Biodiversity

BIOL 2040

Biodiversity

The variability among living organisms from all sources and the ecological complexes of which they are a part, including diversity within species, among species and ecosystem interactions.

Heritable

Variation within and between populations of organisms.

Cause for genetic diversity

Encoded in DNA, arises by mutations in gene and chromosomes

Chromosome

Chain of DNA code

Gene

Section of DNA along the chromosome that contains protein information. Helps create RNA

Alleles

A single gene with different forms. Dominate vs. recessive

Homozygous

Both alleles in an individual are the same. Ex) WW - two white

Heterozygous

Two different alleles present for one gene. Ex) WR

Phenotype

What you physically look like. Ex) Red vs. Pink vs. White

Genotype

What alleles are present. Ex) RR vs. Rr vs. rr

Mutation

Change in the sequence of bases of DNA along a chromosome. Can occur anywhere along a chromosome. Ultimate source of all genetic variation.

Fitness

Relative reproductive success of a genotype in a given environment.

Deleterious Alleles

Random changes that can cause harm by lowering fitness, often eliminated in selection.

Neutral Allele

Random changes that don’t have an effect

Allele Frequency

Show diversity of individual in a population

Percent of Heterozygosity

Shows diversity in an individual

Natural Selection

Increases the frequency of alleles that contribute to reproductive success in an environment.

Natural Selection Conditions

Phenotype variation, reproduction excess and non-random reproduction of genotypes

Directional Selection

Changes the average phenotype in a population in one direction

Stabilizing Selection

Reduces genetic variation in a trait but doesn’t change average value of a trait over time

Disruptive Selection

Intermediate phenotypes are selected against and extreme one are favored - increased variation in traits.

Balancing Selection

When no single allele has a distinct advantage.

Speciation

Formation of a new species

Sexual Selection

Female chooses certain males and/or males compete against themselves to secure mates

Honest Signals

Male genetic qualities can indicate males can care for young and provide resources

Male/Male Competition

Competition is the primary cause for sexual selection

Sexual Dysmorphism

Any trait that differs between male and female between the same species. Ex) color, size, behavior

Scientific Theory

Not a guess, explains a broad class of observations and it widely supported by evidence. Uses patterns and process

Evolution

Change in allele frequencies in a population over time. Happens over a period of time with modifications to alleles to produce modern, modified species who share a common ancestor.

Species

A group of interbreeding natural populations that are reproductively isolated from other groups

Population

Group of individuals of a given species in a particular geographic area

The Biological Species Concept

Physical mechanism of reproductive isolation (temporal, habitat, behavior, gametic barrier, mechanical hybrid viability, hybrid sterility). Can only be applied to populations that overlap geographically.

Prezygotic Isolation

Individuals of different species are prevented from successfully mating

Postzygotic Isolation

Hybrid offspring do not survive reproduce

The Morphospecies Concept

Individual lineages differ in size, shape or other morphological features. Most likely arise if populations are independent and isolated from gene flow

Polymorphic Species

Species that classifies in more than one group

Cryptic Species

Species that differ in non-morphological traits

Subspecies

Population that live in discrete geographic areas, have distinct features but not enough to be a different species. Can interbreed with other species.

Gene Flow

Exchange of genetic material within a population, between populations of a species and between species

Allopatric Model (Isolation)

Species arise when individuals become isolated

Sympatric Model (Isolation)

Speciation of non-isolated individuals is possible but less frequently observed

Divergent evolution

New species evolve and become more different. Can lead to adaptive radiation

Convergent Evolution

Unrelated organisms seem to resemble on another. Usually because the evolved in similar environments

Species Richness

Number of species in an area

Species Abundance

Relative commonness of species

Patterns in Space

Biodiversity tends to be higher in the tropics. Latitudinal gradients in biodiversity (higher latitude = fewer species). Each continent has their own scale patterns.

Endemism

Species that are unique to a single area. Often found in temperate regions. Can greatly vary but often occurs among mammals, birds and plants

Annual Migrations

Species that migrate on an annual basis to more tropic areas

Dormancy/Hibernation

Species that disappear physiologically during winter/drought. Lots of diversity is hidden this way.

