Conservation biology exam 2

What is the morphological definition of a species?

Focuses on the morphology of an organism
– Morphology can refer to body size, shape, and/or other structural
features
– Can be applied to both sexually and asexually reproducing individuals
– Challenge: relies on subjective criteria; biologists may disagree on
traits that distinguish a species.

What is the biological definition of species?

States that a species is a group of
populations whose members have the
potential to interbreed in nature and
produce viable, fertile offspring; they
do not breed successfully with other
populations.
– Cannot be applied to organisms that
are completely asexual

Is light required for life?

No because of hydrothermal vents had evolved a specialized organ called a trophosome that houses symbiotic bacteria that provide food to their host. Those symbiotic bacteria were found to be chemosynthetic, able to use a novel process to convert inorganic carbon (CO2) from seawater into organic carbon ([CH2O]n) by using energy produced not by sunlight, but by the oxidation of hydrogen sulfide (H2S) collected from the vents:
6CO2+12H2S(energy)→[CH2O]n+6H2O+12S

What is the list of environment rated from levels of highest to lowest levels of species diversity?

Tropics, Oceans (coral reefs, deep sea), large tropical lakes, temperate forests and shrublands 

What is species richness and what factors affect it?

The number of difference species

1) larger habitat size
2) variation in climate and environment Fig. 3.3
3) variation in topography
4) older geologically
- In North America, large-scale patterns of species richness are highly correlated for amphibians, birds, butterflies, mammals, reptiles, land snails, vascular plants, and tiger beetles. Similar pattern in regions of South America for birds, amphibians, plants, and mammals.

Why do so many species exist in the tropics?

1) large geographic area compared to temperate areas
2) stability -less glaciation with warmer temperatures and higher humidity
3) Warm temperatures and high humidity provide favorable conditions for many species like the many plant species and associated insects specialized to plant parts
4) greater pressure from parasites that prevent a single species from dominating communities. Numerous species at low densities
5) more solar energy and a higher rate of productivity. Greater biomass can support a wide range of species.

How many species exist worldwide?

1.5 million species described worldwide with estimates of 5-10 million total

What is evolution? And what is the difference between micro and macro evolution?

Evolution is the change in the frequency of
genetically determined characteristics within a
population over time.
 Microevolution involves changes in allele
frequencies between populations of the same
species.
 Macroevolution involves major genetic changes that occur over long periods of time that generate new species.
 The mechanisms of micro- and macroevolution are the same.

What assumptions are required for the theory of natural selection?

All organisms produce more offspring than can
survive.
 No two organisms are exactly alike.
 Among organisms, there is a constant struggle for
survival.
 Individuals that possess favorable characteristics for
their environment have a higher rate of survival and
produce more offspring.
 Favorable characteristics become more common in
the species.
 Unfavorable characteristics are lost over time.

What is the role of natural selection in evolution?

Natural selection will select for individuals with
certain alleles.
 When allele frequencies change over time, evolution has occurred.
 Natural selection works on individuals, but only populations evolve.
 Three factors work together to determine how a population changes over time.
 Environmental factors that affect individuals
 Sexual reproduction among the individuals
 Genetic diversity within the gene pool

What is genetic drift and provide an example of it?

Genetic drift involves a significant
change in allele frequency that is not a
result of natural selection.
– Results from chance events
– More likely to impact small
populations

Ex. In a population of 100 plants, 10
of them have red spots on their
leaves.
• If these 10 are randomly
trampled by an animal or are
killed by a late frost
• The red spot allele would be lost,
but not due to natural selection.

What is the bottleneck effect?

A type of genetic drift where the population is extremely reduced. This has an effect on the population’s genetic diversity. Examples include natural disasters and overhunting

What is the founder effect?

A type of genetic drift where a subset of the population colonizes a new location and forms a new colony. If this subset is not representative of the original diversity of the population, it creates a founder effect that can reduce diversity.

What is gene flow?

The movement of a gene
– From one generation to
another
– From one population to
another when animals
migrate
• Both types of gene flow
usually occur together.

What is a niche?

An organism’s niche is its specific functional role
in the community.
– Involves the organisms impact on the biotic
and abiotic elements of the community
– Also involves how the abiotic and biotic
elements in a community impact that
organism

What is niche partitioning? And give and example

The process where species reduce competition by dividing limited recourses into different categories or dimensions allowing them to coexist in the same ecosystem. 

An example of niche partitioning among warblers that search for insects and nest in
different parts of the same tree species. Niche partitioning reduces competition for food and
reproductive sites, allowing the species to coexist.