Diversity of Life 11-10-14 6:37 PMBio Notes- Diversity of Life Test

Determining how species are related:

Goal of modern classification: assign species to a taxa (category) such that their classification reflects morphological similarities and evolutionary historyAncestor: organism from which other groups of organisms are descendedIf common ancestor is shared, species are closely relatedEg. Family canidae- share elongated snouts, 5 toes on front feet and four on back (includes dogs, wolves, foxes)Likely had a common ancestor (eg grey wolf- common ancestor of domestic dog)

Evidence of relationships among species

Three main types:Anatomical evidence- determine common ancestor through morphological similaritiesPhysiological- studying biochemistry of organisms, look at proteins they make (gives an idea of the genes they have). Through comparing proteins, degree of genetic similarity can be determinedDNA evidence- genes are made of DNA, and with improvements in technology, scientists can properly classify organisms through DNA examination. This is the most accurate form of evidence. Eg. Fungi was thought to be more closely related to plants but DNA evidence shows it is more similar to animals

Phylogenic Tree- branching diagram used to show evolutionary relationships among species

Species Concepts

Scientists can’t decide what a species is, so have species concepts. There are three main types of species concepts:1. Morphological Species Concept: focus on body shape, size, and structural features to compare organisms.Advantage: simple, so most widely usedDisadvantage: challenge to decide how much difference is too much, since all organisms vary to some degree2. Biological Species Concept: defines species by whether two organisms can produce fertile offspringAdvantage: widely used by scientistsDisadvantage: can’t be applied in all cases, eg. Asexual reproduction, extinct animals3. Phylogenic Species Concept: focuses on species’ evolutionary history Advantage: can be applied to extinct species, and uses information from DNA analysisDisadvantage: evolutionary history not known for all species

Naming and Classifying Species

Use binomial nomenclature, a two part name consisting of the genus name and the species nameGenus name usually noun in Latin or GreekSpecies name usually an adjective in Latin or GreekDeveloped by Carl Von Linne/ Carolus Linneas Also developed hierarchal system for classification (nested system)Each category known as a rank, called a taxon

As you move down ranks, becomes more specific

Eukaryotic Kingdoms

DomainKingdomPhylumClassOrderFamilyGenusSpecies

Kindgom Nutrition Cell Wall Reproduction

Protista Autotrophs and heterotrophs

Cellulose in some, some lack cell wall

asexual and sexual

Plantae Autotrophs Cellulose Sexual

Fungi Heterotrophs Chitin Sexual

Animalia Heterotrophs No cell wall Sexual

Classifying Types of Biodiversity

Species DiversityVariety and abundance of species in a given area

Genetic DiversityVariety of heritable characteristics (genes) in a population of interbreeding individualsGenes: genetic material that controls expression and inheritance of traitsPopulation: group of individuals of same species at specific place at specific timeGene pool: all genes of all individuals in populationGenetic diversity within a species is always greater than within a population because gene pool will be larger (contain more combinations of genes)Why so important?Resistance to disease

Survival against changing environmental conditionsConservation biology

Ecosystem DiversityVariety of ecosystems in the biosphereComposed of biotic and abiotic factorsBecause of diversity among organisms and abiotic factors, Earth varies a lot physically and chemically, so VERY rich ecosystem diversityImportant because of ecosystem services: benefits experienced by organisms provided by sustainable ecosystemsEcosystems with greater species diversity more likely to reliably provide important ecosystem services, and demonstrate more resilience (ability to maintain equilibrium despite outside disturbances to ecosystem)

Viruses

A structure that contains strands of DNA or RNA surrounded by a protective protein coat. They cannot live independently of cells, and are classified by organisms they infect. They are not formally considered an organism.

Anatomy:Capsid: outer protein that surrounds genetic material of a virus. It a) protects nucleic acid from enzyme digestion, and b) provides proteins to allow attachment to host cellsTail sheath: a needle-like part of virus that penetrates cell wall of bacteria like a needle to inject the viral nucleic acid into the host cellTail fiber: like landing gear, it helps the cell attach to the bacterium surfaceGenome: complete DNA or RNA sequence

Differences between bacteria and viruses:Viruses aren’t formally considered an organism, as without a host cell they can’t sustain themselves, reproduce, synthesize proteins, or generate energyViruses have no organelles, just a protein coating around the genomeViruses are 1000x smaller (10nm to 1 micrometre)

Lytic Cycle:Attachment: protein on surface of virus binds to protein receptors on the surface of the host cell membraneEntry: virus injects genetic material into host cell and breaks down host cell’s DNAReplication: host cell makes more of virus’s RNA or DNA and creates protein using nutrients from within host cellAssembly: new viral particles are producedLysis and release: host cell bursts open and releases new viral particles, rupturing cell wall/membrane. It can create up to 100-200 new virus cells per cyclelethal cycle: kills host cellperformed by bacteriophages- bacteria killers

Lysogenic Cycle:Provirus formation- viral DNA becomes part of host cell’s chromosomesBacterium reproduces normally, copying prophage and transmitting it to daughter cellsMany cell divisions produce colony of infected bacteriaOccasionally, prophage exits bacterial chromosome initiating lytic cycle* Virus’s genetic material enters host cells chromosome but is not activated until later- lies dormant

