Biology: Spring Semester Review

What are the steps for the process of meiosis?

Meiosis I (Prophase I, Metaphase I, Anaphase I, Telophase I) and Meiosis II (Prophase II, Metaphase II, Anaphase II, Telophase II). Each phase involves specific events like chromosome condensation, crossing over, alignment, and separation.

What do you call the combination of all of the alleles in a population?

Gene pool

What does a normal distribution curve look like?

Bell-shaped curve, with most individuals falling near the average and fewer individuals at the extremes.

What are the differences between convergent and divergent evolution?

Convergent evolution: unrelated species develop similar traits due to similar environmental pressures. Divergent evolution: related species evolve different traits due to different environmental pressures.

What is coevolution?

The process where two or more species reciprocally affect each other's evolution. Examples: predator-prey relationships, plant-pollinator relationships.

Why can't mutations in body cells be a source of genetic variation?

Mutations in body cells (somatic cells) are not passed on to offspring, therefore they do not contribute to genetic variation in a population.

Define homologous chromosomes.

Pairs of chromosomes (one from each parent) that have the same genes in the same order.

Define sister chromatids.

Two identical copies of a single chromosome that are connected by a centromere.

Define centromere.

The region of a chromosome to which the microtubules of the spindle attach during cell division.

What is the location of genes on a chromosome called?

Locus (plural: loci)

What is the product of meiosis in terms of chromosome number?

Cells with half the number of chromosomes as the original cell (haploid).

How many cells are made by the end of meiosis?

Four

What are the cells made by meiosis called?

Gametes (sperm or egg cells)

Are the cells made in meiosis the same or different from each other?

Different

What is crossing over?

The exchange of genetic material between homologous chromosomes during prophase I of meiosis, leading to genetic variation.

When does crossing over take place?

Prophase I of meiosis

Who determines the gender of a child?

The father; males have XY chromosomes, so they can contribute either an X or a Y chromosome, whereas females have XX chromosomes and can only contribute an X chromosome.

Who is considered the father of modern genetics?

Gregor Mendel

What is complete dominance?

A form of inheritance in where one allele completely masks the effect of the other allele in heterozygous condition

What is incomplete dominance?

A form of inheritance in where the heterozygous condition produces a phenotype that is intermediate between those of the parents.

What is co-dominance?

A form of inheritance in where both alleles are equally expressed in the heterozygous condition.

What is multiple alleles?

A form of inheritance in where a gene has more than two possible alleles in a population.

What is sex-linked inheritance?

A form of inheritance in where a gene is located on a sex chromosome (X or Y).

What does it mean to be a carrier for a trait?

To carry a recessive allele for a trait without expressing it (typically refers to heterozygous individuals for autosomal recessive traits or females for X-linked recessive traits).

Who is more likely to be a carrier for a sex-linked trait, male or female?

Female

When can a woman express a recessive sex-linked disorder?

When she is homozygous recessive for the trait (i.e., has two copies of the recessive allele).

What is a testcross?

Mating an individual of unknown genotype with a homozygous recessive individual to determine the unknown genotype.

What is a dihybrid cross?

A cross between two individuals that are heterozygous for two different traits.

What is polygenic inheritance?

A form of inheritance in where a trait is controlled by multiple genes.

Define heterozygous

Having two different alleles for a particular gene.

Define homozygous

Having two identical alleles for a particular gene.

What is a karyotype?

A display of an individual's chromosomes, arranged in homologous pairs and ordered by size; it can reveal chromosomal abnormalities.

What is a pedigree?

A diagram that shows the inheritance of a trait in a family, used to determine whether a trait is dominant or recessive and whether it is sex-linked or autosomal.

What is the difference between genotype and phenotype?

Genotype: the genetic makeup of an individual. Phenotype: the observable characteristics of an individual, resulting from the interaction of its genotype with the environment.

What are the components of a DNA nucleotide?

Deoxyribose sugar, phosphate group, and a nitrogenous base (adenine, guanine, cytosine, or thymine).

What types of bonds hold the two strands of DNA together at the nitrogen bases?

Hydrogen bonds

What type of bonds hold the sides of the DNA ladder together?

Phosphodiester bonds

What nitrogen bases can be found in DNA?

Adenine (A), guanine (G), cytosine (C), and thymine (T)

Where does DNA live in eukaryotic cells?

Nucleus

What is the process that makes more molecules of DNA?

Replication

What are the main differences between DNA and RNA?

DNA: double-stranded, deoxyribose sugar, contains thymine, cannot leave the nucleus. RNA: single-stranded, ribose sugar, contains uracil, can leave the nucleus.

Where does replication take place?

Nucleus

Where does transcription take place?

Nucleus

Where does translation take place?

Cytoplasm (ribosomes)

What are the important components of Splicing (RNA editing)?

Introns and exons. Introns stay in the nucleus and get broken apart. Exons get put back together and exit nucleus as a complete piece of RNA.

What is the complement for DNA?

A pairs with T, G pairs with C

What is the complement for RNA?

A pairs with U, G pairs with C

What is the central dogma of molecular biology?

DNA -> RNA -> Protein

Which two scientists are credited with finding out the structure of the DNA molecule?

James Watson and Francis Crick

What features help a species to survive better in its environment?

Adaptations

Who is Linnaeus and what does his system of taxonomy mean?

Carolus Linnaeus was a Swedish botanist, physician, and zoologist, who formalised binomial nomenclature, the modern system of naming organisms.

What are the 5 aspects of Darwin’s theory of evolution by natural selection?

