Life Sciences 11 Final Exam Vocabulary

Natural selection

The process by which organisms better adapted to their environment tend to survive and produce more offspring.

Artificial selection

The intentional (human) breeding of organisms to produce desirable traits.

Equilibrium

A state of balance - may refer to populations, evolutionary change, etc

Homologous structures

Structures that have originated from a common ancestor but may have different functions.

Adaptive radiation

The diversification of an ancestral species into different forms to occupy different ecological niches.

Convergent evolution

The process by which unrelated species evolve similar traits due to similar environmental pressures.

Divergent evolution

The accumulation of differences between groups which can lead to the formation of new species

Founder effect

The reduced genetic diversity that results when a population is descended from a small population

Bottleneck effect

A sharp reduction in the size of a population due to environmental events or human activities.

Cladogram

A diagram showing the evolutionary relationships among a group of organisms.

Microevolution

Evolutionary change within a species or small group of organisms.

Macroevolution

Evolutionary change that occurs at or above the level of species. - e.g. the formation of mammals

Complimentary base pairing

The specific pairing of nitrogenous bases in DNA: adenine with thymine, and guanine with cytosine.

Guanine

Nitrogenous base - pairs with Cytosine

Adenine

Nitrogenous base - pairs with Thymine

Thymine

Nitrogenous base - pairs with Adenine

Cytosine

Nitrogenous base - pairs with Guanine

DNA

Deoxyribonucleic acid, carries genetic information for the function of organisms

Double helix

The structure of DNA, resembling a twisted ladder.

Sugar phosphate backbone

The structural component of DNA, consisting of alternating sugar and phosphate groups.

Nitrogenous bases

The molecules that form the building blocks of nucleic acids, including adenine, guanine, cytosine, and thymine,

Mutations

Changes in DNA caused by environmental factors or random chance

Evolutionary change

The process by which species accumulate differences over time.

Gene flow

The transfer of genetic material from one population to another.

Gene drift

Changes in the gene pool of a population due to random chance.

Non random mating

Mating between individuals that is not random - sexual reproduction

Speciation

The formation of new and distinct species in the course of evolution. through evolutionary change

Sympatric populations

Populations that live in the same geographic area.

Allopatric populations

Populations that live in different geographic areas.

Pre mating isolation mechanisms

Mechanisms that prevent mating between different species before the actual mating occurs.

Character displacement

The accentuation of distinctive features in regions where similar species co-exist

Post mating isolation mechanisms

Mechanisms that prevent hybrid zygotes from developing into viable, fertile offspring.

Punctuated equilibrium

The theory that evolution occurs in spurts

Gradualism

The theory that evolution occurs slowly and incrementally

Extinction

The complete disappearance of a species from Earth.

Fossil record

The total collection of fossils that have been found throughout the world.

Nucleotides

The building blocks of DNA, consisting of a sugar, a phosphate group, and a nitrogenous base.

Analogy

similarity of function and resemblance of structures that have different origins.

Allele frequency

How common an allele (e.g. blue eyes) is in a population

Inbreeding depression

The reduced biological fitness in a population due to inbreeding.

Common ancestor

An ancestral species from which two or more species have evolved.

Adaptation

A trait that helps an organism survive and reproduce in its environment.

Fitness

The ability of an organism to survive and reproduce in its environment.

Classification

The process of grouping things based on their similarities.

Taxonomy

The science of classifying and naming organisms.

Taxon/taxa

Groups of organisms at any rank in the classification system (e.g. Mammals, reptiles, fungi)

Binomial nomenclature

The system of naming species with two names, the genus name and the species name.

Domain

The highest taxonomic rank of organisms - bacteria, archaea, and eukarya

Kingdom

Second highest taxonomic rank - animalia, plantae, etc

Phylum

A taxonomic rank below kingdom and above class. - porifera, choradata, mollusca

Order

A taxonomic rank below class and above family. - primates, carnivora

Family

A taxonomic rank below order and above genus. - canidae, felidae, ursidae

Class

A taxonomic rank below phylum and above order. - mammalia, reptile

Genus

A taxonomic rank below family and above species. - homo, panthera

Species

The most specific level of taxonomic classification. - homo sapiens, homo erectus

Protista

A kingdom of simple eukaryotic organisms.

Fungi

A kingdom of eukaryotic organisms that includes yeasts, molds, and mushrooms.

Plantae

A kingdom of multicellular photosynthetic organisms.

Animalia

A kingdom of multicellular eukaryotic organisms that are heterotrophic (relies on other organisms for nutrients)

Archaea

One of two prokaryotic domains, the other being Bacteria.

Bacteria

A domain of prokaryotic microorganisms.

Eukaryote

An organism whose cells contain a nucleus.

Prokaryote

An organism whose cells do not have a nucleus.

Biodiversity

The variety of life in the world or in a particular habitat or ecosystem.

Cells

The basic structural and functional units of all living organisms.

Organism

An individual animal, plant, or life form

Population

A group of organisms of the same species that live in the same area.

Ecosystem

A biological community of interacting organisms and their physical environment.

Community

All the populations of different species that live and interact in the same area.

Producer

An organism that produces its own food through photosynthesis or chemosynthesis.

Primary consumer

An organism that feeds on producers.

Secondary consumer

An organism that feeds on primary consumers.

Tertiary consumer

An organism that feeds on secondary consumers. - apex predator

Keystone/apex predator

Predator at the top of the food chain, without natural predators

Decomposers

Organisms that break down dead or decaying organisms.

Omnivore

An organism that eats both plants and animals.

Carnivore

An organism that primarily eats meat.

Herbivore

An organism that primarily eats plants.

Detritivore

An organism that feeds on r decomposing organic material.

Energy pyramids

Diagrams that show the flow of energy through trophic levels in an ecosystem.

Cellular respiration

Process by which oxygen is used to make energy from carbohydrates

Photosynthesis

The process by which organisms use sunlight to produce food, using chloroplasts

Symbiosis

A close ecological relationship between two or more organisms of different species.

Predation

The preying of one animal on others.

Competition

The competition between organisms in which both compete for a shared resource

Commensalism

Organism relationship in which one benefits and the other is neither benefitted or harmed.

Parasitism

A relationship between two organisms where one benefits and the other is harmed.

Mutualism

A relationship between two species in which both benefit.

Niches

The role and position a species has in its environment.

Habitat

The natural home or environment of an organism - ex. Sahara Desert

Logistic growth

Population growth that is controlled by limited resources.

Exponential growth

Population growth that is unrestricted by limiting factors.

Survivorship curves

Graphs showing the proportion/number of individuals surviving to each age for a given species

Cyclic growth

Population growth that rises and falls in a predictable pattern.

Environmental resistance

Factors that limit the growth of a population.

Opportunistic pattern of growth

A pattern of growth where organisms take advantage of favorable conditions to reproduce rapidly.

Equilibrium pattern of growth

A pattern of growth where population size remains relatively constant.

Density dependent factors

Factors that limit a population more as population density increases.

Density independent factors

Factors that limit a population regardless of population density.

Cohort

A group of animals of the same species and is recognized by common characteristics