Exam 2

Hardy-Weinberg Equilibrium

A principle that provides the conditions under which allele frequencies remain constant in a population.

Genetic Drift

Random changes in allele frequencies in a population, especially significant in small populations.

Bottleneck Effect

A significant reduction of a population's gene pool, leading to decreased genetic diversity.

Gene Flow

The movement of individuals and alleles between populations, often leading to increased genetic diversity.

Monohybrid Cross

A genetic cross between parents that differ in a single trait, leading to offspring with varying genotypes.

Allele Frequency

The relative frequency of an allele at a genetic locus in a population.

Natural Selection

The process by which traits that enhance survival and reproduction become more common in subsequent generations.

Speciation

The evolutionary process by which populations evolve to become distinct species.

Inbreeding Depression

A reduction in fitness and genetic diversity due to mating between closely related individuals.

Phylogenetic Tree

A branching diagram that depicts evolutionary relationships among various species based on shared characteristics.

Biological Species Concept

A definition of species based on the ability to interbreed and produce viable offspring.

Morphospecies Concept

A method of classifying species based on morphological characteristics.

Punctuated Equilibrium

An evolutionary hypothesis stating that species are generally stable and change rapidly during periods of speciation.

Protostome

An organism whose mouth develops from the blastopore during embryonic development.

Deuterostome

An organism whose anus develops from the blastopore during embryonic development.

Echinoderm

A phylum of marine animals that includes sea stars and sea urchins, characterized by radial symmetry and a calcareous endoskeleton.

Chordata

The phylum that includes all animals with a notochord, including vertebrates.

Angiosperms

A group of flowering plants that produce seeds enclosed within a fruit.

Gymnosperms

A group of seed-producing plants that do not form flowers or fruits, such as conifers.

Vascular Plants

Plants that possess specialized tissue (xylem and phloem) for the transport of water and nutrients.

Non-Vascular Plants

Plants that lack vascular tissue, such as mosses and liverworts.

Metabolism

The set of life-sustaining chemical reactions in organisms.

Sympatric Speciation

The emergence of new species from a single ancestral species while inhabiting the same geographic region.

Allopatric Speciation

The formation of a new species due to geographic separation.

What is the definition of 'ecosystem'?

An ecosystem is a community of living organisms interacting with their physical environment.

What is 'biodiversity'?

Biodiversity refers to the variety of living species on Earth, including plants, animals, fungi, and microorganisms.

What are 'food chains'?

Food chains describe the flow of energy and nutrients through an ecosystem, connecting producers, consumers, and decomposers.

What is a 'producer' in an ecosystem?

Producers are organisms that can create their own food through photosynthesis or chemosynthesis, such as plants and some bacteria.

Define 'pollination'.

Pollination is the transfer of pollen from the male part of a flower to the female part, facilitating fertilization.

What are 'keystone species'?

Keystone species are organisms that have a disproportionately large impact on their environment relative to their abundance.

What is 'habitat fragmentation'?

Habitat fragmentation occurs when large habitats are divided into smaller, isolated patches, often due to human activities.

Describe 'climate change'.

Climate change refers to long-term shifts and alterations in temperature and weather patterns, primarily driven by human activities.

What is an 'invasive species'?

Invasive species are non-native organisms that, when introduced to a new environment, can disrupt local ecosystems.

What is 'sustainable development'?

Sustainable development is the practice of meeting current needs without compromising the ability of future generations to meet theirs.

What is the Hardy-Weinberg principle?

The Hardy-Weinberg principle states that allele and genotype frequencies in a population will remain constant from generation to generation in the absence of evolutionary influences.

List the five conditions required for Hardy-Weinberg equilibrium.

1. No mutations
2. Random mating
3. No natural selection
4. Extremely large population size
5. No gene flow (migration in or out of the population)

What does the Hardy-Weinberg equation predict?

The Hardy-Weinberg equation (p^2 + 2pq + q^2 = 1) predicts the genotype frequencies in a population based on allele frequencies.

What do the variables p and q represent in the Hardy-Weinberg equation?

