Evolution and diversity of organisms Flashcards
Earth and the other planets of the solar system were formed
4.6 billion years ago.
Life originated on earth
3.5 billion years before
Comes from the fossils of micro-organisms
Fossils of the first photosynthetic organism, today’s cyanobacteria, originated before
2.7 billion years ago
fossils of the first eukaryotic organisms were estimated as from about
1.8 billion years ago
Fossils of the oldest known protists similar to small red algae were dated as
1.2 billion years ago
Many present day animal phyla appeared in which period
Early cambrian period
Several animal groups which include, porifera, sponges, cnidarians (Sea anemones and their relatives) and molluscs appeared in
Late Proterozoic
According to the DNA analysis, sponges evolved
700 million years ago
Ancestors of arthropods, chordates and other animal phyla originated
670 million years ago
Colonization of land by fungi, plants and animals began after about
500 million years ago
With the emergence of large trees, differentiation as
roots, stems and leaves began and diversified since
400 million years ago
first group of animals to colonize land
Arthropods (insects and spiders)
The earliest tetrapods formed about
365 million years ago
evolved from lobed-finned fish
The divergence of human lineage from other primates was initiated
6-7 million years ago
The origin of the human species took place
195,000 years ago
Origin of earth took place in which eon
Hadean eon
Origin of prokaryotes took place in which eon
Archaean eon
Origin of eukaryotes took place in which eon
Proterozoic eon
Diverse algae and soft-bodied invertebrate animals appeared in
Proterozoic eon
What were the dominant animal and plant groups during the paleozoic era
Dominant animal group was amphibians
Dominant plant group was seedless vascular plants
What were the dominant animal and plant groups during the mesozic era
Dominant animal group were reptiles including dinosours
Dominant plant group was gymnosperms
What were the dominant animal and plant groups during the cenozoic era
Dominant animal group was mammals
Dominant plant group was flowering plants
Origin of genus homo took place during
Cenozoic era
Origin of most present-day groups of insects took place during
Paleozoic era
Evolution
Evolution can be defined as a change in the genetic composition of a population from generation to generation (descent with modification) over a long period of time
Theory of Lamarck
Use and disuse
Inheritance of acquired characteristics - Organisms acquire adaptations during their lifetime according to the needs of the environment and offsprings to be better adapted for that particular environment
Observation of Charles Darwin
Population of a species vary in characteristics among their inheritance traits
Each species produces more offsprings than the environment could accommodate
Interpretations of the observations of Charles Darwin
Certain traits of a population which are capable of exhibiting qualities of better survival and reproduction can produce more offsprings
Variation of abilities in survival and reproduction can enhance the abundance of favourable characteristics among that population
first to classify organisms scientifically
Aristotle
Who classified plants according to habit. e.g. trees, shrubs and herbs, and according to lifespan e.g. annuals, biennials and perennials.
Theophrastus
Carolus Linnaeus
introduced binomial nomenclature and also classified about 6,000 plants into a hierarchical order of taxa,
His classification of flowering plants was based on the number of stamens and styles of flower.
He identified two kingdoms of organisms; plants and animals
Who introduced a third kingdom: Protista
Ernest Haeckel
Who introduced the taxon Phylum
Ernest Haeckel
Who introduced the five kingdom system of biological classification
Robert H Whittaker
Classified into Monera, Protista, Fungi, Plantae and
Animalia
Who introduced this three domain system
Carl Woese
Species
Species is a group of organisms who shares similar characteristics and has the ability to interbreed and produce viable and fertile offspring.
Branched hydrocarbons are only seen in
Domain Archea
Cells of the nervous tissue are originated from which germ layer
Ectoderm
Cells of the muscle and connective tissue are originated from which germ layer
Mesoderm
Unique features of Phylum Cnidaria
Diploblastic organization
Simple gastrovascular cavity
Presence of 2 body forms known as polyp and medusa.
Presence of nematocysts with stinging thread.
