ legs ($4$ pairs), and Crustaceans have up to $10$ pairs of legs.

What are the three main sub-groups of mammals?

Prototherians (Monotremes, egg-laying), Metatherians (Marsupials, possessing a marsupium), and Eutherians (Placentals, forming a true placenta).

What distinguishes Mysticetes from Odontocetes within Cetaceans?

Mysticetes possess keratinous baleen plates for filtering and are larger (e.g., blue whales, humpbacks), whereas Odontocetes possess teeth and are generally smaller (e.g., dolphins, orcas, sperm whales).

Classify Tuberculosis, Syphilis, Rabies, and Poliomyelitis as bacterial or viral diseases.

Tuberculosis and Syphilis are bacterial diseases; Rabies and Poliomyelitis are viral diseases.

What defining soil layer characterizes the Tundra biome?

Permafrost, a layer of permanently frozen soil where only the uppermost portion thaws during the brief summer.

What is the difference between Gross Primary Productivity and Net Primary Productivity?

Gross primary productivity is the rate at which solar or chemical energy is converted into organic matter by primary producers, whereas net primary productivity is gross primary productivity minus the energy lost through respiration.

What are the primary gaseous components of the troposphere?

Nitrogen ($78\text{\%}$) and Oxygen ($21\text{\%}$).

What happens during nitrogen fixation and denitrification in the nitrogen cycle?

In nitrogen fixation, atmospheric nitrogen ($N_2$) is converted into ammonia ($NH_3$) or ammonium salts by bacterial activity. In denitrification, denitrifying bacteria transform nitrates back into atmospheric $N_2$.

What were Jean Baptiste Lamarck's two main evolutionary principles proposed in 1809?

The "law of use and of disuse" (frequently used organs develop while unused ones shrink) and the "law of the inheritance of acquired characters" (acquired traits are passed to offspring).

How did Thomas Malthus's work contribute to Darwin's theory of natural selection?

Malthus observed that human population growth outpaces food supply, causing a struggle for resources. Darwin applied this to all biological species, concluding that environmental limits select which individuals survive and reproduce.

What is the difference between homologous and analogous structures?

Homologous structures share a common evolutionary origin and underlying structural pattern despite differing functions (e.g., vertebrate forelimbs). Analogous structures share similar functions without a common ancestral origin (e.g., bird wings and butterfly wings).

How does the model of punctuated equilibria differ from the gradual model of speciation?

The gradual model predicts speciation occurs slowly and continuously in isolated populations. The punctuated equilibria model (Eldredge and Gould, 1972) states that long equilibrium periods are interrupted by rapid speciation events.

What is the main difference between allopatric and sympatric speciation?

Allopatric speciation (Ernst Mayr, 1942) requires a geographic barrier isolating subpopulations. Sympatric speciation occurs within the same geographic region without physical isolation, often through genetic polymorphism or polyploidy.

What is the Hardy-Weinberg equation for a gene with two alleles ($A$ and $a$)?

The equation is $p^2 + 2pq + q^2 = 1$, where $p$ is the frequency of allele $A$, $q$ is the frequency of allele $a$, $p^2$ is the frequency of genotype $AA$, $2pq$ is the frequency of genotype $Aa$, and $q^2$ is the frequency of genotype $aa$.

What five conditions must be fulfilled to maintain Hardy-Weinberg equilibrium in a population?

1. Random mating; 2. Large population size; 3. No gene flow (no immigration or emigration); 4. No mutations; 5. No natural selection affecting genotypes.

What are the effects of stabilizing, directional, and divergent natural selection on phenotype distributions?

Stabilizing selection favors intermediate phenotypes and reduces variability; directional selection favors one extreme phenotype and shifts the population mean; divergent selection favors both extreme phenotypes over intermediate ones, increasing variability.

What is the difference between the Founder Effect and the Bottleneck Effect in genetic drift?

The Founder Effect occurs when a small group of pioneer individuals colonizes a new region carrying only a subset of the source population's alleles. The Bottleneck Effect occurs when a population undergoes severe numerical contraction due to hardship or catastrophe, randomly altering allele frequencies.