RetrovirusesAny virus that inserts a DNA copy of its genome into a host cell in order to replicateLife Cycle:Cell membrane and viral membrane fuseReverse transcriptase turns one RNA strand into DNA using nucleotides. It has poor proofreading so often makes mistakesRNA is reverse-transcribed again into double stranded DNANew double stranded DNA is inserted into the host chromosome by going through nuclear membraneMessenger RNA that is made by new double stranded DNA is sent out of the nucleusmRNA makes viral proteins using ribosomes in the endoplasmic reticulum2 mRNA and viral proteins bud off cell’s surface, creating a new virusProteins are digested and a new virus maturesBacteria

Diversity:Rods (bacilli), spheres (coccus) and spirals (spirillum)On their own- mono, in lines- strepto, in clusters- staphylo, double- diplo

Prokaryote structure:Unicellular1/10th of eukaryotic cell in size (~ 1 micron)No membrane bound organelles, only ribosomesCircular chromosome, naked DNA not wrapped around proteins

Test 2- 11-10-14 6:37 PMTheory of Endosymbiosis

Theory of how eukaryotic cells became able to make energy (chloroplasts and mitochondrion)

Pretty much the cell ‘eats’ (engulfs) a bacteria that performs cellular respiration, and that eaten bacteria became a mitochondrion

Suggests that chloroplasts and mitochondria were once free-living organismsEvidence:

Their membranes both resemble those of living prokaryotes Their ribosomes looks much more like prokaryotic ribosomes than elsewhere in the

eukaryotic cell They reproduce by binary fission Each contains a circular chromosome, and many gene sequences match those of living

prokaryotes.

Protist Kingdom

Eukaryotes who are not animals, plants or fungi Ridiculously diverse, so much that classifying them is a challenge because it doesn’t

represent an evolutionary relationship between all memberso Paraphyletic: fit into different phylogenetic places

Fully diverse: uni/multicellular, auto/heterotrophs, a/sexual reproduction, pathogenic/beneficial, sessile/mobile

Move with flagellum, cilia, or pseudopods (amoeba)o Pseudopod: part of the body that is like slimy jello, that the amoeba extends out,

causing the rest of the body to follow

Animal-like Protists- Protozoans Heterotrophs, predators, and many are parasitic Eg. Amoebas, paramecium, flagellates, sporozoans

Plant-like Protists Autotrophs, photosynthesize (have chloroplasts) Eg. Algae (red/green/brown), Euglenoids, Diatoms, Dinoflagellates

Fungi-like Protists Plasmodial slime mould, cellular slime mould, or water moulds Heterotrophs but rather than ingesting other organisms

Parasitic protists: sporozoans- malaria, Giardia, trypanosomesBeneficial protists: phytoplankton- produce 90% of atmospheric O2 through photosynthesis, zooplankton- key ecological role at base of marine food web (food for lots of animals)

Fungi

- predominant body form: mycelium-tangled mass of branched filaments called hyphae- flowering body is like the part of the thing that we see… like a legit mushroomClassificationA. Imperfect Fungus- mould penicillin, cyclosporine, thrush throat infectionB. Chytrids- unicellular, aquatic, eg. What causes potato wartC. Zygospores- multicellular, terrestrial, common moulds D. Sac Fungi- Develop small finger-like sacs called asci, eg. Yeast, truffles, fungal component of most lichenE. Club Fungi- mushrooms, puff balls, stinkhorn

Plants

Had to overcome 4 main challenges to adapt to terrestrial life:o Desiccation (drying up) o Transporting fluids from place to place o Physical supporto Reproductive/dispersial strategies

To overcome, they developed the following strategies:o Waxy, waterproof cuticle with openings called stomatao Vascular tissue to conduct fluids (veins and arteries of plants)

Xylem- transports water and inorganic nutrients Phloem- transports organic products of photosynthesis

o Rigid stems and other support structures evolved to hold leaves up to the sun (cell wall, stems, woody tissue)

o Reproductive strategies where water is not needed like seeds (pollination, attractive colours, sap)

Non-vascular Plants Bryophtyes:

Can’t grow tall, b/c no vascular tissue to provide support or transport Cuticle on upper surface only, water enters through lower pores No true roots Mosses, liverwort, hornwort

Vascular Plants- Tracheophytes More complex, grow larger than bryophytes

Without seeds:

Club mosses, ferns, horsetails Ferns reproduce with a spore of water, although they can survive drier conditions because

they have true roots, more resilient leaves, and better developed vascular tissue

With Seeds:

Land plants that evolved were adapted due to woody tissues (lent strength to plants so they could grow tall), more complex vascular tissue (enabled water and nutrients to be carried to new heights), and seeds and flowers (don’t need a film of water to reproduce)

The seed: drought resistant reproductive package that houses a dormant plant embryo (partially developed plant able to grow into a mature one) and a supply of food (cotyledon). A hard outer seed coat covers both the embryo and the cotyledon