Phylum Cnidaria
Hydra, Sea anemone, Obelia, Corals and Jelly fish
Phylum Platyhelminthes
Planaria, Taenia , Fasciola
Unique features of Phylum Platyhelminthes
Protonephridia (flame bulbs)
Acelomate body
Phylum Nematoda
round worms, hook worms, pin worms
Unique features of Phylum Nematoda
Pseudocoelomic
1st complete alimentary canal with mouth and anus shown by
Phylum Nematoda
Phylum Annelida
Earthworms, Leeches and regworms.
Unique features of Phylum Annelida
Clitellum, parapodia and setae
Phylum showing 1st blood circulatory system
Annelida
Phylum showing 1st blood respiratory system
Annelida
Phylum Mollusca
Oysters, Clams, Slugs, Snails, Octupus, Squids, Chitons and tusks shells
Unique features of Phylum Mollusca
Radula, mantale, viscreral mass and ventral muscular foot
Unique features of Phylum Arthropoda
Malphigian tubules, book lungs, tracheal system of chitinous tubes, green glands and chitinous exoskeleton.
Phylum Echinodermata
sea stars, brittle stars, sea lily, feather star, sea cucumber, sea urchins and sand dollars
Unique features of Phylum Echinodermata
Penta-radial symmetry, water vascular system and tube feet.
4 basic characteristics of Phylum Chordates
- Dorsal, hollow, single nerve cord is present dorsally to the notochord.
- Longitudinal, flexible rod called the notochord is present in between the nerve cord and the digestive tract.
- Presence of slits or clefts in pairs on either side of the pharynx that opens to the outside of the body known as pharyngeal slits at least at the embryonic stage.
- Muscular tail that extends posterior to the anus present in embyonic stage.
Features of class Chondrichthyes
Skeleton predominantly composed of cartilage
Body covered by Placcoid scales
Heterocercal caudal fin
Gills without operculum
Digestive tract, reproductive tract and the excretory duct opens to the common chamber of Cloaca which has a single opening.
Features of class Osteichthyes
Skeleton composed of bones
Gills are covered by a bony flap known as the operculum
Caudal fin is homocercal
Most of them are viviparous
Swim bladder for controlled buoyancy
Body covered by flattened scales of ctenoid or cycloid
Example for limbless amphibian
Ichthyopis
Features of amphibians
1st vertebrate animals to invade land
1st animals to possess limbs
Sensitive to temperature changes. Contains a thin moist skin. No scales
Ectothermic
Contains nictating membrane (3rd eye lid) covering the eye.
Tympanic membrane is located behind the eye.
Shows external fertilization. Eggs without shells.
Features of class Reptilia
1st animals to live a complete terrestrial life
Body is covered by keratinized scales
Ectothermic
Poses lungs for aerial respiration
Features of class aves
Body is covered by keratinized feathers
Front limbs are converted to flight
Bones with air cavities, high metabolism
Endothermic
Features of class Mammalia
Nourish young by producing milk with mammary glands
Endothermic, high metabolic rate
Body is covered by fur for insulation
Differenciated teeth and a 4 chambered heart with complete double circulation
Unique features of class Mammalia
Mammary glands
Sweat glands and hair in the skin
Parthenogenesis
Parthenogenesis is a form of reproduction in which an egg can develop into an embryo without being fertilized by a sperm.
During parthenogensis haploid ovum may fuse with the polar nucleus.
The nervous system of flatworms comprises of
Pair of anterior ganglia and 2 longitudinal nerve cords cross linked by transverse nerves.
How does nervous system of vertebrates differ from invertebrates
Usually invertebrates have solid, double, ventral nerve cords while vertebrates have single, hollow, dorsal nerve cord.
What are the excretory structures present in annelids and molluscs
Nephridia
What are the sensory organs present in Nematods
Sensory Paillae
What are respiratory structures seen in marine arthropods and marine annelids respectively
Marine arthropods like crustaceans use internal gills while marine annelids use external gills.
Which molluscs lack radula
Bivalves
In which eon/era did marine algae became abundant and colonization of land by plants and animals occur
Paleozoic era of Phanerozoic eon
Hierarchical levels of taxonomy
Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
Which domain is more related to domain Eukarya
Domain Archea
Which unicellular protist contains a cell wall
Diatoms
In binomial nomenclature related species have
Same generic name and different specific epithets.
