Diversity of Life Flashcards
Gram-positive bacteria
- Stain dark purple
- Thick peptidoglycan layer in cell wall
- No outer (second) membrane
- Relatively small periplasm
- No (endotoxins) lipopolycaccharide (LPS)
- Secrete exotoxins
- Contain teichoic acids (acidic polysaccharide connecting peptidoglycan layer and plasma membrane for rigidity and structure
Gram-negative bacteria:
- Stain pink (due to counterstain)
- Thin peptidoglycan layer in the cell wall
- Contains periplasm between inner and outer membrane
- Outer (second) membrane present
- LPS present (an endotoxin release when bacteria is destroyed)
- Secrete exotoxins
- No teichoic acids
Cell wall of archea
No peptidoglycan present in cell wall, instead they contain some pseudomurein (a molecule that is analogous to peptidoglycan but with different peptide cross bridges)
Cell walls are also composed of sugars, proteins and inorganic molecules
Cell wall of eubacteria
Peptidoglycan present (a carbohydrate and protein polymer), encompassing the entire bacterial cell wall and allows for anchoring
The peptide and carbohydrate cross bridge linkages have D-amino acids that provide structural integrity
DNA organization of archea
- Circular
- Utilize histones and introns
DNA organization in eubacteria
- Circular
- Lack histones and introns
Endospores
- Produced by some bacteria
- A tough, non-reproductive structure that allows bacteria to enter a dormant state
- In the dormant state, the cell’s genetic material is preserved, allowing the cell to survive during times of extreme environmental stress
Fungus-like protists
- Lack a cell wall made of chitin
- Can move with flagella and cilia
- Saprophytic: feed on decaying matter
- Most live in moist soil
- Ingest food via phagocytosis
- Asexual reproduction and sporulation (spores produced have thick and strong cell walls allowing to resist environmental conditions
Plant-like protists
(algae-like protists)
* Among the most important primary consumers
* Photosynthetic autotrophs: produce organic matter from inorganic molecules using photosynthesis
* Examples: diatoms, euglenoids and dinoflagellates —> unicellular, photosynthetic autotrophs that reproduce asexually and are found in aquatic environments
Dinoflagellates
Responsible for red tide (toxins build up, oxygen in water is depleted)
Posses 2 flagella (find food in the absence of light)
Can parasitically infect certain animals (heterotrophic)
Animal-like protists
- Known as protozoa
- Eukaryotic (membrane-bound organelles)
- Unicellular
- Heterotrophic
- Move via flagella and cilia
- Often parasitic pathogens that infect and feed off a host organism (consume living cells or dead organic matter
- Contain food vacuole to store food
- Ingest food via phagocytosis
Kingdom fungi key features
- Heterotrophic sporophytes: feed on decaying/dead matter
- Posses a cell wall contain the polysaccharide glucan
- Have a predominantly haploid life cycle
Nonfilamentous fungi
- Yeast
- unicellular
- Reproduce asexually by budding
- Facultatively anaerobic: utilize fermentation in absence of oxygen to convert glucose to carbon dioxide and ethanol
Filamentous fungi
- Molds
- Multicellular and multinucleate
- Undergo aerobic respiration (require oxygen to gain energy from food)
- Reproduce sexually
- Form hyphae
Hyphae
Long, branching filaments that extend out to form a network of fungi (mycelium) with nearby fungi
› Collectivley all the hyphae are known as mycelium, which includes all connected spores
Septate hyphae
- Have septum dividing hyphae into multiple sections/compartments
- Causes the mycelium to look segmented
- Cell division occurs with cytokinesis which generates the individual septa as the cell grows
- Each compartment has a single nucleus
- Septa can close if injured and septa increases structural stability
Coenocytic hyphae
No septa present
One long continuous multinucleate cell (coenocyte)
Cell division occurs without cytokinesis
No septa allows for rapid nutrient diffusion
Phylum Platyhelminthes general characteristics and examples
- Reproduce sexually (hermaphrodites) or asexually (regeneration)
- Mainly aquatic habitats
- Parasitic lifestyle
- Most primitive of triploblasts
- Have organs
- Ex: tapeworms, flukes, planarian and flatworms (The Flat Planet Failed)
Phylum platyhelminthes body symmetry
Bilateral symmetry (can be split into equal right and left halves down the mid-sagittal plane) with cephalization (concentration of nervous/central organs in the brain/head)
Phylum Platyhelminthes tissue organization
Triploblastic (derived from three embryonic germ layers)
Eumetazoa
Phylum Platyhelminthes digestive system:
Gastrovascular cavity (one opening with two way digestion), except for tapeworms (they absorb food from surroundings)
Use a combination of extracellular (enzymes secreted into gastrovascular cavity, food particles breakdown) and intracellular (food particles engulfed and digested in food vacuoles) digestion
Phylum Platyhelminthes circulatory system
None- diffusion
Phylum Platyhelminthes respiratory system
None- diffusion
Phylum Platyhelminthes nervous system
Utilize two nerve cords (dense nerve bundle running along the length of invertebrates) and anterior centralized ganglia (brain)
Some planarians have eyespots
Phylum Platyhelminthes excretory system
