Variation and Evolution Flashcards

Flashcards on Variation and Evolution

Sexual Reproduction

Reproduction involving two parents where gametes combine, leading to genetic variation in offspring.

Asexual Reproduction

Reproduction involving one parent producing genetically identical offspring (clones), with no genetic variation.

Genetic Variation

Differences between members of the same species due to genetic factors inherited from parental DNA, like eye color or blood type.

Environmental Variation

Differences between members of the same species caused by environmental factors, such as language development or access to resources.

Evolution

The process by which heritable variations in species allow them to adapt to their environment over time, driven by natural selection.

Mutation

Random changes in genes that cause variations in species; the rate can be increased by ionizing radiation.

Continuous Variation

Variation controlled by more than one gene and environmental factors, showing a range of values (e.g., height and weight).

Discontinuous Variation

Variation usually controlled by one gene, where individuals fall into distinct groups (e.g., eye color, blood type).

Cystic Fibrosis

A genetically inherited disease caused by a recessive gene, leading to thick, sticky mucus that blocks bronchioles in the lungs.

Survival of the Fittest

The concept that organisms with advantageous genes are better adapted to compete for resources or survive toxins, passing on these genes to the next generation.

Extinction

The disappearance of a species when environmental change is too rapid for it to adapt through natural selection.

DNA Base Pairing

The specific pairing of bases in DNA: Guanine (G) pairs with Cytosine (C), and Adenine (A) pairs with Thymine (T).

Allele

A different version of a gene, inherited through sexual reproduction, with one allele coming from each parent.

Genotype

The genetic makeup of an organism, represented by letters (e.g., BB, Bb, bb).

Phenotype

The observable characteristics of an organism, determined by the genotype (e.g., eye color).

Dominant Allele

An allele that is expressed in the phenotype whenever it is present (represented by a capital letter).

Recessive Allele

An allele that is only expressed in the phenotype when in a homozygous pair (represented by a lower-case letter).

Genetic Profile

A unique pattern of DNA fragments used to compare similarities between DNA samples for criminal cases, paternity tests, or species classification.

Genetic Modification

The process of transferring genetic material from one organism to another to introduce desirable traits.

Sex Chromosomes

The 23rd pair of chromosomes in humans that determine sex: Male (XY) and Female (XX).

Mitosis

A type of cell division used for growth, repair, and replacement of cells, producing two genetically identical daughter cells with the same number of chromosomes as the mother cell.

Meiosis

A type of cell division that occurs only in the formation of sex cells (gametes), producing four new cells each with half the number of chromosomes as the mother cell.

Stem Cells

Undifferentiated cells that can differentiate into any other type of cell, used to replace damaged or diseased tissue.

External Stimuli

Something that the receptor cells detect and send electrical signals

Homeostasis

The maintenance of a constant internal environment, regulated by hormones and the nervous system.

Hormones

Chemical messengers that travel in the blood from a gland to the target organ.

Negative Feedback

A regulatory mechanism where any change from optimal internal conditions results in the body compensating to restore balance.

Diabetes

A condition where a person is unable to control their own blood glucose levels

Phototropism

A growth response in a plant to a one directional stimuli

Vertebrates

animals that have a backbone

Invertebrates

animals that do not have a backbone

Competition

organisms compete for survival

Biodiversity

a measure of the variety of different species and the numbers of each of those species in a particular area

Biological Control

the use of one organism to control the population size of another species by eating it

Predator

an animal that hunts and eats another for food

Prey

an animal that is eaten by a predator

Pest

an organism that eats a crop plant

Native Species

An organism that lives in a country

Alien Species

An organism introduced into a country in which it does not normally live

Invasive Species

An alien organism that has had a negative effect on the native species