Ecology Test #2


Terms in this set (...)

Chemosynthetic Autotrophs
refers to autotrophs that use inorganic molecules as a source of carbon and energy. Located along the oceanic rift.
Feed on plants
Feed on animals. Nutrient rich.
Feed on non-living organic matter. Consume food rich in carbon and energy but poor in nitrogen
5 elements of plants, animals, fungi and bacteria
1. Carbon
2. Oxygen
3. Hydrogen
4. Nitrogen
5. Phosphorus
Other essential plant nutrients
1. Potassium
2. Calcium
3. Magnesium
4. Sulfur
5. Chlorine
6. Iron
7. Manganese
8. Boron
9. Zinc
10. Copper
11. Molybdenum
-Substantial nutritional chemistry problems
-Low nitrogen concentration
-Must overcome plant physical and chemical defenses
-Cellulose; lignin; silica
-Digestion reducing compounds
Prey Defenses
-Aposomatic coloring: warning colors
-Mullerian mimicry: comimicry among several species of noxious organisms
-Batesian mimicry: harmless species mimic noxious species
Energy Limitation
-Limits on potential rate of energy intake by plants have been demonstrated by studying response of photosynthetic rate to photon flux density.
-Limits on potential rate of energy intake by animals have been demonstrated by studying relationship between feeding rate and food availability
Holling basic functional responses
1. Feeding rate increases linearly as food density increases - levels off at max. Consumers require little or no search and handling time.
2. Feeding rate rises in proportion to food density. Feeding rate partially limited by search/handling time.
3. Feeding rate increases most rapidly at intermediate densities. (s-shaped)
Population genetics
genetic variation in populations is required for evolutionary change
Henry Weinberg equilibrium model
In a population mating at random in the absence of evolutionary forces, allele frequencies will remain constant.
Conditions Necessary for Henry Weinberg
-Random mating: preferential mating can change the frequency in genotypes
-No mutations: mutations can add or change alleles
-Large population size: increased chance of genetic drift in small populations, which increases the frequency of some alleles and reduces or eliminates the frequency of others, leading to lower genetic variation
-No immigration: immigration can introduce new alleles into a population
-Equitable fitness between all genotypes: if different genotypes survive and reproduce at different rates, then gene and genotype frequencies will change in populations
Natural selection
differential survival and reproduction among phenotypes
Three forms of natural selection
1. Stabilizing selection
2. Directional selection
3. Disruptive selection
Stabilizing selection
Impedes changes in population by favoring average phenotypes. Higher fitness in average phenotypes. Requirement: constant and favorable environment
Directional selection
favors certain extreme phenotypes to increase fitness
Disruptive selection
favors two or more extreme phenotypes over the average phenotype in the population
Phenotypic plasticity
variation among individuals in form and function as a result of environmental influences
Behavioral ecology
relationship between organisms and the environment that are mediated by behavior
cooperative feeding, defense of the social group and restricted reproductive opportunities
1. individuals of more than one generation living together
2. cooperative care of young
3. division of individuals into sterile and reproductive castes
Male-male combat
Occurs when males guard females or resource/territory
Female choice
Selection for secondary sexual characteristic
-physical trait
-courtship display
High cost to male
Parental Investment
-Rearing of offspring
-Nuptial gifts
Kin selection
Selection will favor diverting resources to kin (relatives) under conditions where the benefit to the helper, measured as improved survival and reproduction of the kin, exceeds its cost to the helper -> inclusive fitness
Geographic range-area in which population may be present
Suitable habitat
-Defined by: food availability, shelter, microclimates
-Edges generally poorer quality habitat
-Habitat framentation
Local populations interacting within a large area or region
E=the rate of local extinction
e=the probability of local extinction
P=proportion of patches occupied over the time interval
Source and Sink populations
-Source populations exist in high-quality habitat and exhibit positive growth (r <0)
-Sink populations accept immigrants and may be misleading because they may exist in low-quality habitats (r <0)
Patterns of survival
survival within a population are described using life tables
Cohort life table
identify a larger number of individuals born around the same time (cohort) and keep records of them from birth to death
Static life table
record the age of death of a large number of individuals
Age distribution
proportion of individuals of different ages within a population
Type I survivorship curve
Juvenile survival is high and most mortality occurs among older individuals
Type II survivorship curve
Individuals in a population die at equal rates, regardless of age
Type III survivorship curve
Individuals die at a high rate as juveniles and then at much lower rates later in life
Age structure
Proportion of population in each age class
Geometric growth
Growth in discrete annual pulses
Exponential growth
Continuous population growth
K selection
-Few offspring
-Long gestation
-Long parental care
-Long period until sexual maturity
r selection
-many offspring
-short gestation
-less parental care
-short time until sexual maturity
Intraspecific Competition
between individuals of the same species
Interspecific Competition
between individuals of two or more species
Scramble Competition
growth & reproduction depressed equally across individuals in a population
Contest Competition
some individuals gain adequate resources, others do not