Biological Diversity Flashcards
taxonomy/classicification
naming and classification of species
system of binomial nomenclature
2 part name for every organism + hierarchical classification of species into groups
broader groups (taxa): kingdom, phylum, class, order, family, genus, species
three domain classification system
- based on DNA analysis that reflects evolutionary history, phylogeny, and relationships among organisms
- reflects idea that all organisms from common ancestor
- all life organized into 3 domains: Bacteria, Archaea, Eukarya
domain Bacteria
- single-celled prokaryotes with no internal membranes
- some anaerobes, some aerobes
- bacteria play vital role in ecosystem as decomposers
- many pathogens, causing disease
- bacteria play vital role in genetic engineering
- some bacteria carry out conjugation, primitive form of sexual reproduction where individuals exchange genetic material
- thick, rigid cell wall containing peptidoglycan
- some can do photosynthesis
- no introns
- viruses placed here (bc we don’t know where else)
domain Archaea
- unicellular
- prokaryotic–no internal membranes
-
extremophiles (organisms that live in extreme environments):
1. methanogens: obtain energy by producing methane from hydrogen
2. halophiles: thrive in high salt concentration environment
3. thermophiles: thrive in very high temperatures - introns present in some genes
- no peptidoglycan
domain Eukarya
- all organisms have nucleus + internal organelles
- no peptidoglycan
- includes 4 other kingdoms: Protista, Fungi, Plantae, Animalia
Protista
four kingdoms of Eukarya
- widest variety of organisms (all eukaryotes)
- includes organisms that do not fit into fungi or plant kingdoms (e.g. seaweed)
- single + primitive multicellular organisms
- heterotrophs (e.g. amoeba, paramecium) + autotrophs (e.g. euglena)
- protozoans (e.g. amoeba, paramecium) classified by how they move
- mobility by pseudopods (amoeba), cilia (paramecium), flagella (euglena)
- some carry out conjugation
- some cause serious disease
Fungi
- heterotrophs and eukaryotic
- secrete hydrolytic enzymes outside body where extracelllular digestion occur, building blocks of nutrients absorbed into body by diffusion
- important decomposers
- chitin cell walls
Plantae
- autotrophic eukaryotes
- some have vascular tissue, some do not
Animalia
- heterotrophic, multicellular eukaryotes
- grouped in 35 phyla
- most reproduce sexually with dominant diploid stage
- small, flagellated sperm fertilizes larger, nonmotile egg (most species)
- monophyletic: all animal lineages can be traced back to common ancestor
- classified by anatomical features (homologous structures), DNA data, embryonic development
evolutionary trends in animals
- began as tiny, primitive, single-celled organism in oceans
- first multicellular eukaryotic organism evolved 1.5 billion years ago
- each phylum of animal represents evolution of new + successful body plan
- important trends include: specialization of tissues, germ layers, body symmetry, cephalization, body cavity formation
specialized cells, tissues, and organs
as larger + more complex animals evolved, specialized cells joined to form real tissues, organs, and organ systems
cell: basic unit of all forms of life
tissue: group of similar cells that perform function
organs: group of tissues that perform related functions
germ layers
- main layers that form tissues + organs
- formed early in embryonic development, result of gastrulation
- complex animals triploblastic with ectoderm, endoderm, mesoderm
primitive animals (Porifiea and Cnidarians) are diploblastic, mesoglea (middle glue) instead of mesoderm
ectoderm
outermost layer, becomes skin and nervous system, including nerve cord and brain
endoderm
innermost layer, becomes viscera (guts) or digestive system