Utilize protonephridia: bundle of flame cell that are involved in osmoregulation and filtering harmful substances from the body (function similarly to a kidney)
Phylum Platyhelminthes reproduction
Sexual reproduction: hermaphtodites (have both male and female sex organs
Asexual reproduction: regeneration
Phylum Nematoda general characteristics and examples
- Some utilize cuticles: flexible exoskeleton that prevents degradation by host digestive system
- longitudinal muscles (no circular muscles)
- Parasitic
- Not segmented
- Primarily reproduce sexually but some reproduce asexually through parthenogenesis
- Ex: round worms, hook worms and C. elegans, trichinella and ascaris
Phylum Nematoda body symmetry
Bilateral
Phylum Nematoda tissue organization
Triploblastic: derived from three embryonic germ layers
Pseudocoelomates: possessing a “pseudo” (fake) coelom —> utilized as a hydrostatic skeleton which allows for their locomotion (along with their longitudinal muscles)
Phylum Nematoda digestive system
Alimentary canal: complete, one-way digestive system from the mouth to the anus, including the esophagus, stomach and intestines
Phylum Nematoda circularity system
None- diffusion
Phylum Nematoda respiratory system
None- diffusion
Phylum Nematoda excretory system
None- diffusion
Phylum Nematoda nervous system
Utilize nerve cord and nerve ring (wraps around the esophagus)
Phylum Rotifera general characteristics and examples
- Not truly segmented
- Can reproduce sexually or parthenogenetically
- Small aquatic invertebrates organisms, mostly freshwater environments
- Draw food and water into mouth by beating motile cilia
- Feed on particular organic matter, protozoans, and dead algae
- Contribute greatly to nutrient recycling and are often used in cleaning fish tanks water
- Ex: Rotifer
Phylum Rotifera body symmetry
Bilateral
Phylum Rotifera digestive system
Alimentary canal: complete, one way digestive system from the mouth to the anus
Phylum Rotifera circulatory system
None-diffusion
Phylum Rotifera respiratory system
None- diffusion
Phylum Rotifera excretory system
Utilize protonephridia with flame cells (also use cilia to help with the filtering process)
Phylum Rotifera nervous system
Utilize a cerebral ganglia (brain) with some nerves extending through the body
Phylum Rotifera reproduction
Sexual reproduction
Asexual reproduction: parthenogenesis (virgin birth) where an underutilized egg develops into an offspring
Phylum Annelida general characteristics and examples
- The first phyla to develop segmentation
- Segmented bodies
- Coelom is divided by septa
- Longitudinal and circular muscles
- Ex: Earthworm, Leech, polychaete
Phylum Annelida body symmetry
Bilateral
Phylum Annelida tissue organization
Triploblastic
Coelomate: possessing a true coelom
Phylum Annelida digestive system
Alimentary canal: complete, one way digestive system with gizzard —> mechanical digestion of food before going to the intestines
Earthworms use crop for food storage, gizzard to grind food and intestine that contains typhlosole to increase surface area for absorption
Phylum Annelida circulatory system
(First phyla to posses a true circularly system)
Closed circulatory system: (blood always found in a vessel and never fills the body cavities) blood is pumped through vessels by the heart, multiple pairs of aortic arches and distinct arteries and veins
Phylum Annelida nervous system
Utilize ventral nerve cord and anterior ganglia (brain)
Phylum Annelida excretory system
Most have metanephridia: excretory glands for osmoregulation that make up the back bone of the excretory system. They are a series of tubes with cilia that move fluid, which then empty into coelom and eventually brought to the exterior via ducts
Phylum Annelida reproduction
Asexual: regeneration
Sexual: hermaphrodites
Phylum Annelida embryonic development
Protostome: blastopore forms the mouth
Determinant cleavage: fate of the cell is determined early on
Phylum Mollusca general characteristics and examples
- Visceral mass (mantle): thin tissue layer found within the shell and holds the bulk of organs, secrete calcium carbonate (can be used to make shells for a snail)
- Aquatic or land (terrestrial) habitats
- Hemocoel
- Ex: Clams, snails, slugs, squid, octopus, cephalopod, gastropod
Phylum Mollusca body symmetry
Bilateral
Phylum Mollusca tissue organization
Triploblastic coelomate
Phylum Mollusca digestive system
Alimentary canal
Radula: “tongue” covered in tiny teeth
Phylum Mollusca circulatory system
Open circulatory system
Blood goes to the hemocoel: space (separate from the coelom) within an organism where blood can flow freely around the internal organs
Phylum Mollusca respiratory system
Utilize gills
Phylum Mollusca nervous system
Utilize ventral nerve cords and central ganglia (brain)
Phylum Mollusca excretory system
Utilize nephridia: pair of osmoregulatory “kidneys”
Phylum Mollusca embryonic development
Protostomes: blastopore develops into the mouth
Spiral and determinant cleavage
Phylum Anthropoda general characteristics (all)
- Most diverse phylum with the highest number of different species
- three classes: class insecta, class arachnida, and class crustacea
- Arhtro- joint, poda- feet
- chitinous exoskeleton: complex carbohydrate exoskeleton outside of the body
- Segmented body