Biology Unit 4

Appendix I Species

species threatened with extinction, no trade

Appendix II species

species that may become threatened, limited trade

Appendix III Species

trade allowed by CITES

3 Definitions of Species

morphospecies, phylogenetic, biological

Morphospecies Concept

members of the same species usually look alike

Pros of Morphospecies Concept

easy to identify visually

Cons of Morphospecies Concept

mimicry

Phylogenetic Concept

identifies species based on evolutionary history, related to common ancesto

Pros of Phylogenetic Concept

applicable to any type of population, different species have different traits due to lack of gene flow

Cons of Phylogenetic Concept

phylogenies are available to subsets of populations, lead to recognition more species

Species

a unique group of organisms that share a common ancestor

Biological Concept

groups of actually or potentially interbreeding populations that are reproductively isolated from other such groups

Pros of Biological Concept

easy to identify

Cons of Biological Concept

asexual organisms, can’t be evaluated for extinct species, species like plants may produce hybrids

Microevolution

change in allele or genotype frequencies in a population, over time or a few generations

Macroevolution

origin of new species, over very long periods of time

Allopatric speciation via dispersal

population moves to a new habitat, colonizes it, finds new population

Allopatric speciation via vicariance

physical splitting of a habitat

How does dispersal and vicariance lead to allopatric speciation?

They create geographic isolation

Sympatric speciation

occurs among populations within the same geographical area

How can disruptive selection result in sympatric speciation?

Among a species in a geographical area, the 2 extreme phenotypes are favored compared to the middle, which causes the population to split

Biological community

consists of all the populations of interacting species living within a define area

Commensalism

one organism benefits and other is unaffected (+/0); too much can cause competition between the 2 species

Ex: epiphytes on trees gaining benefits, but too many will cause competition for sunlight

Competition

competiting uses resources that can’t be used for foraging, mating , or other activities to increase fitness (-/-)

Ex: pack of wolves hunting for deer or other food resources so they don’t compete with each other

Intraspecific competition

occurs between members of the same species (population)

Interspecific competition

occurs between members of different species

Consumption

organism acquires or uses a resource (+/-)

Ex: wolves eat a deer

Mutualism

both species benefit from interaction (+/+)

Ex: bees get nectar and pollinate flowers

Ecological Niche

range of resources that a species can use and the range of conditions it can tolerate

Ex: what types of seeds a bird can eat based on their beak’s size

3 Outcomes of Competition

realized niche, competitive exclusion, coexistance/niche differentiatio

Realized niche

minimized ecological niche, which is the parts of the niche that are not as competitive

Competitive Exclusion

a weak competitor has narrower niche and there are fewer individuals in the population

Coexistence/niche differentiation

individuals are cut out by natural selection

Herbivory

consumption of plant or algal tissues by herbivores

Predation

killing and consumption of most or all of another individual (prey) by an individual

Parsitism

consumption of tissues from another organism, or host, by a parasite

Sister group

single ancestral lineage gives rise to 2 daughter lineages

Outgroup

sister group that shares a recent common ancestor with a taxa being studied

Clade

group of organisms that includes a single ancestor and all of its descendants

Ancestral trait

characteristic that existed in an ancestor

Derived trait (synapomorphy)

modified form of the ancestral trait, found in a descendant (new trait evolution)

Shared character

shared within a lineage

How is parsimony used to find most likely evolutionary sequence of a group of organisms in a phylogeny (evolutionary history of a group of organisms)?

Tree with the least evolutionary change is most likely the one that most accurately reflects what occurred during evolution

Homology

similarity in organisms due to common ancestry

Homoplasy

similarity in organisms due to resources other than common ancestry

Monophyletic group

evolutionary unit that includes an ancestral population and all of its descendants (clade group)

Polyphyletic group

unnatural group that doesn’t include the most recent common ancestorP

Paraphyletic group

gropu that includes an ancestral population and some of its descendants

Convergent evolution

development of similar traits due to similar environmental pressures, occurs in homoplasy

What are the 2 main outcomes of interactions among species?

influences distribution and abundance of interacting species, species are agents of natural selection which influences the fitness of the population