Biology Grade 12 - Unit 3: Evolution of Biological Diversity

Flashcards about the origin of life, evolution, classification, and the characteristics of different kingdoms and phyla.

When did Earth and other planets of the solar system form?

About 4.6 billion years ago

What was the likely composition of Earth's first atmosphere?

Thick with water vapor, nitrogen and its oxides, carbon dioxide, methane, ammonia, hydrogen, and little Oxygen

What kind of atmosphere did Earth have initially?

A reducing one

What conditions favored the synthesis of organic molecules essential for the origin of life?

Volcanic eruptions, lightning, extreme UV radiation, hydrothermal vents and alkaline vents along with the Earth’s reducing atmosphere

What is the age of the oldest fossils of micro-organisms, which provide direct evidence for early life on Earth?

About 3.5 billion years old

What theory explains the appearance of the first living cells through a sequence of chemical and physical processes on early Earth?

The theory of biochemical evolution

What are the four main stages by which natural selection could have produced the first cells?

1. Abiotic synthesis of small organic molecules from inorganic molecules. 2. Polymerization of small organic molecules into macromolecules. 3. Packing of macromolecules into membranes to produce protocells. 4. Nucleic acids gaining self-replicating capability, enabling inheritance

What did Haldane suggest about early oceans?

They were a solution of organic molecules called “primitive soup” in which life arose.

What is the origin of first photosynthetic organism?

Fossils of the first photosynthetic organism, today’s cyanobacteria, originated before 2.7 billion years ago.

What did the increase of photosynthetic bacteria contribute to?

The increment of the amount of atmospheric oxygen which had accelerated the origin of chloroplast.

When did the fossils of the first eukaryotic organisms appear?

About 1.8 billion years ago

When did the colonization initiate of land by fungi, plants and animals?

After about 500 million years ago

When did plants begin to differentiate as roots, stems and leaves?

Since 380 million years ago

Which group of animals was the first to colonize the land?

Arthropods (insects and spiders)

When did the earliest tetrapods form?

About 365 million years ago

When was the divergence of human lineage from other primates initiated?

6-7 million years ago

What are the Geological eons of evolution?

Hadean, Archaean, Proterozoic, Phanerozoic

What are the Geological eras of evolution?

Palaeozoic, Mesozoic, Cenozoic

When did the oldest fossils of cells (prokaryotes) appear?

Archaean eon

Which eon did diverse algae and soft-bodied invertebrate animals appear?

Proterozoic eon

In what era did marine algae become abundant and colonization of land by diverse fungi, plants, and animals occur?

Palaeozoic era

In what era did cone-bearing plants (gymnosperms) dominate; Dinosaurs evolved, radiated and origin of mammals?

Mesozoic era

What defines evolution?

A change in the genetic composition of a population from generation to generation (descent with modification) over a long period of time.

Theories of evolution

Theory of Lamarck., Darwin - Wallace theory (Theory of Natural selection), Neo Darwinism

What are Lamarck's two principles?

Use and disuse and Inheritance of acquired characteristics

What is the integration of Charles Darwin’s theory of natural selection, Mendelian genetics

Neo-Darwinism

What is called Arrangement of organisms into groups on the basis of the common characteristics?

Classification

What is the scientific study on classification, identification, nomenclature and description?

Taxonomy

What are the two methods of classification?

Artificial classification, Natural classification

Who was the first to classify organisms scientifically?

Aristotle

How did Aristotle classify plants?

According to habit: trees, shrubs and herbs, and according to lifespan: annuals, biennials and perennials.

Who classified about 6,000 plants into a hierarchical order of taxa?

Carolus Linnaeus

Who introduced a third kingdom: Protista?

Ernest Haeckel

Who introduced the five kingdom system of biological classification?

Robert H Whittaker

What are the taxonomic ranks higher than the Kingdom?

The three domains are Bacteria, Archea and Eukarya.

A microspore develops into __.

pollen grain

What is species?

A group of organisms who shares similar characteristics and has the ability to interbreed and produce viable and fertile offspring.

What is use of morphological criteria to distinguish species such as body shape and other structural features?

Morphological species concept

What is the ecological species concept?

Defines species in terms of its ecological niche and the sum of how members of the species interact with the non living and the living components of their environment

What is phylogenetic species concept?

Defines the species as the smallest group of individuals that share a common ancestor.

What is the system of nomenclature of species, which was accepted worldwide to avoid ambiguity?