Absorptive nutrition
Food is digested outside the body using extracellular enzymes and the products of digestion is absorbed through the body surface.
Fungi lacking septa are known as
Coenozytic fungi (with many nuclei)
4 types of fungi phyla
Chitridiomycota
Zygomycota
Ascomycota
Basidiomycota
Zoospores
A zoospore is a motile asexual spore that uses a flagellum for locomotion
What is the only phylum of fungi producing flagellated reproductive cells
Chitridiomycota
phylum Zygomycota
Mucor and Rhizopus
Saprotypes
Organisms that feed on dead bodies.
Commensala
Symbiotic relationship in which 1 is benefited and the other party is not affected.
sporangia
simply a cell containing spores
Plasmogamy and Karyogamy
The main difference between plasmogamy and karyogamy is that plasmogamy is the fusion of two hyphal protoplasts while karyogamy is the fusion of two haploid nuclei in fungi
Zygosporangium
A Zygosporangium is a sturdy structure produced by plasmogamy and karyogamy. Zygosporangium is resistant to unfavorable environmental conditions.
Phylum Ascomycota
Aspergillus, Saccharomyces, Penicillium
Phylum Ascomycota- Asexual reproduction
Conidia are produced at the tip of the conidiphores which are specialized hyphae. (Exospores in clusters or chains)
Phylum Ascomycota- Sexual reproduction
Fusion of sexually differentiated gametangia takes place and produce sac like structure called asci.
Ascospores are produced within asci. Generally there are eight ascospores are produced in each ascus
Phylum Basidiomycota
Agaricus, Puffballs, Shell fungi
Phylum Basidiomycota - Dominant stage of the life cycle
Dikaryotic
Phylum Basidiomycota - Sexual reproduction
They produce fruiting bodies called basidiocarps during sexual reproduction. Produce basidia on the gills of the basidiocarp.
Produce basidiospores on basidium and exogenous.
It is believed that members of the kingdom Plantae were evolved from
chlorophytes/ green algae
Origin of land plants from ancestral green algae has occurred
470 million years ago
Origin of vascular plants has occurred
425 million years ago
Origin of extant seed plants has occurred
305 million years ago
Sporogenesis
Is the production of haploid spores by meiotic division of diploid spore mother cells.
Heterospory
Production of morphologicaly and sexually different 2 types of spores known as the microspore and the megaspore
Microspores produce the male gametophyte while the megaspore produces the female gametophyte.
Sorus
Clusture of sporangia
Sporophylls
Spore bearing leaves
Gametogenesis
Production of haploid gametes by the mitotic division of haploid gamete mother cells.
Gametangium
Reproductive organ of the gametophyte which involves in gametogenesis.
Antheridia
Male gametophyte producing sperms
Archegonia
Female gametophyte producing eggs
Antherozoids
Plant sperms
Monoecious
Bisexual
Dioecious
Unisexual
Pollens
Microspores of seed plants
Embryo sac
Female gametophyte of seed plants
Key traits of land plants lacking in green algae
Walled spores produced in sporangia
Multicellular gametangia
Apical mersitem
Dependent embryo
Liverworts, hornworts and mosses
Liverworts - phylum Hepatophyta (marchantia)
Hornworts - phylum Anthocerophyta (anthoceros)
Mosses - phylum Bryophyta (poganatum)
Vascular plants cover about
93% of the existing plant species
What are rhizoids
Primary absorptive structures found in Poganatum
Poganatum produced which type of sperms
Bi-flagellated motile sperms
pterophytes share a more recent common ancestor with
seed plants
Significant features of seedless vascular plants
Transportation through xylem and phloem
Evolution of roots
Evolutions of stems
How does xylem and phloem of seedless vascular plants differ from vascular seed plants
Xylem of seedless vascular plants lacks vessel elements while phloem of seedless vascular plants lacks seive tube elements, instead seive cells are present.
