Final - Ecology (Salas )

Final - Ecology (Salas )

Ecology

The scientific study of the abundance and
distribution of organisms in relation to other organisms
and environmental conditions

The Hierarchy of Organization in Ecological
Systems

Individual

A living being; the most fundamental unit of
ecology.

species

A group of organisms that interbreed with
each other and produce fertile offspring.

population

Individuals of the same species living in a
particular area.

community

All populations of species living together in
a particular area.

ecosystem

One or more communities of living
organisms interacting with their nonliving physical and
chemical environments

biosphere

All the ecosystems on Earth.

individual approach

Emphasizes the way in which an
individual’s morphology, physiology, and behavior enable it
to survive in its environment.

population approach

Emphasizes variation over time
and space in the number, the density, and the composition
of individuals.

community approach

Emphasizes the diversity and
relative abundances of different kinds of organisms living
together in the same place.

ecosystem approach

Emphasizes the storage and
transfer of energy and matter, including the various
chemical elements essential to life.

biosphere approach

Concerned with the largest
scale, including movements of air and water—and the
energy and chemical elements they contain—over Earth’s
surface

law of conservation of matter

Matter cannot be created or destroyed; it can only change form.

law of conservation of energy aka first law of thermodynamics

Energy cannot be
created or destroyed; it can only change form

dynamic steady state

When the gains and losses of
ecological systems are in balance.

producers

An organism that uses photosynthesis to
convert solar energy into organic compounds or uses
chemosynthesis to convert chemical energy into organic
compounds.

Also known as Autotroph.

consumers

An organism that obtains its energy from
other organisms.

Also known as Heterotroph.

mixotroph

An organism that obtains its energy from
more than one source.

predator

An organism that kills and partially or entirely
consumes another individual.

interaction table

habitat

The place, or physical setting, in which an
organism lives.

niche

a specialized, focused area of interest, market, or role, typically aimed at a small, select group rather than the general public

the word ecology is derived from the greek oikos, which means

a house

deoxyribonucleic acid (dna)

a molecule composed of two
strands of nucleotides that are wound together into a double
helix.

chromosomes

compact
structures consisting of long
strands of DNA wound around
proteins

alleles

different forms of a particular gene

genes

are regions of DNA that code for particular proteins;
changes in some phenotypes are affected by a single allele
(e.g., blood type)

polygenic

when a single trait
is affected by several genes;
enables phenotypes to span a
range of values in a population
(e.g., human body height).

pleiotropy

when a single gene affects multiple traits.

epistasis

when the expression of one gene is controlled by
another gene

gene pool

collection of alleles from all individuals in a
population

dominant

an allele that masks the expression of the other
allele

recessive

an allele whose
expression is masked by another
allele; most harmful alleles are
recessive

codominant

when two alleles both
contribute to the phenotype
(e.g., flower color in snapdragons).

heterozygous

when an individual has
two different alleles of a particular gene

homozygous

when an individual has
two identical alleles of a particular gene

random assortment

The combination of alleles in each
gamete could be any combination of those possessed by
the diploid parent.

mutation

A random change in the sequence of
nucleotides in regions of DNA that either comprise a gene
or control the expression of a gene

recombination

The reshuffling of genes that can occur as
DNA is copied during meiosis and chromosomes exchange
genetic material

genetic drift

a process that occurs when genetic variation is lost due to
random variation in mating, mortality, fecundity, and inheritance

bottleneck effect

a reduction of genetic diversity in a population due to a
large reduction in population size (e.g., from loss of food)

founder effect

when a small number of individuals leave a large
population to colonize a new area and bring with them only a small amount of genetic variation.

selection

the process by which certain phenotypes are
favored to survive and reproduce over other phenotypes

stabilizing selection

when individuals with intermediate
phenotypes have higher survival and reproductive success
than those with extreme phenotypes

directional selection

when individuals with extreme phenotypes
experience higher fitness than the average population phenotype

disruptive selection

when individuals with either extreme phenotype
experience higher fitness than individuals with an intermediate phenotype

microevolution

the evolution of populations; affected by random
processes and selection

artificial selection

humans

Selection in which humans
decide which individuals will breed; breeding is
done with a preconceived goal for the traits in the
population

(e.g., dogs, wild mustard).

natural selection

ecological process;
individuals interact with their environment, and
traits that lead to greater fitness in an
environment are passed on

industrial melanism

a phenomenon in which industrial activities cause
habitats to become darker due to pollution; individuals possessing darker
phenotypes are favored by selection

macroevolution

evolution at higher levels of organization
including species, genera, families, orders, and phyla

speciation

the evolution of new species

phylogenetic trees

hypothesized patterns of relatedness
among different groups such as populations, species, or
genera; depict which groups evolved from other groups

allopatric speciation

the evolution of
new species through the process of
geographic isolation

sympatric speciation

he evolution of new species without
geographic isolation.

life history

the schedule of an organism’s growth, development,
reproduction, and survival; represents an allocation of limited time and
resources to achieve maximum reproductive success.

fecundity

the number of offspring produced by an organism per
reproductive episode

parity

he number of reproductive
episodes an organism experiences.

parental investment

the time and
energy given to an offspring by its
parents

longevity (life expectancy)

the
life span of an organism.

