BIS 2B Final -- UC Davis

Individual

individual traits determine response to environmental factors

Population

-interacting group of conspecific individuals

-group of individuals of sam type of organisms that interbreed

Species

groups of the same type of organisms and descend from common ancestor

Community

set of co-occurring interacting species

Ecosystem

interacting species and abiotic environment

Evolution

change in genetic composition of population over time

Natural selection

differential survival and/or reproduction of individuals with different trait values

Adaptation

-structural/ physiological/ behavioral traits that enhance organism's chances of survival and reproduction in its environment

-trait evolved to enhance organism's survival and reproduction in an environment

-evolutionary change in genotype that increases performance (i.e. process by natural selection)

Estimate total number N for species

N/K=n/k

Species richness

number of species in given area

Species evenness

degree that species are equally abundant

True Diversity equation

D=(p1^-p1)(p2^-p2). . . . (pn^-pn)

Climate

measure of average pattern of variation in temperature, precipitation, and other meteorological variables in given region over long periods of time

Biomes

world's major communities, classified according to predominant vegetation and characterized by adaptations of

Chapparal

temperate shrub land/woodland with:

-hot/dry summer

-wet/cool/moist winter

-dense vegetation and vulnerable to summer fire

Ferrel cell

driven by 60 degree N (clockwise) wind current

Hadley cell

driven by 30 degree N (counterclockwise) wind current

-cool/dry air descending

Coriolis effect

-pushes floating object away from equator and will appear, relative to the earth, to pick up speed and moves east

-push floating object toward equator and will appear, relative to the earth, to lose speed and moves west

-I.E. deflection of air/water as result of differences in Earth's rotational speed at different latitudes

Rain shadow

-North/ South mountain ranges, so precipitation has rising air cooling/condensing while dry air cools/sinks (to desert in valley)

Intertropical Convergence Zone (ICZ)

-two Hadley cells working

-moves North in summer

-moves South in winter

Endemic

occurs in one particular location and nowhere else on Earth

Dispersal patterns

1. regular (uniform) dispersion

2. random dispersion

3.clumped dispersion

Motile

moves from place to place

i.e. animals

Sessile

stays in one place

i.e. still animals

Mycorrhizae

association of fungi with plant roots (>90% terrestrial plants)

-mutualism between plant and mycorrhizae (mycorrhizae not good when high water/nutrients => becomes parasitic)

Cost-benefit Approach

assumes limited time/ energy and used to investigate relationships between behavior, environment, and fitness

Principle of Allocation

all life functions cannot be simultaneously maximized

Trade-off

relationship between benefits of a trait in one context and its costs in another context

Gross Photosynthesis

-changes in O2 in light= photosynthesis-respiration

-changes in O2 in dark= -respiration

-(light change in O2)-(dark change in O2)

Liebig's Law of the Minimum

production only occurs at rate permitted by most limiting factor e.g. sunlight or water or nutrients

Root to Shoot ratio

ratio of below ground to above ground biomass

-Tundra has largest root to shoot ratio

-Tropical forest has lowest root to shoot ratio

Acclimation

change in phenotype within individual's lifetime to increase performance (is often reversible)

C4 and C3 plants

-C4 plants more specialized, but transport of C4 acid to bundle sheath cells is costly

-C3 benefiting from climate change (increases of CO2 and temperature)

Fundamental niche

set of environment conditions that individuals of a species can grow and produce

Strength/ Size Proportions

M^1/3 aproximately = L

Danger index (for surface area/size)

1/L

Metabolic rate

amount of energy expended daily at rest

-metabolic rate/ body mass increase with each other (slope =3/4 for these i.e. 3/4 power rule)

2/3rd law

strength scaling with size

Isometric scaling

all dimensions increase the same amount as the size of the organism changes

Allometric scaling

disproportionate growth of a part or parts of an organism as the size of the organism changes

Density

number of individuals in an area of quadrat

-equation is N/M= n/m

M-captured

N-estimated population size

n-recaptured

m-marked

Population Density and Average Body Size

-decrease

-slope is -3/4

Per-Capita Growth rate

r= b-d

Exponential Growth

N(t)= N0e^rt

-continues to increase

Logistic Growth

-populations may initially grow rapidly when the populations small

-then density-dependent birth/death rates cause r to decline towards 0

-pattern of population growth

Density-dependent

Ex. fire, fecundity, mortality, growth, etc.

-factors include limiting resources, predators, and pathogens

Density-independent

Ex. hurricanes, flash floods, etc.

Allee effect

some populations grow better, with some limit, when population densities are higher rather than lower

Type II Survivorship Curves

probability of surviving to next year is independent of age

-life expectancy is independent of age

Type III Survivorship Curves

high juvenile mortality but low adult mortality

-life expectancy gets better with age

Type I Survivorship Curves

low juvenile mortality but high adult mortality

-life expectancy get worse with age

Life Expectancy at Birth

lx all added together i.e. (l1+l2+l3+. . .+lx)

Life Expectancy at a Certain Age

(l1+l2+l3+. . .+lx)/ lx (lx with x being the age Ex. age 3 = l3)

R0

average number of offspring produced by individual in its lifetime

R0= l1m1+l2m2+l3m3+. . .+lxmx

R0 >1 population increasing

R0 <1 population decreasing

Developing Countries Demographic Transition

stage 2- rapid growth

stage 3- slow growth

stage 4- zero growth

stage 5(?)- negative growth

Toy Model

-population of N individuals where each individual produces 2 offspring then dies

