U2T7 - Keywords Flashcards
Kingdom Plantae
Division Bryophyta
Simplest group of land plants. 2 main classes - liverworts + mosses. Poorly adapted to live on land, confined to shady, damp places. Mosses anchored in substrate by rhizoids.
Rhizoids
Haploid, filamentous outgrowths of gametophyte. No role in water uptake. Don’t deeply penetrate soils + moss distribution limited to areas with water + ions close to soil surface.
Division Tracheophyta
Most primitive group to evolve true vascular system, consists of xylem (water + mineral ions) + phloem (organic nutrients). Support by turgor in cells + woody xylem vessel. 2 main groups are pteridophytes + spermatophytes.
Diploblastic
Body wall made of 2 cell layers separated by mesogloea. Little differentiation. Outer layer ectoderm, forms epidermis. Inner layer endoderm forms internal structures. Mesogloea separates ectoderm from endoderm.
Mesogloea
Jelly-like, non-cellular layer through which cells can migrate. In jellyfish, forms large part of body + acts as hydrostatic skeleton.
Polyp
Spends most time attached to substrate (rock). Tubular body, mouth + ring of tentacles on top. e.g. hydra + sea anemones.
Medusa
Free swimming bell/saucer shaped individual with tube hanging down in centre. Tube ends in mouth + tentacles line edge of bell. e.g. jellyfish.
Nematoblast
Stinging cells.
Phylum Annelida
Worm-like animals, clearly segmented aka round worms. Triploblastic. Well developed tissue differentiation. Bilaterally symmetrical + metamerically segmented, long + thin. Hydrostatic skeleton formed from segmental body cavities. Segmentation improves burrowing ability, allowing escape from predators, avoid adverse environmental conditions + exploit new environments. Certain segments may contain specialised structures (repro organs). Have blood system + simple nerve system.
Triploblastic
Ectoderm, endoderm + mesoderm.
Mesoderm
Contains coelom, within which lies well differentiated digestive + other systems. Forms bulk of body + gives rise to important structures like true muscles.
Coelomate
Having a body cavity.
Through Gut
Gut with mouth + anus, showing regional specialisation.
Phylum Arthropoda
Insects + spiders. Bilateral symmetry, fixed num of metameric segments. Most successful group as vast range of features for any ecological niche. e.g. mouth parts for chewing (locust), proboscis (green fly), large wings for flight, stings to disable prey.
Insects (Arthropods)
Have 3 segments in thorax, 10/11 in abdomen. Clearly defined body, thorax + abdomen. 3 pairs of jointed limbs attached to abdomen, through gut w/ mouth + anus. Exoskeleton made of chitin, can limit size but waterproof.
Proboscis
Elongated sucking mouthpart that is typically tubular + flexible.
Detritivores
Obtain nutrients by consuming decomposing organic matter.
Phylum Platyhelminthes
Flatworms. Flat, unsegmented, bilaterally symmetrical, possess well differentiated organ systems, triploblastic, show tissue differentiation but aceolomate, no specialised skeletal system but mesenchyme supports body, most have mouth but no anus. Usually hermaphrodites with complex repro system. Flattened dorso-ventrally.
Aceolomate
Have no coelom.
Coelom
Body cavity. Fluid filled space where organs are suspended. Blood vessels evolved from mesodermal lining of this + are within it.
Mesenchyme
Form of mesoderm.
Organ
Made up of diff tissue types which work together to carry out specific role.
Flatworms (platyhelminthes)
Have only tube-like gut/enteron so solid tissue fills space between outside + gut. Allows specialisation to occur but many cells per unit vol involved in metabolic activity so high O2 + metabolites demand. Most others have coleom. Organs crammed into body as no coleom so dense + solid. No coleom so no blood vascular system. Have more tissue than cnidarians. Single gut opening.
Phylum Chordata
Triploblastic, coelomate animals with mesoderm containing coelom, inside which is well differentiated digestive, reproductive, circulatory + excretory systems. Bilaterally symmetrical + segmented. Internal skeleton + post-anal tail at some stages in life cycle, may be reduced/lost in some species. Have notochord/spinal column. Vertebrates.
Notochord
Slender, stiff but flexible dorsal root rod running along back. Originates from mesoderm that runs along back in embryo of all chordates. Persists in primitive chordates.
Vertebral Column
In vertebrates, made of cartilage/bone.
Cartilaginous Skeleton
In cartilaginous fish, forms strong, rigid + flexible backbone.
Spinal Column
In bony fish, amphibians, reptiles, birds + mammals. Skeleton made of bone. Consists of internal jointed system of calcified bone.
Chordates Segmentation
Secondary swimming adaptation. S-shaped wiggle characteristic of swimming produced by segmental muscle blocks/myotomes which contract 1 after another in serial pattern.
Biological Symmetry
Balanced distribution of body shapes (radial, bilateral, spherical, biradial symmetry + asymmetry)
Radially Symmetric
If body of organism can be divided into identical halves in any place. Symmetry around central axis, no left or right.
Bilaterally Symmetric
If organism’s body divided by particular plane + resulting left + right sides are mirror image of each other. Generates only 2 sides as left + right.
Mosses (bryophytes)
Lack true roots, stems + leaves + don’t possess vascular tissue, support by turgor. Cells organised into structures with superficial similarity to stems + leaves, rhizoids anchor to ground. Water + minerals gained/lost over entire surface. ‘Leaves’ don’t have cuticle/stomata.
Vascular Tissue
Xylem + phloem
Pteridophytes
Ferns. Have true roots, stems + leaves (subdivided into pinnae) Have vascular tissues in roots, stems + leaves for water, ion + organic nutrient transport. Allows more growth. Support by turgor in cells + lignified xylem. Waterproof cuticle + stomata with fine control in leaves so can colonise drier areas. Rhizome runs horizontally undergrounds with leaves above ground.
Spermatophytes (angiosperms)
Flowering Plants. Variable forms, includes herbs + trees. Have true roots, stems + leaves with waterproof cuticle + stomata with fine control. Developed vascular tissue, roots can penetrate deep for water + minerals.
Pinnae
Leaflets in ferns.
Animals
Eukaryotic, multicellular organisms that don’t have cell wall. Heterotrophs. Most capable of locomotion.
Heterotrophs
Feed on organic food that they can digest internally.
Metamerically Segmented
Body divided into large num of structurally similar segments, each with own body cavity. Most segments similar in structure with own cavities.
Arachnids (arthropods)
4 pairs legs, 2 main body sections (cephalothorax + abdomen)
Cephalothorax
Head + thorax of spiders.
Segmentation
Linear series of repeating units.
Vertebrates
Vertebral/spinal column with segmented muscle blocks, skeleton consists of internal jointed system of calcified bones.
Non-vertebrate Chordates
Small group of rare animals. Bridge between invertebrates and vertebrates. Have stiff dorsal rod/notochord instead of true backbone/vertebrate column.
