Biology Midterm 2 Flashcards
Water relations
How organisms maintain water balance
Water potential
Water’s potential energy or its ability to do work
Evapotranspiration
Moves water up from the soil into the crown of the tree
Ψ humidity
Water vapour pressure
Ψmatric
Matric pressure
Water use efficiency
Biomass of plant tissue produced per gram of water used
Wi
Internal water
Regulating internal water
Aquatic organisms regulate internal water, by balancing water gain against water loss
Trophic (feeding) biology
Grouping organisms by the means by which organisms obtain energy
Autotrophs
(self-feeders) use inorganic sources of both carbon and energy
Photosynthetic autotrophs
Use CO2as a source of carbon and solar radiation in the form of light as a source of energy (plants, photosynthetic protists and photosynthetic bacteria)
Chemosynthetic autotrophs
Use inorganic molecules as a source of carbon and energy
Heterotrophs
Organisms that use organic molecules as a source of carbon and as a source of energy (bacteria, fungi, protists, animals, parasitic plants)
Photoheterotrophs
Use light energy to produce ATP
Prokaryotes
Have cells with no membrane-bound nucleus or organelles, include both bacteria and the archaea
Most trophically diverse organisms in the biosphere
Archaea
Are chemically and genetically more similar to eukaryotes than to bacteria, but are distinguished from bacteria on the basis of structural, physiological, and other biological features
Protists
Either photosynthetic or heterotrophic (single celled)
Photons
(particles of light) bear a finite quantity of energy
Longer wavelengths
Carry less energy than shorter wavelengths, like visible and ultraviolet light
Photosynthetically Active Radiation (PAR)
Visible light is better referred to as photosynthetically active radiation(PAR) and contains wavelengths of solar radiation between about 400 and 700 nm
Photon flux density (PFD)
Number of photons striking a square metre surface each second, used to measure PAR
C3 photosynthesis
“regular photosynthesis” In the photosynthetic pathway, the CO2 first combines with a five-carbon compound. The product of this initial reaction, which is catalyzed by the enzyme RUBISCO, is two molecules, each a three-carbon acid
C4 photosynthesist
Carbon fixation and the light-dependent reactions of photosynthesis occur in separate cells.
Photorespiration
RuBP is partly broken down in this process and a CO2 molecule is released from the plant
CAM (crassulacean acid metabolism) photosynthesis
Largely limited to succulent plants in arid and semiarid
environments.
CAM plants fix carbon by combining CO2with PEP to form four-carbon acids
RUBISCO
Has low affinity for CO2
Ecological stoichiometry
Concerns the balance of multiple chemical elements in
ecological interactions
Detritivores
Feeds on nonliving organic matter
Herbivores
Eats living plants
Carnivores
Mainly eat living animals
Nitrogen use efficiency (NUE)
How much plants can grow per unit of N with strong selection on plants to increase `NEU
Omnivores
Gain energy from, and regularly consume, both plant and animal matter
Mixotrophs
Species able to gain energy both from photosynthesis and from consuming organic or inorganic compounds (e.g. some algae, bacteria and protist species)
Optimal foraging theory
If energy supplies are limited, organisms cannot simultaneously maximize all of life’s functions. There will be a trade-off of time allocation for most organisms; compromises between competing demands
Inclusive fitness
Fitness is determined by individual survival and reproduction plus the survival and reproduction of individuals with whom the individual shares genes
Kin selection
Under some conditions, individuals can increase their inclusive fitness by helping increase the survival and reproduction of genetic relatives that are not offspring
Altruistic act
An act that benefits the recipient but harms the donor, which should not be common in nature, yet, as an example, some red squirrels have been known to adopt the offspring of related squirrels
Group selection
Argues that individuals may act counter to their own personal interests for betterment of the group
Multilevel selection
Evidence has accumulated demonstrating group selection can occur in some special circumstances. It has been rebranded under the term “multilevel selection”
Coefficient of relationship
Can be determined for any two individuals. It will be 25% between grandparent and grandchild, 12.5% between great-grandparent and great-grandchild, 50% between full siblings, and 25% between half-siblings. There is a reduction of 50% in the coefficient in relationship for every additional connection between any two related individuals
Reciprocal altruism
Individuals do not have to be related to each other for altruism to be evolutionarily stable. This model is based upon recognition and experience and is also called “tit-for-tat.”
Sociality
Group living and cooperation
Eusociality
Includes three major characteristics:
- individuals of more than one generation living together,
- cooperative care of young,
- division of individuals into sterile, or nonreproductive, and reproductive castes
Cooperative breeders
Live in groups, with many adults cooperating during the process of producing and/or rearing offspring. Such cooperation extends to offspring that are not their own (e.g. wolf, some birds, African lion)
Hermaphrodites
Individual is able to perform both male and female reproductive functions
Instantaneous hermaphrodites
Perform male and female function at the same time
Sequential hermaphrodites
Individual changes sex
Mating systems
Social, sexual structure of a population
Social monogamy
One male and one female will share and rear any offspring produced by that female
Genetic monogamy
When genes, not social and behavioral norms, dictate the practice of monogamy
Promiscuity
May have multiple sexual partners
Polygyny
One male mates with multiple females while each female mates (putatively) with just one male (most vertebrates)
Polyandry
One female mates with multiple males while each male mates (putatively) with just one female (species of diverse taxa)
Polygynandry
Groups of multiple males and multiple females mate with each other (rare –some primates)
Secondary sexual characteristics
Characteristics of males or females not directly involved in the process of reproduction (e.g. colours, ornaments)
Sexual selection
Process of sexual selection resulting from differences in reproductive rates among individuals as a result of differences in their mating success
Intrasexual selection
Individuals of one sex compete among themselves for mates
Intersexual selection
Members of one sex consistently choose mates from among members of the opposite sex on the basis of some particular trait
Niche
For each species there will be a limited set of conditions
suitable for growth and reproduction
Principle of allometric scaling, or (allometry)
Study of scaling between body size and variousbiological functions, including shape, anatomy, physiology and behaviour
Fecundity
Number of offspring produced by an organism
Ruderals
Plants that live in highly disturbed habitats and may depend on disturbance to persist in the face of potential competition from other plants
Disturbance
Any mechanisms or processes that limit plants by destroying plant biomass
Realized niche
Refers to more restricted conditions of an organism’s niche
Fundamental niche
Represents the maximal niche size of an organism, while the realized niche will be smaller
Phenology
Study of the timing of events in an organism’s life (e.g. when leaves flush out, when offspring are born, when hibernation begins)
Population
Group of potentially interbreeding individuals of
a single species inhabiting a specific area
Population density
Can be absolute density or ecological density
Absolute density
Is what most scientists refer to when they simply say “density”; number of individuals of a population per unit area
Ecological density
Incorporates the concept of the niche, in that not all of the conditions found within a given area will contain the niche requirements of a particular species. The ecological density would be the number of individuals per unit of suitable habitat
Immigration
Movement into a population
Emigration
Movement out of a population
Migration
The seasonal movement of individuals from one location to another
Dispersal
Permanent exodus from one population into another
Expanding populations
Those in the process of increasing their geographic range
Metapopulation
Group of subpopulations living in patches connected by exchange of individuals
Random distribution
Individuals within a population have an equal chance of living anywhere within an area
Regular distribution
Individuals are uniformly spaced
Clumped distribution
Individuals have a much higher probability of being found in some areas than in others
