BIOL 2203 Exam 1

Taxonomy

Identification and naming of species

Taxon (taxa)

Generic term for any level of classification

Phylogeny

Describes the evolutionary relationships between species

3 sources of phylogenetic information

Comparative morphology, comparative embryology, and molecular biology

Cladogram

Groups all species that share derived characteristics

Outgroup

Group which is phylogenetically close to the group of study but is not included in the current study

Sister group

Monophyletic lineage most closely related to the monophyletic lineage being discusses

Clades

grouping of species that share a most recent common ancestor

Ancestral characteristics

Present in common ancestor

Derived characteristics

Newer forms of trans, relative to other organisms and serve as markers for evolutionary lineages

Synapomorphy

a trait that is shared by two or more taxa and previous ancestor did not possess the trait

Monophyletic

group contains an ancestor species PLUS all of its descendant species

Paraphyletic

group containing an ancestor species plus ONLY SOME of its descendent species

Polyphyletic

group containing more than one common ancestor. Not useful

Divergent

Speciation occurs and an ancestral species adapts to different resources

Convergent

Species adapt similar traits to use similar resources

Homologous structures

Structures with different appearances and functions that all derived from the same body part in a common ancestor

Hardy-Weinberg Principle

Allele frequencies in a population will remain constant from generation to generation as long as five assumptions are met

5 assumptions of Hardy-Weinberg

No mutation

No genres are transferred

Random mating is occurring

The population size is very large

No selection occurs

Mutation

A change in a cell’s DNA

Gene flow

Movement of alleles from one population to another

Nonrandom mating

individuals choose mates with specific genotypes

Genetic drift

random fluctuation in allele frequencies over time by chance

Selection

One of the phenotypes confers higher “fitness” in the environment

Biological fitness

number of genes passed on

Fitness is a combination of:

Survival, mating success, number of surviving offspring

What did Jean-Baptiste Lamarck proposed?

He proposed that acquired characteristics could be passed on

Natura selection

Environmental conditions determine which individuals in a population produce the most offspring

Macroevolution

Involves small changes in the DNA that accumulate through time

Disruptive selection

Acts to eliminate intermediate types

Directional selection

Acts to eliminate one extreme from an array of phenotypes

Speciation

Represents the process of species formation

Morphological species concept

Based in differences in anatomical features

This is the only species definition available for fossils

Biological Species Concept

If a species interbreed in a natural setting and have viable offspring, they are regarded as the same species.

Phylogenetic Species Concept

Uses both morphological and genetic data

Allows the construction an evolutionary tree (cladogram) to link life

Ecology

Study of the relationship of organisms to their environment

Abiotic factors (nonliving)

Space, energy forms including sunlight, heat, wind, and water currents, and the soil, air, water, and chemicals

Biotic factors (living)

Include other organisms as food, or competitors predators, hosts or parasites

Resources

Environmental factors that an animal uses directly

Fundamental niche

Describes animals potential role to live within a wider range of conditions

Realized niche

The narrower subset of suitable environments that an animal actually experiences

Population ecology

A population is a reproductively interactive group of animals of a single species

Survivorship Curves

Define the age pattern of a population from birth to death of the last member

Semelparity

The condition in which an organism reproduces only once during its life history

Iteroparity

The condition in which an organism reproduces multiple cohorts that may mature and reproduce while their parents are still alive and reproductively active

Population growth

Difference between rates of birth and death

Logistic growth

A population slows growth rate in response to diminshing resources

Density-independent factors

Abiotic factors reduce populations by floods, fires, storms, and severe climate flucuation

These agents kill young to other member or population regardless of the size of the population

Cannot truly regulate population growth because they are unrelated to population size

Density-dependent growth

Biotic factors that respond to density of the population

Food, water, disease, etc.

Species diversity

The number and distribution of species that share a habitat

Predator-prey interaction

Predator benefits and the prey is harmed

Parasitism

benefits the parasite and harms the host

Herbivory

benefits the animal and harms the plant

Commensalism

One species benefits and the other neither benefits nor is harmed

Mutualistic relationships

Both species benefit

Competition

Reduces the fitness of both

Niche overlap

Portion of the niche’s resources that are shared by two or more species

Competitive exclusion

Principle that no two species will occupy the same niche for a long time

Eventually one will exclude the other

co-evolutionary relationships

each in a race with the other

Mimicry

Harmless species mimic models that have toxins or stings

Keystone species

so pervasive to a community that its absence drastically changes the entire community

Primary producers

green plants or algae, fix and store energy from sunlight

Herbivores

First level of consumers that eat plants

Carnivores

Feed on herbivores or other carnivores

Decomposers

jfjfjfjjfjf

Ecological pyramids

Eltonian pyramids- abundance

Pyramid of biomass

Energy pyramids

Depicts rate of energy flow between levels

Parazoa

(para = alongside; zoon = animal)

Sponges lack true tissues

Tissues

Collections of cells that communicate to work together to complete a function

Mesophyl

jelly-like layer sandwiched between inner and outer layers

Spicules

Provide structure and defense

Choanocytes

flagellated cells for feeding

Ostia/Osculum

openings for water currents

Spongocoel

cavity within a sponge

Porocytw

Line pores of sponge

Pinacocyte

epithelial cells

Asconoid sponges

the simplest and least common

Water flows in through pours and enters spongocoel

Flagella move water upward and out through the osculum

Syconoid sponges

Have folded walls

Outer pores bring water in to radial canals leading to spongocoel

Leuconoid sponges

Have an extensively branched canal system leading from pores into flagellated chambers

Do not have a spongocoel

Water may be able to exit at multiple points

Monocious

Include both male and female reproductive parts

Gemmules

Dormant reproductive capsules