Overproduction, variation, competition, survival and reproduction, and speciation.

What are the differences between natural and artificial selection?

Natural Selection: Environmental factors determine which traits are beneficial. Artificial Selection: Humans determine which traits are beneficial.

What are the ultimate sources of genetic variability in population?

Mutations and sexual reproduction.

What is embryology and how can this be helpful in adding evidence for evolution?

Embryology is the study of the development of embryos, including those of animals and plants. Scientists can look at the similarities in the development stages to show relationships between organisms.

What are the differences between homologous and analogous structures?

Homologous Structures: Structures that are similar due to shared ancestry but may have different functions. Analogous Structures: Structures that are similar in function but have different evolutionary origins.

Which level of organisms does natural selection act on?

Individuals

Which level of organisms does evolution act on?

Populations

What is gene flow?

The transfer of genetic variation from one population to another.

What is genetic drift?

A change in the allele frequency of a population as a result of chance events rather than natural selection.

What is the founder effect?

A type of genetic drift that occurs when a small group of individuals establishes a new population, leading to a loss of genetic variation.

What is the bottleneck effect?

A type of genetic drift that occurs when a population's size is drastically reduced, leading to a loss of genetic variation.

What are the three types of reproductive isolation?

Geographic, behavioral, and temporal isolation.

What are the differences between micro and macroevolution?

Microevolution: changes in allele frequencies within a population over time. Macroevolution: the evolution of new species and higher taxonomic groups.

What does it mean when a species is said to be extinct?

The termination of a species or higher taxonomic group, meaning that there are no longer any living individuals.

Know how to read a cladogram; know how to read a phylogenetic tree; know what is meant by a common ancestor (how can you tell where the common ancestor is for a set of organisms)

Refer to the diagrams.

What are the different modes of evolution?

Disruptive, stabilizing, and directional.

What are the different types of selection?

Intersexual (mate choice) and intrasexual (competition within the same sex).

What is adaptive radiation?

The diversification of a group of organisms into different ecological niches over a relatively short period of time.

What does H-W Eq. mean for a population?

It means that the population is not evolving and that the allele and genotype frequencies are stable from generation to generation.

What does it mean for a population to not be in H-Q Eq.?

A population not in Hardy Queinberg equilibrium means that the population is experiencing evolutionary change due to factors such as mutation, nonrandom mating, gene flow, genetic drift, or natural selection.

What are the five conditions that need to be satisfied to be in H-Q Eq.?

No mutation, random mating, no gene flow, no genetic drift, and no natural selection.

What Domains encompass bacteria?

Bacteria and Archaea

What Domain encompasses eukaryotic organisms?

Eukarya

What is the molecule of photosynthesis and why is it green?

Chlorophyll is the primary pigment involved in photosynthesis. It appears green because it absorbs red and blue light while reflecting green light.

What is the difference between pollination and fertilization?

Pollination: The transfer of pollen from the male part of a flower (anther) to the female part (stigma). Fertilization: The fusion of male and female gametes (sperm and egg) to form a zygote.

Which organism provides a majority of the energy in an ecosystem?

Producers (autotrophs)

What are you measuring when you are looking at the biodiversity of an ecosystem?

The variety of life in that ecosystem, including the variety of species, genes, and ecosystems present.

What is a population?

A group of individuals of the same species living in a particular area.

What is an ecosystem?

A community of living organisms (biotic factors) interacting with their physical environment (abiotic factors).

What are examples of population characteristics?

Density, dispersion, age structure, birth rate, and death rate.

What is the difference between a generalist and a specialist?

Generalist: A species that can thrive in a wide variety of environmental conditions and make use of a variety of resources. Specialist: A species that can thrive only in a narrow range of environmental conditions or has a limited diet.

What is a special specialist?

A keystone species.

What can happen to an ecosystem if keystone species are lost from it?

Ecosystems may collapse.

What types of factors can be altered if a keystone species is lost from a system?

Biodiversity, ecosystem structure, and ecosystem function.

What are the four different types of interspecific interactions?

Mutualism, commensalism, predation, and competition

What is symbiosis?

A close and long-term interaction between two different species.

Which interactions fall under symbiosis?

Mutualism, commensalism, and parasitism.

What are the two factors that will increase a population?

Birth and immigration.

What are the two factors that will decrease a population?

Death and emigration.

What is the difference between a density-dependent factor and a density-independent factor?

Density-dependent factor: A factor that affects population growth more strongly as population density increases (e.g., competition, predation, disease). Density-independent factor: A factor that affects population growth regardless of population density (e.g., natural disasters, weather).

What can happen when two species compete?

Competitive exclusion, resource partitioning, or character displacement.

What is an ecological equivalent?

Species that occupy similar ecological niches in different geographic regions.

What is population density?

The number of individuals per unit area or volume.

What are the differences between primary and secondary succession?

Primary succession: Succession that occurs in an area where no soil exists (e.g., after a volcanic eruption). Secondary succession: Succession that occurs in an area where soil already exists (e.g., after a fire or flood).

What is a pioneer species?

The first species to colonize a barren area during primary succession.

What is a climax community?

A stable and mature community that has reached a state of equilibrium after succession.

What determines the climax community for an area?

Climax state/stability is brought on by a complex web of environmental factors (regional climate, soil conditions, availability of water), which eventually lead to a condition with dynamic equilibrium.

What is an invasive species?

A species that is introduced to a new environment and causes harm to the native ecosystem, economy, or human health.

What is the main difference in terms of how matter moves around Earth and how energy moves around Earth?

Matter cycles, energy flows.