In the Hardy-Weinberg equation, p represents the frequency of the dominant allele, and q represents the frequency of the recessive allele.

What is the significance of the Hardy-Weinberg principle in population genetics?

The Hardy-Weinberg principle serves as a null hypothesis for studying evolutionary processes and helps identify factors causing changes in allele frequencies.

How does natural selection affect Hardy-Weinberg equilibrium?

Natural selection disrupts Hardy-Weinberg equilibrium by favoring certain alleles over others, changing allele frequencies in a population over time.

What is allele frequency?

Allele frequency refers to how often a particular allele appears in a population compared to other alleles for the same gene.

Define genotype frequency.

Genotype frequency is the proportion of individuals in a population that carry a specific genotype for a given gene.

What does p^2 represent in the Hardy-Weinberg equation?

In the Hardy-Weinberg equation, p^2 represents the expected frequency of homozygous dominant individuals in the population.

What does 2pq represent in the Hardy-Weinberg equation?

In the Hardy-Weinberg equation, 2pq represents the expected frequency of heterozygous individuals in the population.

What does q^2 represent in the Hardy-Weinberg equation?

In the Hardy-Weinberg equation, q^2 represents the expected frequency of homozygous recessive individuals in the population.

Explain what is meant by 'genetic drift'.

Genetic drift is the random fluctuation in allele frequencies in a population, which can have a significant effect in small populations.

What is gene flow?

Gene flow is the transfer of alleles or genes from one population to another, which can introduce new genetic material into a population.

Define 'mutation' in the context of genetics.

A mutation is a change in the DNA sequence of an organism's genome, which can lead to new traits and variations in a population.

Define phenotype.

Phenotype refers to the observable traits or characteristics of an organism, resulting from the interaction of its genotype and the environment.

What is a homozygous genotype?

A homozygous genotype has two identical alleles for a specific gene, either dominant or recessive (e.g., AA or aa).

What is a heterozygous genotype?

A heterozygous genotype has two different alleles for a specific gene, one dominant and one recessive (e.g., Aa).

Define zygote.

A zygote is the fertilized egg formed when two gametes (sperm and egg) combine, marking the beginning of development of a new organism.

What is natural selection?

Natural selection is the process by which organisms better adapted to their environment tend to survive and produce more offspring.

Explain evolutionary fitness.

Evolutionary fitness refers to an organism's ability to survive and reproduce, contributing its genes to the next generation compared to others in the population.

What is a selective pressure?

Selective pressure is an environmental factor that influences the survival and reproduction of individuals in a population, leading to evolutionary changes.

Define speciation.

Speciation is the process by which new species arise due to evolutionary mechanisms such as isolation, genetic drift, and natural selection.

What is the process by which plants convert sunlight into energy?

Photosynthesis is the process used by green plants and some other organisms to transform sunlight into chemical energy, mainly converting carbon dioxide and water into glucose and oxygen.

What is the significance of chlorophyll in plants?

Chlorophyll is the green pigment essential for photosynthesis, enabling plants to capture light energy from the sun to produce food.

What are stomata and their function in plants?

Stomata are tiny openings on leaves' surfaces that facilitate gas exchange; they allow carbon dioxide to enter and oxygen and water vapor to escape.

What does vascular tissue do in plants?

Vascular tissue refers to the specialized plant tissue that transports water, nutrients, and sugars, comprising xylem and phloem.

What characterizes angiosperms?

Angiosperms are a group of flowering plants that produce seeds encased within a fruit, and they are the most diverse category of plants.

How do gymnosperms differ from angiosperms?

Gymnosperms are non-flowering plants that yield seeds not enclosed by an ovary or fruit, such as those found in coniferous trees like pines.

What is the function of roots in plant structure?

Roots serve to anchor the plant in soil, absorb water and nutrients, and act as a storage organ for energy and minerals.

What is the purpose of tissue culture in plant science?

Tissue culture is a method used to grow plants in a sterile environment using small pieces of plant tissue to generate clones of the original plant.