Gymnosperms (vascular plants, with seeds, naked seed) Fist plants to evolve seeds Seeds aren’t enclosed in a covering- most develop uncovered on scales within cones Coniferophyta- conifers

o Male and female gametes produced on different cones o The gametes produces pollen in the male and the egg in the femaleo The male cone: soft, short-lived, closed pineconeo Female cone: hard, longer lasting, made of scales on which the egg develops

Angiosperms (vascular plants with needs that flower) Produce seeds enclosed in fruit and the male and

female gametophytes are reduced to a few cells living on the plant (ovum and pollen)

Flowers are used to attract insect pollinators, fruit used to attract herbivores that can disperse seeds

Monocot (vascular plants with seeds that flower that have one cotyledon)

Vascular bundles: scattered

One cotyledon Flowers in multiples of three Mature leaves usually parallel

Dicot (vascular plants with seeds that flower that have two cotyledons) Vascular bundles arranged in a ring 2 cotyledons Flowers in multiples of 4 or 5 Usually net-like leaves

So their classification goes: Vascular tissue? (if no, bryophytes. If yes, tracheophytes.)Seeds? (if no, mosses, horsetails. If yes,well they have no name)Naked seeds or flowering? (If naked, gymnosperms. If flowering, angiosperms)One or two cotyledons? (if one, monocot. If two, dicot.)

Animals

Characteristics Heterotrophs Multicellular- complex bodies No cell walls- allows active movement Sexual reproduction- no alternation of generations, no haploid gametophyte

Animal Phyla:

Symmetry

Coelom

Segmentation

Body Other Examples

Porifera none no no soft No tissues or organs

Sponges

Cnidaria radial no no soft Specialized tissues, no organs

Jellyfish, coral, sea anemone

Patyhelminthe

s

bilateral no no soft Start of cephalization

Flatworm, tapeworm

Nematoda bilateral Sort of (pseudo-coelmate)

no soft Start of digestive system

Round-worm

Annelida biltaeral yes Inside and out soft Distinct head and organs

Segmented worms, leeches

Mollusca bilateral yes no Soft, shells Stomach, head, or hatchet footed

Clams, slugs, snails, squid

Anthropoda bilateral yes Specialized segments

exoskeleton Most successful phylum

Spiders, scorpions

Echinodermat

a

radial yes no endoskeleton

Can regenerate parts

Sea urchin, starfish

Chordata bilateral yes yes endoskeleton

backbone Humans, birds, dogs

Vertebrae Subgroups

Fish Amphibians Reptiles Aves Mammals

Body Bony or cartilaginous, with scales

Legs, moist skin, bony skeleton

Dry skin, scales, armour

Feathers and wings, follow bones

Hair, specialized teeth

Gas exchange Gills to get O2 Lungs and diffusion through skin

Lungs Efficient lungs and air sacs

Lungs, diaphragm

Heart 2 chambers 3 chambers but some mixing

3 chambers, less mixing

4 chambers, no mixing

4 chambers, 2 loops

Ecto/endotherm Ectotherm Ectotherm Ectotherm Endotherm EndothermFertilization External External Internal Internal InternalDevelopment External,

amniotic eggExternal, in aquatic egg

External in amniotic egg(leathery)

External in amniotic egg

Internal in uterus or pouch

Other Joined, paired appendages

Metamorphosis

Claws for defense

Specially designed to fly

Birth live young

Examples Trout, shark, salmon

Frog, salamander

Dinosaur, turtle, lizard

Hawk, eagle Humans, kangaroos

Sub-groups of Mammals (it just never ends!) Monotremes:

Egg laying mammals Lack placenta and true nipples Eg. Platypus

Marsupials:

Pouched mammals, offspring feed from nipples in pouch

Short lived placenta Koala, kangaroo, opossum

Placental

True placenta, nutrient and waste filter Shrews, bats, whales, humans

Biodiversity Crisis

Current decline in the genetic, species and ecosystem diversity that may represent a mass extinction

Common threats to species today include: o Habitat destruction o Invasive specieso Illegal tradeo Pollutiono Climate change

Scientists study the impact of climate change by examining long-term data, exposing small ecosystems to artificial climates, and by making predictions and seeing if it comes true

Climate Change Affects raindeer and caribou by causing less growth/access to lichens, resulting in less food Also interrupts migration matterns and reproduction patterns

Climate Change and Habitat Affects average temperature Mountains- shifts ecosystems further up the mountain as they try to stay in the right

temperature, and some sill go extinct Means more competition for food

Climate Change and Reproduction Many species follow temperature-sex determination where temperature determines sex If temperature rises, there will be too many males and too few females If population is over 75% male it can’t survive

Climate Change, Plant and Animal Pollinators Pollination relationships may lose their matched timing, because It may make plants or

insects become active earlier than normal An insect may emerge but the flowers may not be ready, and when they are there may be

to few insects around

Climate Change and Aquatic Ecosystems Increasing the temp. can affect freshwater organisms Can cause growth rates of invertebrates to increase, insects to emerge earlier, male-

female ratios to change Decrease appetite and growth of fish in summers but opposite in winter