-Each offspring survives to next year with probability of 0.5

Delayed Density-dependence

per capita growth rates depend on past densities

Vestigial structures

Ex. hind limbs in whales OR tailbones in humans

Darwin inferences

1. struggle for existence

2. natural selection

3. adaptation (evolved by natural selection)

evolutionary response (R)

-change in trait mean across generations

R= Trait mean(offspring)- Trait mean (parents prior to selection)

R=h^2S

h^2- heritability

S- selection differential

1. find S or/and h^2

2. plug into equation

3.get R; R never > S and h^2 never >1 or <0 (h^2 as 0 means no R)

Phenotype plasticity

expression of different phenotypes by the same genotype in different environments

-specific Ex. acclimation (improves performance in an environment)

Directional Selection

favors individuals with high/low trait values

-causes change in population trait mean (usually reduces variance)

-acts on individual phenotypes to change population trait mean (and frequency of alleles controlling that trait)

Stabilizing Selection

favors intermediate trait values, decreasing variance

-reduces variance but doesn't change trait mean

Ex. human birth rate

Disruptive Selection

favors extreme trait values, increasing variance

-can lead to bimodal distribution

Sexual selection

selection for traits that enhance reproductive success

-competition among members of same sex

-mate choice by opposite sex

altruist

increase fitness of other individuals at expense of its own fitness

Coefficient of Relationship

(benefit to relatives) x (coefficient of relationship) > (cost to performer)

Genetic Drift

random changes in allele frequencies from one generation to the next generation

-may produce large change in allele frequencies over time

-increasing drift in small populations and can cause loss of allelic diversity and evolutionary change as population size decreases

Population Bottleneck

situation where normally large populations may pass through environmental events that only a small number of individuals survive

Founder effects

resulting change in genetic variation

-small population size unlikely to possess all alleles found in gene pool of its source population

Semelparity

only reproduces once in lifetime

Iteroparity

reproduces more than once in lifetime

r-strategists

species with life history strategies allowing for high population growth rates

-life is uncertain

K-strategists

species with life history strategies allowing them to persist at or near carrying capacity (K) of their environment

-adapted to predicted conditions

Law of Segregation

-when individual produces gametes

-then two copies of the gene segregate and gametes only receive one copy

-Punett Square

Locus (loci)

physical location of gene on chromosome

Multiplication Rule

p1(event 1) x p2(event 2)

Addition Rule

probability of event occurring in two different ways is the sum of individual probabilities

Law of Independent Assortment

-alleles of different genes assort independently during gamete formation

-dihybrid cross (#/16)

Closeness of Loci on Chromosome

-parental gametes more frequent

-probability of recombination of loci that are closer is less likely

3 loci ====> 1. find parental gametes (most common)

2. find double crossovers (least common)

3. allele in middle "switched"

Pleiotropy

allelic variation at one locus affects multiple traits

Ex. pigmentation/hearing in cats

Antagonistic Pleiotropy

occurs when one allele has both positive and negative effects

Ex. Margan's syndrome OR cystic fibrosis

-fitness trade-off across environment

Epistasis

-phenotypic effect of allele at one locus depends upon genotype of allele at another locus

-two genes interacting in developmental or biosynthetic pathway

Ex. labardor fur OR chicken combs

Genotype x Environment Interaction

-phenotypic effect of allele or genotype depends on environment (fitness trade-off)

-geological variation in selection can maintain variation in a species

Genotypic Frequencies

f(rr)= q^2

f(RR)= p^2

f(Rr)= 2pq

Allelic Frequencies

p= f(RR)+1/2f(Rr)

q=f(rr)+1/2f(Rr)

p+q=1 OR 1-p=q ***always adds to 1!***

Prout Square

use allelic frequencies to get genotypic frequencies for a population

Hardy-Weinberg Equilibrium Conditions

1. no new mutations

2. large (infinite) population

3. random mating

4. no gene flow from other population

5. no natural selection

Disassortative Mating

between dissimilar genotypes

heterozygote excessive in newborns

Inbreeding Depression

reduced biological fitness arising from mating close relatives that tend to have the same recessive, sometimes deleterious alleles

Gene Flow

migration of individuals and/or gametes (via propagules such as seeds, etc.)

Recombinant Frequencies

proportions calculated by dividing the number of recombinant progeny by total number of offspring

Heterozygote Advantage

H-W in newborns; increasing heterozygotes with age

heterozygotes have higher fitness

-disease resistance

-antagonistic pleiotropy

-metabolic pathways

Disease Resistant (and polymorphisms)

different resistance alleles may confer resistance against different pathogens

-cystic fibrosis/cholera toxin

-Tay-Sachs disease/ TB

-Phenylketonuria/decreased chance of miscarriage from fungal toxin

Ammensalism

one species harmed and one species unaffected (prey vs. predator)

Antagonistic Interactions

one species benefits and other species is harmed

Mutualism

both species benefit from interaction

Commensalism

one species benefits and other is unaffected

Intraspecific Competition

competition between same species members

-self-thinning in plants

-Scaling law M= N^-3/2 (N decrease/M increase M =>biomass)