Bio 155- Lecture exam 1

Emergent properties

New, complex functions result from interactions among organisms components

metabolism

Encompasses all the chemical reactions that occur in cell

Homeostasis

Maintenance of internal conditions within certain boundaries

Evolution

Process by which organisms change over time

Natural selection

Over time, individuals with the best combinations of genes are more likely to survive and reproduce

Adaptation

Inherited characteristic or behavior that enables organism to survive and reproduce successfully in its environment

Scientific theory

an explanation of natural phenomenon

Speciation

Formation of new species

Adaptive radiation

Evolution of multiple species from a single ancestral species, usually in response to available ecological niches (e.g. new habitats)

Differential reproduction

Adaptive traits increasingly represented in each succeeding generation

Fitness

Relative reproductive success of an individual

Artificial selection

Breeders choose traits by selecting animals and plants that will reproduce

Microevolution

Change in frequency of alleles in populations over time

Macroevolution

Large-scale changes (at species level and above) that result in extinction and speciation. Difficult to observe on geological time scale

Paleontology

Study of the fossil record

Fossils

Remains of once-living organisms often found in earth’s strata

Homologous structures

Anatomically similar structures inherited from a common ancestor, but may not serve the same function

Analogous structures

Not anatomically similar structures that do not share a common ancestor but serve the same function. A result of convergent evolution

Vestigial structures

Fully-developed anatomical structures that serve a reduced or obsolete function

Population

All the individuals of a species living in the same area at the same time

Gene pool

Total of all alleles of all individuals in a population for a given trait

Recombination, independent assortment, fertilization, mutation, and gene flow all promote what?

Genetic variation

What are the conditions for Hardy-Weinberg equilibrium

No mutations, no gene flow, random mating, no genetic drift, no selection

Causes of microevolution

Mutation, gene flow, nonrandom Marion, genetic drift, natural selection

Gene flow

Movement of alleles between populations

Nonrandom mating

Individuals do not randomly choose mates

Assortative mating

Individuals select mates with their phenotype and reject those with out

Sexual selection

Males compare for the right to reproduce and females choose the male

Inbreeding

Doesn’t change allele frequency, but does gradually increase the proportion of homozygotes

Genetic drift

Changes in allele frequencies of a gene pool due to chance

After a bottle neck, severe inbreeding, when founders start a new population

Causes of genetic drift

Bottleneck effect

Random event prevents a majority of individuals from entering the next generation causing the next generation to be composed of alleles that just happened to make it

Founder affect

New population started from just a few individuals. The alleles carried by population founders dictated by chance. Causes formerly rare alleles to either be more frequent or absent in new population

Orthogenesis

Variation has momentum that forces a lineage to evolve in particular pattern- not always adaptive

Directional selection

Curve shifts in one direction. Individuals at one phenotypic extreme at a disadvantage (ex- peppered moths)

Stabilizing selection

Peak of curve increases, tail decreases. Both phenotypic extremes at a disadvantage (ex-horseshoe crab)

Disruptive selection

Curve has 2 peaks

Zygote mortality, hybrid sterility, and reduced F2 fitness

Postzygotic reproductive barriers

Habitat isolation, temporal isolation, behavioral isolation, mechanical isolation, and gamete isolation

Prezygotic reproductive barriers

Allopathic speciation

An ancestral population is geographically isolated resulting in the evolution of separate species

Nonallopathic speciation

One population developed into two or more reproductively isolated groups

Phyletic gradualism

Evolution change occurs gradually over millions of years

Punctuated equilibrium

Evolutionary changes happen rapidly

Ecology

Study of the interactions among and between organisms and their abiotic environment

Biosphere

Portion of earth where living things exist. Atmosphere, hydrosphere, and lithosphere

Habitat

Physical location where a population lives. Includes abiotic and biotic factors

Resources

Environmental factors that animals use directly

Tolerance range

Range of values for a given abiotic factor that animals live within

Limiting factor

A factor outside an animals tolerance range

energy

The ability to do work

Autotrophs

Produce their own food

Heterotrophs

Obtain food from other organisms

Torpor

Lower body temperature and decrease metabolism (ex- humming birds)

Hibernation

Lower body temperature and decrease metabolism. Thermoregulatory center set point drops to 2 Celsius (ex- small mammals)

Winter sleep

Lower body temp but higher than true hibernators. Periods of inactivity

Brumation

Controlled hypothermia in ectotherms

Aestivation

Decrease metabolic rate while inactive in burrow. (Ex-invertebrates, reptiles, and amphibians)

Survivorship

Probability of survival to a particular age

Biotic potential

Maximum possible rate of increase with unlimited resources

Exponential growth

Optimal conditions allow constant reproductive rate

Logistic growth

Growth encounters environmental resistance

Environmental resistance

Environmental conditions that prevent populations from achieving biotic potential

Carrying capacity

Maximum number of individuals of a species the environment can continuously support

Density-independent factors (dif)

Environmental factor whose effects on a population is not influenced by changes in population density

Density-dependent factors (ddf)

Environmental factor whose effect on a population change as population density changes. Tend to regulate population at relatively constant size near carrying capacity

Community interactions

Competition, herbivory and predation, parasitism, commensalism, and mutualism

Intraspecific competition

Members of the same species compete for the same resource

Interspecific competition

Members of different species compete for the same resource

Competitive exclusion principle

No two species can occupy the same niche indefinitely. Compete for a resource that both require

Resource partitioning

Two species utilize different aspects of niche, both can survive

Character displacement

Where species co-occur, certain characteristics differ more than where they do not

Symbiosis

One species lives on or in another species

Mutualism

Both host and symbiont are happy

Commensalism

Host is neutral and symbiont is happy

Parasitism

Host is unhappy and symbiont is happy

Herbivory

Animal consumption of plants

Predation

Animal consumption of another animal

Mimicry

One species resembles another species possessing an anti-predator defense

Batesian mimicry

One species that lacks defense mimics another that has successful defenses

Mullerian mimicry

Several different species with the protective defenses mimic one another (ex- all stinging insects are black and yellow)

Self mimicry

One body part resembles another body part. Used by both predator and prey

Coevolution

Interdependent evolution of 2 interacting species

Keystone species

Play a greater role in maintaining the function and diversity of an ecosystem than would be predicted by their abundance

Ecological niche

Totality of an organisms adaptation, use of resources and life style to which it is fitted

Fundamental niche

Idealized niche of an organism

Realized niche

Lifestyle an organism pursues and resources uses

Succession

Gradual change in community’s species composition

Primary succession

Occurs in an environment that has not previously been inhabited by organisms

Secondary succession

Takes place after a disturbance destroys the existing vegetation

Ecological pyramids

Energy lost as it moves from one trophies level to the next

Biochemical cycles

Cycles of matter that involve biological, geological, and chemical interactions

Demographics

Statistical study of a population

Age structure

Diagrams represent number of individuals in each age group

Isolecithal

Very little yolk, evenly distributed throughout the egg

Mesolecithal

Moderate amount of yolk, concentrated at vegetal pole

Telolecithal

Abundant yolk, concentrated at vegetal pole

Centrolecithal

Large, centrally located mass of yolk

Holoblastic cleavage

Completely divides the egg. Occurs in Isolecithal and Mesolecithal eggs

Meroblastic cleavage

Cleavage furrow doesn’t completely divide cytoplasm. Occurs in Telolecithal eggs

Radial cleavage

Cells arranged in radial symmetry around animal-vegetal axis. Most deuterostomes