Bio 112 Final Exam

Polyphagous Parasites

Parasites that can feed on multiple hosts

Resource Partitioning

• Mechanism where species divide available resources to reduce competition.

• The differentiation of niches, in both space and time, that enables similar species to coexist in a community.

Allelopathy

Process where plants release chemicals to inhibit the growth of nearby competing plants

Iteroparous

Organisms that reproduce multiple times throughout their life

Cotyledons

Seed leaves of flowering plants

Transpiration

• Process where plants release water vapor through pores in their leaves.

• The process by which water evaporates from the aerial parts of plants, usually via the stomata of leaves.

Ethylene

Plant hormone involved in fruit ripening and senescence.

• Promotes seedling growth, induces fruit ripening

• Plays a role in leaf and petal aging and drop

• Coordinates defenses against osmotic stress and pathogen attack

Cytokinins

Plant hormones that promote cell division and growth

• Promote cell division, influence cell specialisation and plant aging

• Activate secondary meristem development, promote adventitious root growth

• Promote shoot development on callus

Vascular Bundle

Structure in plants that contains xylem and phloem for nutrient transport

Metamorphosis

Process of transformation in insects from larva to adult form

Parthenogenesis

A form of asexual reproduction where an egg develops without fertilization

Secondary Metabolites

Chemical compounds produced by plants that are not essential for growth but may have ecological functions

Endosperm

Tissue in seeds that provides nutrients to the developing plant embryo

Alternation of Generations

Life cycle where plants alternate between a haploid and gametophyte and a diploid sporophyte generation

Supergroup Amoebozoa

A diverse group of amoeboid protozoa and slime molds

• Move using pseudopodia

Phytophthora Infestans

Oomycete pathogen responsible for the Irish potato famine

Stramenopiles

Diverse group of protists with hairy flagella

Phagotrophy

Nutritional mode where organisms ingest food particles

Plasmodium Falciparum

Protozoan parasite that causes malaria in humans

Quorum Sensing

Communication system used by bacteria to coordinate gene expression based on population density

Thylakoids

Membrane-bound compartments inside where photosynthesis takes place

Phylogeny

Evolutionary history of a group of organisms

Homology

Similarity in traits due to shared ancestry

• Can be developmental, anatomical, or molecular

Macroevolution

Large-scale evolutionary changes over long periods

Microevolution

Small-scale changes within a population

Kin-selection

Acts of self-sacrifice indirectly promote the spread of an organism’s genes

Group Selection

Group containing altruists would have a survival advantage over group composed of selfish individuals

Individual Selection

• more likely because:

• Mutant individuals that use resources have an advantage over those that conserve resources

• Selfish individuals can immigrate from other areas

Intrasexual Sexual Selection

• Members of one sex compete for partners and the winner gets most of the matings

• Mate competition between individuals

• In many species, females do not actively choose between males

• Instead they mate with competitively superior males

Intersexual Sexual Selection

• Member of one sex chooses mate based on certain characteristics

• Often based on plumage color or courtship displays

• Female choice

Natural Selection

• More offspring produced than can survive

• Competition for resources

Hardy Weinburg Equation and Conditions

• No new mutations

• No natural selection occurs

• No migration

• Random mating

• Allele frequencies do not change

Directional Selection

• Individuals at one extreme of the phenotypic range have greater reproductive success in a particular environment

• Initiators

  • New allele with higher fitness introduced

  • Prolonged environmental change

Stabilizing Selection

• Favors the survival of individuals with intermediate phenotypes

• Extreme values of a trait are selected against

• Clutch size

  • Too many eggs and offspring - die due to lack of care and food

  • Too few eggs - does not contribute enough to next generation

Disruptive/Diversifying Selection

• Favors the survival of two or more different genotypes that produce different phenotypes

• Likely to occur in populations that occupy heterogeneous environments

• Members of the population can freely interbreed

Balancing Selection

• Maintains genetic diversity

• Balanced polymorphism

  • Two or more alleles are kept in balance, and therefore are maintained in a population over the course of many generations

• Two Common Ways

  • For a single gene, heterozygote favoured

  • Negative frequency-dependent selection

    • Rare individuals have a higher fitness

Prezygotic Barriers

Prevent formation of zygote

Postzygotic Barriers

Block development of viable, fertile individuals

Habitat Isolation

Geographic barriers prevent contact

Temporal Isolation

Reproduce at different times of the day or year

Behavioural Isolation

Behaviours important to mate choice (ex: changes in song)

Mechanical Isolation

Size or incompatible genitalia prevent mating

Gametic Isolation

• Gametes fail to unite successfully

• Important in species that release gametes into the water or air

Hybrid Inviability

Fertilized egg cannot progress past an early embryo

Hybrid Sterility

Interspieces hybrid viable but sterile (ex: mule)

Hybrid Breakdown

Hybrids viable and fertile but subsequent generations have genetic abnormalities

BMP4

Causes cells to undergo apoptosis and die (Chicken)

Gremlin

Inhibits the function of BMP4 and allows cells to survive (Ducks)

Gram Positive

• Relatively thick peptidoglycan layer

• Purple dye held in thick layer

• Cells are stained purple

• Vulnerable to penicillin that interferes in cell wall synthesis

Gram Negative

• Less peptidoglycan and a thin outer envelope of lipopolysaccharides

• Lose purple stain but retain final pink stain

• Cells are stained pink

• Resists penicillin and requires other antibiotics

How many animal phyla?

35

Turgor Pressure

The hydrostatic pressure required to stop the net flow of water across a plasma membrane due to osmosis