‘‘ slow ‘‘ life history

Long time to sexual maturity
Long life spans
Low numbers of offspring
High parental investment

Examples: elephants, oak
trees

‘‘ fast’’ life history

Short time to sexual maturity
Short life spans
High numbers of offspring
Little parental investment

Examples: fruit flies, weeds

principle of allocation

when resources are devoted to one body
structure, physiological function, or behavior, they cannot be allotted to
another

offspring number vs size

Most organisms face a trade-off between the number of offspring they can produce and the size of those offspring

offspring number vs parental care

As the number of offspring increases, the amount of parental care per
offspring will decrease and reduce chances of offspring survival

parental care vs parental survival

Having more offspring can stimulate parents to hunt harder for food to feed their offspring. This additional effort can affect the parent’s fitness

growth rate vs fitness

Allocation of energy to increased fecundity during one year occurs at the
cost of further growth that year

determinate growth

a growth pattern in which an individual does not
grow any more once it initiates reproduction; occurs in many species of
birds and mammals

indeterminate growth

a growth pattern in which an individual continues
to grow after it initiates reproduction; occurs in many species of plants,
invertebrates, fishes, reptiles, and amphibians

Semelparity

when organisms reproduce only once during
their life; relatively rare in vertebrates, but common in insects
and plants.

bamboo

agaves

iteroparity

when organisms reproduce multiple times during
their life; common among birds, reptiles, mammals, and
amphibians.

yuccas

cicadas

spend the first part of their life underground where they obtain
nutrients from xylem tissue of plant roots

senescence

a gradual decrease in fecundity and an increase
in the probability of mortality

photoperiod

the amount of light that occurs each day

sexual reproduction

a reproduction mechanism in which progeny
inherit DNA from two parents

asexual reproduction

a reproduction mechanism in which progeny
inherit DNA from a single parent.

gonads

the primary sexual organs in animals.

vegetative reproduction

a form of asexual reproduction in which an
individual is produced from the nonsexual tissues of a parent

clones

individuals that descend
asexually from the same parent
and bear the same genotype

binary fission

reproduction
through duplication of genes
followed by division of the cell
into two identical cells.

cost of meiosis

the 50%
reduction in the number of a
parent’s genes passed on to the
next generation via sexual
reproduction versus asexual
production; occurs because
sexual genes are haploid.

purging mutations

Sexually reproducing organisms can lose
deleterious mutations during meiosis.

copying with environmental variation

offspring are likely to
encounter different environmental conditions than their parents did

copying with parasites and pathogens

pathogens have much shorter
generation times and larger population sizes than the host species
they infect

red queen hypothesis

sexual selection allows hosts to evolve at a
rate that counters the rapid evolution of parasites.

perfect flower

flowers that contain both male and female flowers

simultaneous hermaphrodites

individuals that possess male and
female reproductive functions at the same time

sequential hermaphrodites

individuals that possess male or female
reproductive function and then switch to the other

monoecious

plants that have separate male and female flowers on
the same individual

dioecious

plants that contain either only male flowers or only
female flowers on a single individual.

Selfing, or self-pollination vs outcrossing

occurs when an
individual’s male gametes fertilize its own female gametes.

Since this poses a cost due to inbreeding depression, selection
should favor individuals that can breed with other individuals (i.e.,
outcrossing) when possible.

genetic sex determination

In organisms with separate sexes, the sex ratio of male to female
offspring is often one to one.

Sex is often determined by inheritance of sex-specific chromosomes
(e.g., human females have two X chromosomes (XX); males are XY

environmental sex determination

a process in which sex is
determined largely by the environment; this is a type of phenotypic
plasticity, where the phenotype is sex.

temperature - dependent sex determination

occurs when the sex of an individual is determined by the temperature at which eggs develop

offspring sex ratio

Females can influence the sex ratios of their offspring.

frequency - dependent selection

when the rarer phenotype in a
population is favored by natural selection

high skewed sex ratio aka local mate competition

which is
when competition for mates occurs in a very limited area, and only a
few males are required to fertilize all of the females

mating systems

the number of mates each individual has and the
permanence of the relationship with those mates.

promiscuity

males mate with multiple females
and females mate with multiple males and do
not create lasting social bonds; common among
animals and outcrossing plants