Biology Chapter: Modes of Reproduction

The process of duplicating DNA, requiring an additional cellular structure to support new DNA copies.

The process of one cell splitting into two, each containing its own DNA copy and cellular apparatus.

Small differences in the copied DNA, arising from inevitable imperfections in the copying process.

A new cell with a drastically altered DNA copy during reproduction may not survive given the cellular apparatus it inherits.

The built-in tendency for changes in DNA copies during reproduction.

Variation during reproduction forms the basis for evolution, allowing populations to adapt to changing environments.

DNA's consistent copying supports the overall form of an organism, enabling it to fill a precise niche within an ecosystem.

Ecosystem changes (like temperature shifts, water changes, and meteor events) can alter the conditions that organisms in a specific niche need to persist.

Populations with variations are more likely to survive significant environmental changes, as some individuals may have traits that help them adapt.

Significant shifts in an environment, like increasing water temperature, can negatively affect an entire population.

Existing species can evolve and adapt over time through advantageous variations, enabling their survival when environmental pressures shift.

Simple cell division, or fission, is a method of reproduction in single-celled organisms (like bacteria and protozoa) where the cell splits into two.

In Amoeba, a type of protozoa, the splitting during cell division can occur in any direction.

Yeast can be observed growing in specific environmental conditions, like warm places.

Mold can be observed growing on moist bread in cool, dark, and moist environments.

Variation within a species is beneficial for survival of the entire species by providing individuals with traits useful for adaptation.

A method of reproduction where a single-celled organism, like Amoeba, splits into two new individuals.

A type of cell division where a single cell divides into many daughter cells simultaneously, observed in some single-celled organisms like Plasmodium.

A form of asexual reproduction where an organism breaks into fragments, each fragment growing into a new individual, like Spirogyra.

Yeast reproduces through budding, where new cells develop from the parent cell in the form of small buds that eventually detach and grow.

A type of unicellular organisms that have a specific orientation for binary fission.

Complex reproduction methods are required in multicellular organisms (compared to unicellular organisms), due to the organized arrangement of cells, tissues and organs

Spirogyra, a type of algae, reproduces by fragmentation, where the filament breaks into pieces, each fragment growing into a new individual.

Techniques like binary fission and fragmentation are employed in organisms without highly structured bodies.

Reproduction involving two individuals (male and female) combining their DNA to create a new generation.

Creates variations in offspring, increasing chances of survival if the environment changes.

Asexual reproduction produces identical copies, making the whole population vulnerable to environmental changes.

Errors in DNA copying result in variations, which are important for the survival of a population or species.

Variations in DNA are important for a species' ability to adapt and survive in changing environments.

Complex organisms often lack the ability for significant regeneration because their body structures are more intricate than simpler organisms.

Planting cuttings or parts of plants to grow new individuals, useful for preserving desired traits.

Accurate copying of DNA is crucial for producing a new individual with the same genetic instructions as the original.

Transfer of pollen within the same flower

Transfer of pollen between flowers

Seeds contain future plants (embryos), enabling survival & reproduction

Process where seed develops into a seedling

Reproduction involving male and female combining DNA

Changes in size and characteristics (physical features)

Tube growing from pollen grain to reach the ovary's female cells.

The steps from fertilization to seed development.

Methods used to prevent pregnancy.

Prevent sperm from reaching the egg by creating a physical barrier.

Prevent ovulation and fertilization by altering the body's hormone balance.

Surgical procedures to block fallopian tubes or vas deferens, preventing fertilization.

Uneven distribution in the number of males and females in a population.

Methods to determine the sex of a fetus before birth.

Concerns about the size of the human population and its impact on resources.

The rate of birth and death in a population determine its size.