Module 3: Biological Diversity

abiotic factors

Nonliving components of environment.

biotic factors

living parts of an ecosystem

selective pressure

environmental conditions that select for (favour) certain characteristics of individuals

positive selection pressure

A factor that increases the likelihood of a particular species or variations within a species surviving to reproduce.

negative selection pressure

A factor that decreases the likelihood of a particular species or variations within a species surviving to reproduce.

Tolerance range

The abiotic conditions within which a species can survive

Optimum range

The narrow range within the tolerance range, at which the organism functions best

trophic level

Each step in a food chain or food web

Producer

An organism that can make its own food.

Consumer

An organism that obtains energy by feeding on other organisms

primary consumer

An organism that eats producers

secondary consumer

An organism that eats primary consumers

tertiary consumer

An organism that eats secondary consumers

food chain

A series of steps in which organisms transfer energy by eating and being eaten

food web

A community of organisms where there are several interrelated food chains

Population

A group of individuals that belong to the same species and live in the same area

Community

All the different populations that live together in an area

Ecosystem

A biological community of interacting organisms and their physical environment.

Biome

A group of ecosystems that share similar climates and typical organisms

Distribution

areas of the world in which a species lives

Abundance

How many individuals of that species live in a particular area

Capture-mark-recapture

an ecological surveying technique used to measure animal populations, in which individual animals are captured, marked and released; after a time, the population is re-sampled and the number of marked animals caught gives an indication of population size.

Quadrat sampling

square or rectangular plot of land, a quadrat, marked off at random to isolate a sample and determine the percentage of vegetation or animals occurring within the marked area.

Transect

A straight line across an expanse of ground along which ecological measurements are taken, continuously or at regular intervals.

Percentage cover method

Technique used to estimate the percentage of an area covered by a particular species

Sampling Techniques

Capture-marl-recapture, quadrats, transects, percentage cover

Adaptation

A characteristic that improves an individual's ability to survive and reproduce in a particular environment.

Behavioural adaptation

Actions of individuals or groups which increase the chances of survival and reproduction.

physiological adaptation

a physical or chemical event that occurs within the body of an organism and enables survival

structural adaptation

An inherited physical characteristic that helps an organism survive in its environment.

Xerophytes

plants adapted to arid climates

Mesophytes

a plant needing only a moderate amount of water.

Hydrophytes

plants with adaptations that enable them to survive in very wet habitats or submerged or at the surface of water.

Adaptations of xerophytes to conserve water

Rolled leaves, thick wacy cuticle, sunken stomata, stomatal hairs, vertical orientation of leaves, small leaves, light coloured leaves

evaporative cooling

Reduction in temperature resulting from the evaporation of a liquid, which removes heat energy from the surface from which evaporation takes place

Examples of structural adaptations in animals

Thick fur and blubber to insulate against cold

Bright feathers to attract mates

Large ears to increase heat loss/small ears to reduce heat loss

Webbed feet and flippers for swimming

Spines for protection

Examples of physiological adaptations of animals

Producing poison or venom

Examples of behavioural adaptations of plants

Thigmonasty, tropism

Examples of behavioral adaptations of animals

Seeking or leaving shade or shelter, huddling, panting or licking, mouth gaping

Examples of physiological adaptations of plants

Shedding leaves overloaded with salt.

Excreting salt from salt glands.

Pumping salt out of roots

Increasing water uptake to dilute salt

natural selection

A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits.

Evolution

Change in a kind of organism over time; process by which modern organisms have descended from ancient organisms.

Modern day example of evolution

Antibiotic resistance

Speciation

Formation of new species

allopatric speciation

The formation of new species in populations that are geographically isolated from one another.

Microevolution

Changes in alleles, populations or species over short periods of evolutionary time.

Macroevolution

Evolutionary change above the species level. Happens over thousands to millions of generations and produces many different species, families, orders and phylum.

Coevolution

Process by which two species evolve in response to changes in each other

divergent evolution

when two or more species sharing a common ancestor become more different over time

convergent evolution

Process by which unrelated organisms independently evolve similarities when adapting to similar environments

punctuated equilibrium

Pattern of evolution in which long stable periods are interrupted by brief periods of more rapid change

Charles Darwin theory of evolution by natural selection

The theory that through natural selection evolution occurs - (change in living organisms overtime)- different variation in species- some will be favourable- these ones will survive and reproduceSome will have a common ancestor but change according to the selective pressureswhile some may have further away common ancestors but evolve to be similar due to similar selective pressures

Biochemical Evidence for Evolution

looking at DNA or molecular structures for differences and similarities to present day organisms

DNA hybridisation

Comparison of nucleotides base sequences of two or more species to determine their evolutionary relatedness.

Amino acid sequencing

Comparison of the sequences of amino acids within a protein common to two or more species to determine their evolutionary relatedness.

Comparative anatomy

The comparison of body structures and how they vary among species

Palaeontology

the study of fossils

comparative embryology

the study of the similarities and differences in the embryos of different species

Biogeography evidence for evolution

group of similar species tend to be near each other

i.e finches on island and on mainland

groups that have evolved since Pangea broke up have unique characteristics to that region of Earth