Key terms exam 4

Asexual Reproduction

Formation of new individuals without the fusion of gametes, resulting in offspring that are genetically identical to the parent.

Sexual Reproduction

Formation of embryos through the fusion of two haploid gametes, requiring genetic contribution from two distinct individuals.

Fission

Separation of an individual into two or more parts of roughly equal size, each growing into a new organism.

Fragmentation

Breaking off of a body part that can regenerate and develop into a wholly new individual.

Budding

Formation of a new individual as an outgrowth from the parent organism.

Stolon

Structures from which new individuals can grow, leading to colonial forms.

Parthenogenesis

Development of a new individual from an unfertilized egg, which can be obligate or facultative.

Gonochoristic

Species characterized by separate male and female individuals, producing only one type of gamete.

Hermaphroditic

An organism capable of producing both sperm and eggs at some point in its life.

Outcrossing

Cross-fertilization between genetically distinct individuals, promoting genetic diversity.

Genetic Sex Determination

System where the sex of an offspring is determined by genes or chromosomes inherited from parents.

Environmental Sex Determination (TSD)

System where the sex of an offspring is determined by environmental factors, like incubation temperature.

Wolffian Duct

Embryonic duct that develops into male reproductive structures in the presence of testosterone.

Müllerian Duct

Embryonic duct that develops into female reproductive structures in the absence of Anti-Müllerian Hormone.

Oviduct

Part of the female reproductive tract that transports eggs from the ovary to the uterus.

Ductus Deferens (Vas Deferens)

Part of the male reproductive tract that transports sperm from the epididymis to the ejaculatory duct.

Gametogenesis

Process by which precursor cells undergo division and differentiation to form mature gametes.

Oogenesis

Process of egg production in females occurring in the ovaries.

Spermatogenesis

Process of sperm production in males occurring continuously in the testes.

Broadcast Spawning

A reproductive strategy where marine animals release gametes directly into water for fertilization.

Amplexus

Mating embrace in frogs ensuring close proximity of gametes for fertilization.

External Fertilization

Fertilization occurring outside the body of parents, usually in an aquatic environment.

Internal Fertilization

Fertilization occurring within the female reproductive tract.

Modes for Attracting Mates

Various strategies animals use to secure a mate, including signals and courtship displays.

Sexual Dimorphism

Physical differences between males and females of a species beyond reproductive organs.

Sequential Hermaphroditism

When individuals can change sex over their lifespan to optimize reproductive output.

r-strategy (r-selected species)

Life history strategy characterized by producing many offspring with low parental investment.

K-strategy (K-selected species)

Life history strategy characterized by producing fewer offspring with high parental investment.

Oviparity

Reproductive mode where offspring develop in eggs laid outside the mother's body.

Viviparity

Reproductive mode where offspring develop inside the mother and are born live.

Parental Care

Behaviors by parents to increase the fitness of their offspring.

Trade-offs (in reproductive strategies)

Compromises in resource allocation between different life history traits.

Gastrulation

Stage in early embryonic development where the blastula is reorganized into the gastrula.

Blastopore

Indentation in the gastrula where cells invaginate during gastrulation.

Embryonic Germ Layers

Three primary cell layers (ectoderm, mesoderm, endoderm) formed during gastrulation.

Organogenesis

Process during embryonic development where germ layers differentiate into organs.

Determinants of Developmental Patterns

The combined effects of genetic and environmental factors shaping development.

Epigenetics

Heritable changes in gene expression occurring without changes in DNA sequence.

Phenotypic Plasticity

Ability of a genotype to produce different phenotypes in response to environmental changes.

Phenotypic Canalization

Tendency of a phenotype to remain constant despite genetic or environmental variation.

Significance of Transplant Experiments

Experiments demonstrating embryonic induction and the robustness of developmental instructions.

Cell Fates

Developmental destiny of a cell, referring to its differentiation into specific cell types.

Stem Cells

Undifferentiated cells that can self-renew and differentiate into specialized cell types.

Pluripotent Stem Cells

Stem cells that can differentiate into any cell type but not into extraembryonic tissues.

Multipotent Stem Cells

Stem cells restricted to differentiating into specific lineages within a tissue.

Cancer

Disease characterized by uncontrolled proliferation and metastasis of abnormal cells.

Transmissible Cancers

Rare cancers that can spread directly between individuals through cancerous cells.

Hormones

Chemical messengers secreted into the bloodstream to elicit physiological effects.

Endocrine System

Regulatory system composed of glands producing hormones to communicate signals.

Endocrine Glands

Ductless glands that secrete hormones directly into the bloodstream.

Positive Feedback

Regulatory mechanism where output enhances the initial stimulus.

Negative Feedback

Regulatory mechanism where output inhibits the initial stimulus to maintain homeostasis.

Thyroid hormone and effects

Regulates metabolism, growth, and development requiring iodine for synthesis.

Bioenergetics

Study of energy flow and transformations in living organisms.

Metabolism

Sum total of all chemical reactions occurring within an organism.

Anabolism

Constructive metabolism involving energy-requiring processes that build complex molecules.

Catabolism

Destructive metabolism that breaks down complex molecules and releases energy.

Diffusion

Tendency for molecules to evenly distribute across a space.

Passive transport

Movement of molecules across membranes without energy input.

Osmosis

Diffusion of water across selectively permeable membranes.

Transport epithelium

Specialized cells managing salt and ion transport.

Hemolymph

Circulatory fluid in open systems, a mix of blood and interstitial fluid.

Urea

Less toxic nitrogenous waste suitable for both aquatic and terrestrial organisms.

Uric Acid

Least toxic nitrogenous waste, requiring the most energy to produce.

Gill filaments

Feathery structures in fish supporting the respiratory surface.

Alveoli

Microscopic air sacs in lungs providing a large surface area for gas exchange.

Neurons

Specialized cells that transmit nerve impulses.

Neurotransmitters

Chemical messengers facilitating communication between neurons.

Central Nervous System (CNS)

Comprises the brain and spinal cord, processing information and initiating responses.

Peripheral Nervous System (PNS)

Connects the CNS to the rest of the body, including sensory and motor pathways.

Action potential

Electrical current generated when a neuron is stimulated.

Astrocytes

Glial cells providing support and maintaining the chemical environment for neurons.

Neuroplasticity

Ability of the nervous system to change in response to experience.