behavioural adaptations adaptations associated
with the ways in which species respond to their
environment (e.g., migration, foraging behaviour).
(12.1)
beta-oxidation the removal of acetate units from
fatty acids. (3.2)
biodiversity the variety of living organisms that
inhabit Earth. (15.3)
biogeochemical cycle the route that chemical
nutrients take through all biotic and abiotic
components of an ecosystem. (13.4)
biogeography the study of the geographical
distribution of species. (10.2)
biological barriers factors that keep species
reproductively isolated even when they exist in
the same region. (12.2)
biological species population that is reproductively
compatible. Members of the population can
interbreed and produce viable, fertile offspring.
(12.2)
biomass amount of vegetation added to an
ecosystem per area per year (g/m^2 a). (13.3)
biomass pyramid type of graphical representation
showing the pattern of mass changes through a
trophic structure. (13.3)
biomes identifiable ecosystems found in specific
regions on Earth that have particular
combinations of biotic and abiotic factors. (13.1)
bioremediation use of living cells to perform
environmental clean-up tasks, such as cleaning
up PCBs using bacteria that naturally contain
genes that degrade PCBs into harmless
compounds. (9.3)
biosphere all ecosystems and their interactions on
Earth. (13.1)
biotic describes the components of an organism’s
environment that include living things with
which the organism interacts, such as predators,
prey, symbionts, and competition. (13.1)
biotic potential the highest possible per capita
growth rate possible for a given population.
(10.2, 14.2)
births the number of individuals born during a
given time period; in population dynamics, a
factor that increases the population. (14.2)
bottleneck effect effect that occurs when a
population is greatly reduced by events such
as natural disaster or overhunting, resulting in
certain alleles being overrepresented and other
alleles being underrepresented or absent in the
population, due to chance. The effect leads to a
genetic drift and decreased genetic variation in
the population. (11.3)
Bowman’s capsule the receiving end of a renal
tubule at which water and small solutes from
the blood enter the proximal tubule from the
glomerulus. (4.2)
buffers chemicals or combinations of chemicals that
resist changes in pH by taking up extra hydrogen
ions or hydroxide ions in solution. (1.3, 4.2)calcitonin a hormone produced in the thyroid
gland, which regulates calcium levels in the
blood. Works in conjunction with the parathyroid
hormone. (6.1)
Calvin cycle process in which green plants fix
carbon from atomospheric CO 2 to produce
carbohydrates. This process is the second of two
major stages of photosynthesis (following the
photo reactions). (3.3)
carbon fixation the initial incorporation of carbon
from atmospheric CO 2 by green plants into
organic molecules. (3.3)
carcinogenic describes a factor, such as a chemical
mutagen, that is associated with one or more
forms of cancer. (9.1)
cardiac centre part of the medulla oblongata that
controls heart rate and the force of the heart’s
contraction. (5.1)
cardiolipin the inner membrane of the
mitochondrion. (3.2)
carrier proteins proteins in a cell membrane that
are able to move and change shape to assist large
molecules to enter a cell by passive transport.
(1.3)
carrying capacity (K) the maximum population size
that can be sustained in a given environment
over a long period of time. (14.2)
catalysis the acceleration of a chemical reaction by
a substance that is regenerated, unchanged, at the
end of a chemical reaction. (2.2)
catalytic cycle process in which substrates form an
enzyme-substrate complex and are then are
released from the complex as a product or
products, freeing the enzyme for further
reactions. (2.2)
cataract cloudy or opaque areas on the lens of the
eye that increase in size over time and eventually
cause blindness. (5.3)
catastrophism the idea that catastrophes such as
floods, diseases, or droughts periodically
destroyed species living in a particular region,
allowing species from neighbouring regions to
repopulate the area. (10.2)
cation positively charged ion (has more protons
than electrons). (1.2)
cell body the main part of a neuron, containing the
nucleus and other organelles. (5.1)C
Glossary • MHR 571