Club mosses produce which type of spore
Lycopodium
Homosporus
Spike mosses produce which type of spores
Selaginella
Heterosporus
All land plants carry out
Internal fertilization to prevent desiccation of gametes
What is the evolutionary trend seen in plants
is to reduce the gametophyte and advancment of the sporophyte
Which plant produces multi-flagellated sperms
Nephrolepis
Strobili
clusters of sporophylls
Sporophylls are spore bearing leaves
Megasporangium of Sellaginella produces how many megaspores
4
Male gametophyte of Sellaginella
Microscopic, enclosed within the microspore wall, non photosynthetic and depends on stored food.
Produces flagellated sperms.
Female gametophyte of Sellaginella
Multi-cellular, enclosed within the tough, thick covering of the megaspore and produces few rhizoids.
Significant features of seed plants
Production of seeds
Reduced gametophyte
Heterospory
Production of ovules and eggs
Production of pollens and sperms
A seed consists of
A seed consists of an embryo and endosperm. Endosperms supply food to the embryo. This endosperm is surrounded by a protective coat which is known as seed coat.
Only gymnosperms containing xylem vessel elements
Gnetophyta
Conversions after fertilization of cycads
Remaining female gametophyte becomes the endosperm
Ovule becomes the seed
Intergument becomes the seed coat
Which plants produces cilliated sperms
Cycadophyta
Female gametophyte of cycas
Ovule
Female gametophyte is produced within the megaspore
Corolla
Petals
Calyx
Sepals
Male reproductive part of the flower
Androecium composed of ring of stamens
In the anther of a stamen 4 chambers are present. These polen sacs represents the microsporangium. Pollen further devolop into polen grains.
Female reproductive part of the flower
Gynoecium composed of carpels
At the stage of the pollination there are 2 cells in a pollen grain, they are
Tube nucleus and the generative nucleus
Functional megaspore divides and forms
8 nuclei
From them the embyo sac (female gametophyte) consisting of 1 egg cell, 2 synergids, 3 antipodal cells and the central cell is produced. ( It has 2 polar nuclei at the center)
After fertilisation of anthophytes what are the transformations occuring?
Ovlue - seed
Intergument - seed coat
Egg cell - zygote - embryo - sporophyte
2 polar nuclei - triploid endosperm nucleus - endosperm tissue
Ovary - fruit
Parthenocapy
Production of fruits from flowers without fertilization.
It is naturally seen in banana and pineapple.
External water is required for fertilization of gametes in
Bryophytes, lycophytes and pterophytes
Isomorphic alternation of generations is seen in
Some chlorophytes
Plants which requires internal water for fertilization
Cycadophyta
They produce flagellated, cilliated sperms
Compare the reproductive structures of selaginella and anthophytes
Strobillus as the reproductive structure of selaginella while the reproductive structure of anthophytes is the flower.
Megasporophylls and microsporophylls of the strobilli represents the carpels and the stamens of a flower respectively.
Microsporangium reassembles the pollen sacs
Unique features of anthophytes
Double fertilization
Triploid endosperm
Flowers
Seive tube elements
Companion cells
Plants containing gametophytes whuch are dorso-ventrally flattned thalloid bodies.
Nephrolepis and Marchantia
Cucurbits
Plants like melons and pumpkin
Rodophytes and phaeophytes
Red algae and brown algae
Evidences that palnts are originated from chlorophytes
Common storage food is starch
Common cell wall components
Common chlorophyll pigments (a and d)
Chrysophyta
Golden brown algae
Diatoms
Double fertilization
Fertilization of the egg cells and 2 polar nuclei by 2 sperms simultaneously in anthophytes
Hilum of the seed originate from
Funiculus/ stalk of embryo
What are phyla of kingdom Plantae called
Divisions
Key traits of land plants lacking in green algae
Walled spores produced in sporangia
Multicellular gametangia
Dependent embryo
Apical meristem
Significant features of seed plants
Production of seeds
Reduced gametophyte
Heterospory
Production of ovules and eggs
Production of pollen and sperms
