Biology Grade 12 Unit 3

Adaption

A feature of an organism that enhances its ability to survive and reproduce in a particular environment

Ecosystem

A biological community of interacting organisms and their physical environment

Biotic

Living components of an environment

Biodiversity

The range of living organisms within an environment.

Abiotic

the non-living physical factors that affect the organism’s ability to survive

Hierarchical

relating to the graded organisation of grouping from general to ver specific sub-groups

Classification

grouping of organisms based on similarities in morphology, anatomy and biochemistry

Asexual Reproduction

the production of genetically identical offspring from a single parent

Sexual reproduction

The production of offspring that has genetic material from two parents

Taxonomy

The science of naming and classifying living things

Taxon

Any group in a biological classification into which related organisms are classified, for example Phylum class etc.

Mutation

Small permanent change in the DNA of an organism

Species

Taxonomic group, allocated two (genus and specific) names; only members of the same species can produce fertile offspring when mating under natural conditions

Genus

Classification category between family and species: first part of the scientific name of an organism

Family

Subdivision of an order in the classification of living things

Order

Subdivision of a class in the classification of living things

Class

One of the groups used in the classification of organism consisting of a number of orders, for example animals in class Mammalia all share specific characteristics

Phylum

Major classification group of the animal kingdom

Division

Major classification group of the plants, fungi and plant-like protists

KIngdom

A subdivision of a domain; group of organisms with very general common features

Domain

Broadest taxonomic group

Binomial nomenclature

method of naming species of organisms with two parts: the generic and specific names, e.g. Eucalyptus crebra

specific name

the descriptive name of the species

extremophiles

organisms that live in extreme environments

reproductive isolation

the inability of different populations or species to successfully interbreed due to behavioural, structural, or physiological features of the organisms

Hybrid

offspring resulting from a cross between parents that are genetically different, for example two closely related species or varieties in species.

apomixis

asexual reproduction

parthenogenesis

reproduction from an ovum without fertilisation in animals

variety

a group that distinctly differs from other varieties within the species, for example a poodle and a Great Dane

subspecies

a rank immediately below a species; a population that is genetically distinguishable from other populations of the same species in a particular geographical region, capable of interbreeding successfully where ranges overlap

race

one group of the population that is genetically different from other groups as a result of having a different range

diagnostic features

any feature used to separate in the classification of organisms

homologous structures

similar structures with slightly different functions that indicate shared ancestry

divergent evolution

evolution that leads to descendants becoming different in form from their common ancestor

analogous structures

structures with a similar function but no structural relationship

convergent evolution

the independent development of similarities between species as a result of having similar ecological roles and selection pressures

vestigial structures

a structure with no apparent function, but which may have had a function in an ancestral species

embryology

growth and development of zygote until birth

geographic distribution

the natural range of the various forms of animals and plants in the different regions and localities of the earth

phylogeny

the evolutionary history of a kind of organism

cladistics

a method of grouping organisms that uses evolutionary lines of descent rather than structural similarities

shared characteristic

a feature that all members of a group have in common

derived characteristic

a feature that sets members of that clad apart from other individuals

cladogram

a branching diagram showing the evolutionary relationships between a number of species

cladogenesis

the making of a clade by means of an ancestor species evolving into two or several new species

plesiomorphy

an ancestral characteristic or trait that is shared by two or more taxa

apomorphy

a specialised trait or characteristic that is unique to a group or species

clade

a group of organisms that is believed to comprise a common ancestor and all of its evolutionary descendants

karyotype

the number of chromosomes in the cell nuclei of an organism or species

molecular analysis

a branch of biochemistry in which the molecular basis of biological activity of molecules such as DNA, RNA and proteins is studied

molecular clock

a technique that uses mutation rate to deduce when two mor more life forms diverged

immunological difference

the degree of difference between two proteins

DNA-hybridisation

a technique that measures the degree of genetic similarity between the DNA sequences of different individuals

Mitochondrial DNA

a double stranded DNA molecule found only in mitochondria’ in most eukaryotes is circular and maternally inherited

dichotomous key

identification key with only two alternatives at each stage

Abiotic

features that include climate, soil and geography

Optimal Range

the level an abiotic factor at which an organism will best survive

physiological stress

the inability of an organism to function at maximum as a result of some factor

tolerance range

the range of a particular abiotic factor within which an organism can survive

Biotic

the living components in the environment

Species diversity

a measure of the number of species found in a community, compared with the number of individuals

monoculture

a system that has very low diversity; in agriculture, it describes the practice of growing a single type of crop

species richness

a measure of the number of species present and the evenness of species in relation to one another

Simpson’s Index (D)

the probability that the two individuals randomly selected from a sample will belong to the same species (or genus or family, etc.)

Simpson’s Diversity Index (SDI)

the probability that two individuals randomly selected from a sample will belong to different species (or groups)

Zonation

the breaking of the biome into habitat zones

stratification

the division of the physical environment into smaller components for sampling

random sampling

a method of selecting a sample from a total array in such a way that every possible sample that could be selected has an equal chance of being selected

foliage cover

an estimate of the area or percentage of a sample site occupied by the natural spread or plant foliage

plot

an area under investigation - generally a subset of a larger area

quadrat

a rectangular or square plot or known dimensions

quadrant

each of four quarters of a circle

transect

a measured length or strip of terrain in an environment along which individual organisms or environmental parameters are measured and recorded

belt transect

an elongated area of known length and width through a particular environment in which specific community parameters are measured and recorded

profile

slope of the terrain, position and height of vegetation types and canopy cover

plan sketch

an aerial view showing position and canopy cover of species

line intercepts

a sampling technique used to estimate relative densities of a species by counting the number of individuals that lie on a straight line cutting through the community

strip census

an estimate of the numbers of a wild animals in an area by counting individuals along a typical strip and assuming a uniform population

Berlese-Tullgren funnel

a device used to extract small animals from a leaf litter

pit-fall trap

a device used to trap small animals that are active on the ground surface

capture-recapture

method of estimating population density of animals are captures, marked and released; their proportion in subsequent trapping allows estimation of population size

Lincoln Index (N)

a method used to estimate the size of closed populations in which random samples of the population are captured, marked and released to mingle with the general population for a period of time before subsequent trapping

Ecology

The study of relationships between organisms and their environment

Environment

the conditions (biotic and abiotic) in which an organism lives

Biosphere

the part of the earth that supports life

Habitat

a specific location, with a particular set of biotic and abiotic conditions; where an organism normally lives

population

number of individuals of a species living in a particular place at a particular kind

Community

all the species that occupy a particular place at a given time

ecosystem

a biological community of interacting organisms and their physical environment

niche

a species role and position in its environment; a species interaction with the biotic and abiotic factors of its environment

abiotic

the non-living physical factors that affect an organism’s ability to ability to survive

Producer

(autotrophic) organism forming the base of all food chains; converts simple organic chemicals into complex organic molecules (food)

consumer

organism that eats another living organism (or part of an organism) for nutrition

heterotroph

an organism that eats other living organisms

herbivore

plant-eating organism

carnivore

meat-eating organism

omnivore

an organism that can utilise a range of nutrients; both herbivorous and carnivorous

detritivore

an organism that feeds on detritus

decomposer

an organism that utilises dead organisms or wate matter for its nutrients, releasing simple inorganic molecules

intraspecific

within a species; between individuals of the same species