Phylogenetic Tree

Graphical summary of history. Shows evolutionary relationships between species and higher taxa. Most universal is the tree of life. Are often hypothesis

Branch

Represents a population through time

Node/Fork

Represents a point where a branch splits and most recent ancestor

Tip (Terminal Node)

Represents the endpoint of a branch (living or extinct)

Taxon

A taxonomic group of any rank such as species, family or class

Polytomy

A node that divides into three or more branches

Root

The next ancestorial point in the tree

Sister Groups

Closely related taxa that share a common ancestor

Character/Trait

Any genetic, morphological, physiological or behavioral characteristic to be studied in a matrix

Ancestral Trait

A characteristic that is present in a common ancestor

Derived Trait

One not present in the common ancestor

Cladistic Approach

First method to infer Phylogenetic tree from morphological traits

Synapomorphies

Trait found in two or more taxa, present in their most recent common ancestor but missing in more distant ancestor. Allows biologist to recognize morphologic groups

Parsimony

Used to identify the most likely tree. Principal of logic and states the most likely explanation or pattern is the one that implies the least amount of change

Homology

Occurs when traits are similar die to shared ancestry

Homoplasy

Occurs when traits are similar for other reasons then common ancestors

Analogous Structure

Similar idea across species but dissimilar in ancestry. Ex) human arms and bird wings

The Tree of Life

The deepest division of life. Shows ancestors of all current diversity started from the same place.

Prokaryotes

One-cell, no compartments within the cell. Genetic material is a single circler chromosome with only one copy of each gene. Have influence on nitrogen cycle. Ex) Bacteria and archaea. 10,000 to 15,000 recognized species.

Eukaryotes

One-cell or multi-cellular with compartments. Genetic material is two or more linear separate chromosomes with two or more copies of each gene. Much less metabolic diversity. Ex) Protists, fungi, animals and plants (vast majority of biodiversity comes from this group)

Microorganisms

Single-celled, mostly viruses

Viruses

Functional biological units that have genetic material, can replicate, evolve, occupy specific ecological niches and have variability.

Protists

Any organism that doesn’t fit into one group or doesn’t form a natural group. Polyphyletic with many clades and taxa evolving from last common ancestor. Producers and consumers that sexually reproduce. Ex) protozoan, fungi and algae

Plants

Anything that uses photosynthesis using chlorophylls A and/or B. Store starch in chloroplasts and have cell walls made of cellulose.

Green Algae

Ancestor of terrestrial plants. Primary producer in fresh water systems. At least 7,000 species. Ex) Seaweed

Bryophytes

First plants on land. NO vascular tissue making them stay low to the ground. Reproduce by shooting spores out onto the ground. Need moist living conditions. Ex) hornworts, mosses, liverworts

Land Ferns

First with vascular tissue, can now grow taller. Reproduce by releasing spores. Need damp living conditions. What we burn for “fossil fuels”

Gymnosperms

First seed plants. Protect sperm/egg producing structure, make pollen to carry sperm by the wind. Produce/nourish seeds by using stored energy. Can now live in dryer areas. Seeds are typically stored in a cone. Ex) pine trees

Flower Plants

Use pollen to carry protect sperm by the wind. Use animals for “special delivery” of pollen to the right species and continue making seeds. Adapt seeds and fruit to particular dispersal agents.

Fungi and Animals Relationship

Shared a common ancestor based on genetic data. Cell membrane and other complex biosynthetic pathways are similar.

Fungi

Spore producing organisms the feed on organic matter through absorption. Multicellular with unique chromosome and nuclear division features. Can grow in wide variety of conditions.

Chytrids (Fungi)

Aquatic fungi, reproduce with flagellum/sperm characteristics. Ex) frog killing

Ascomycetes (Fungi)

Filamentous except for yeast. Mostly decomposers or parasitic with 30,000 species. Ex) yeast, Dutch elm, disease, Chestnut blight, edible fungi and antibiotics

Basidiomycetes (Fungi)

Decomposers or pathogens with 25,000 species. Ex) edible or poisonous

Mycorrhiza (Fungi)

Symbionts between fungus and plant roots. Important in evolution.

Animals

Multicellular organisms that have nervous system tissue and muscle tissue. Internal circulation system, can exchange gas (lungs/gills) and are mobile.

Early Animal Linages

Least specialized of all animals. Lack tissue and other basic structures. Ex) Sponges

Radiata (Animals)

Radial symmetry is adapted to move sedentary lifestyles where an organism stays on one place and finds needs easily in an environment. Often have stringy tentacles. Ex) jellyfish, coral, sea anemones

Radial

Parts radiate from center, any plane creates two equal halves

Bilateral (Animals)

Bilateral symmetry is adapted for an active lifestyle where organisms move to obtains food or detect/respond to stimuli. Associated with concentrated sensory function into the head. Three major groups have various specializations in the formation of the body cavity.

Bilateral

Has two side, plane must be placed in one spot to get equal sides

Annelids and Friends (Animals)

Marine creatures, incredible diverse group with 93,000 species. Second largest animal phylum. Ex) Gastropod, Cephalopoda, Bivalvia

Arthropods and Friends (Animals)

Moat success linages with 1 million species. Four major groups (chicaneries, crustaceans, unrienmia, trilobites). All feature body segmentation, tagmosis, exoskeletons, segmented appendages and well developed ceptialization.