Glossary- 17- (Evolution) Flashcards
Gametophyte
The haploid phase of the life history. Produces the male and female gametes.
Heteromorphic
Refers to algal or plant life histories in which the haploid gametophytic and diploid sporophytic phases are different (often very different) in size and structure.
Phragmoplast
The mitotic process in higher-plant organisms in which the nuclear envelope is non-persistent during division, and the mitotic spindle remains intact, keeping the daughter nuclei relatively far apart during cell-plate formation.
Phycoplast
The mitotic process in algal organisms in which the nuclear envelope is persistent throughout division, and the collapse of the mitotic spindle results in the close proximity of the daughter nuclei during cell-plate formation.
Sporophyte
The diploid phase of the life history. Meiosis takes place here within sporangia to produce haploid spores in plants that have an alternation of generations
Tracheids
The water-conducting cells of plants, secondarily thickened and dead when functioning. They link up to form conducting channels in the vascular cylinder.
Vascular System
The water- and food-conducting tissues; consists of xylem and phloem
Xylem
Water-conducting tissue consisting of tracheids and associated strengthening cells (fibres) and parenchyma
Caenozoic Era
The time of flowering plant dominance. From 65 million years ago to the present day.
Gondwana
An ancient land mass that comprised the continents of Australia, Antarctica, India, South America and Africa.
It began to break up during the Cretaceous and the southern conti8nents gradually moved in their current positions
Heterosporous
A plant that produces two types of meiotic spore. The smaller microspore gives rise to the “male-” or microgametophyte that produces sperm; the larger megaspore gives rise to the “female-” or megagametophyte that produces the egg cell.
Homosporous
A plant that produces only one type of meiotic spore. The spores germinating to produce only one type of gametophytes on which antheridia and archegonia are produced.
Mesozoic Era
Time of cycad and conifer dominance (and dinosaurs). 250-65 million years ago.
Carpel
A “female” part of a flower. It consists of a stigma (pollen receptive area) that is elevated on a style above the ovary (which contains ovules)
Endosperm
Triploid tissue resulting from the fusion of a sperm cell with the two polar nuclei of the megagametophyte. It is the food reserve for the developing embryo.
Fertilization
The fusion of sperm and egg (or polar )cells
Pollination
The transfer of pollen from anthers to the stigma
Stamen
A “male” part of a flower. It consists of an anther (pollen sac) borne on a sterile filament (stalk)
Germ layer
Layer of cells in embryo that develops into body features
Diploblastic
Two germ layers
Triploblastic
Three germ layers
Coelom
Body cavity within the mesoderm
Blastopore
Opening in the blastula during initial cell development
Protostome
Blastopore become mouth, anus either forms later or at same time as mouth
Deuterostome
Blastopore becomes anus, mouth develops later
Segmented
True segmentation is serial repetition of functional units in a body plan. Mesoderm and ectoderm are divided into segments; the endoderm is unsegmented.
Exopterygotes
Develop through series of larval stages or nymphs
Moulting = Ecdysis
Shedding the exoderm or exoskeleton between each larval or nymphal stage
Mantle
Dorsal body wall of mollusc which often forms shell
Mantle cavity
In molluscs, the space between mantle and main body where gills (or lungs in terrestrial snails) are found
Radula
Specialised mouthparts in molluscs
spicules
Spikey structures surrounding the mantle in chitons
Pedicellariae
Modified spines with claws capable of movement in echinoderms
Notochord
A stiff rod of mesoderm found next to the nerve chord in all chordate embryos (and some adults)
Detrivores
Species that eat dead and/or decaying organic matter
Tetrapod
Species with four feet or leg-like appendages
Archosaurs
Evolutionary origin of bird species
Prototheria
Group which the monotremes belong – egg laying mammals (echidna and platypus)
Metatheria
Marcupials, carry developing young in a pouch
Eutheria
Placental mammals
Gestation
Pregnancy
Digitigrade
Mammals that walk on the tips of the feet (on their toes)
Plantigrade
Mammals that walk on their entire feet right up to the heel, including primates, bears and hedgehogs
Bipedal
Walking on two legs
Ecology
The way in which organisms interact with their environment, including other organisms
Evolution
The change in inherited traits found in populations of individuals
Ecosystem
The environment, its physical properties and all the organisms and communities found there
Community
Any group of species that live in the same place and potentially (or actually) interact with each other
Population
A group of individuals of the same species
Symbiosis
When two species interact closely together in a way which is beneficial to one or both
Mutualism
When two species interact closely and both species benefit
Obligate symbiosis
Species have to live together or they will not survive
Facultative symbiosis
Species can live together but can also survive alone for at least part of their life
Commensalism
When two species interact closely and one species benefits; the other appears unharmed
Ecto- and Endoparasites
Species of parasite where at least part of the lifecycle requires the parasite to live outside (ectoparasite) or inside (endoparasite) a host
Evolutionary Arms Race
When individual evolves a trait that provides an advantage, other individuals must evolve a counter trait to survive or reproduce. Because there has been counter evolution, the first individual must further evolve to stay ahead of the survival or reproductive game. These can be likened to the biological version of weapons arms races.
Intra-specific competition
Competition between individuals in same species
Inter-specific competition
Competition between individuals in different species