Binomial system of nomenclature

What is each species has a generic name and a specific epithet?

species name or scientific name

What contains Longtitudinal, flexible rod called to located between digestive tube and nerve cord?

notochord

What is Water vascular system

network by hydraulic canals branching into tube feet which function in locomotion and feeding

Why is the use of common names for organisms, causes confusion?

More over some common names do not actually reflect the kind of organism they signify.

What are the domains in the classification system?

Bacteria, Archaea, and Eukarya

What are the kingdoms that consisting of bacteria.

Kingdom - Bacteria

What are the kingdoms that consisting of archaeabacteria.

Kingdom - Archaebacteria

What are the kingdoms that consisting of Eukarya.

Kingdom - Protista. Kingdom - Fungi, Kingdom - Plantae, Kingdom - Animalia

Key characteristics of Eukarya

They are Eukaryotic, vary in size, most of them are multicellular, Habitats are diverse, Diverse in nutrition, Mostly aerobes, Most of them exhibit sexual reproduction

Key characteristics of Protista

Most of them are unicellular. Others are colonial or multicellular, Found in freshwater, marine and damp soil, some are symbionts, Some are photoautotrophs, some are heterotrophs and some are mixotrophs

What are vascular plants grouped?

Seedless vascular plants, Seed plants

Example of seed plans

Gymnosperms, Angiosperms

Key characteristics of Domain Bacteria

They are prokaryotic, They are unicellular, colonial, filamentous, Most of them are found in size between 1μm -5μm, Well adapted to most of the “normal’ habitats , Most of them contain cell walls with peptidoglycan as major component

What is the difference of Bacterial flagellum differ from eukaryotic flagellum?

they are not covered by a plasma membrane and absence of 9+2 structure of microtubules.

What is the key characteristics of Cyanobacteria?

Prokaryotic organisms, Photosynthetic, Most are unicellular and oxygen generating and solitary, Some have the ability of fixing atmospheric nitrogen

Key Characteristics of Domain Archaea

They are prokaryotic and unicellular, They lack peptidoglycan in their cell walls which are made up of proteins and polysaccharides,The size of most of them is between 0.5-5 um, They include extreme halophiles and extreme thermophiles

Example of Non-vascular plants.

Marchantia, Pogonatum, Anthoceros

What are the Key characteristics of Kingdom Fungi

Eukaryotic, Cell walls are made up of chitin a strong but flexible polysaccharide, They are absorptive and heterotrophs, Different species live as decomposers, parasites or mutualistics, Few are unicellular, others forming multicellular filaments called hyphae, Septa can be found in hyphae

Fungi that lack septa are known as __.

coenocytic fungi

Characteric features of Kingdom Animalia

Multicellular, Heterotrophic eukaryotes, Cells of the animals are organized into tissues, Most of them reproduce by sexually, Some show radial symmetry and some others show bilateral symmetry.

What is a Key characteristics of Obelia

Majority of them are marine, except a few fresh water species. Some are macroscopic, Simple organization: diploblastic or just 2 body cell layers- an outer layers of ectoderm and inner layer of endoderm sandwitched between these two layers is a acellular layer of mesoglea, They have a simple gastrovascular cavity, They respire through the body surface. No respiratory organs are present

Key characteristics of Platyhelminthes

Commonly known as flatworms, Free living (Planaria) or parasitic (flukes and tapeworms), They are found in marine, fresh water and in damp terrestrial habitats, Body is dorsoventrally flattened, Triploblastic with all three germ layers

Key Characteristics of Nematoda

Most of them are free living in marine, few are fresh water and damp soil environments and parasitic in plants and animals, They are bilateral symmetrical. Triploblastic with pseudocoelomic, Their body forms are cylindrical with tapered ends, They do not show distinct cephalization and segmentation. The sensory papillae are found on the anterior end of the body

Key Characteristics of Annelida

They can be marine, freshwater or in damp soil, They are segmented worms with cylindrical bodies, They are Triploblastic, Coelom (true body cavity) is present for the first time, The first animals to show cephalization

Key Characteristics of Mollusca

Majority are marine. Some inhabit freshwater and land. Some are bilateral symmetrical and few are asymmetrical, They are soft bodied and non-segmented, Body is divided into three parts: muscular foot is used for locomotion; visceral mass contains most of the internal organs; mantle is to secrete the shell

Key Characteristics of Arthropoda

One of the most successful animal groups on earth with the highest number of species. They live everywhere — air, water, soil, They have segmented bodies with “jointed legs”, They have a chitinous exoskeleton (skeleton on the outside)

Key Characteristics of Echinodermata

They are exclusively marine. Triploblastic and coelomic, slow moving or sessile, Adults are penta radial symmetrical without head and segmentation, Thin epidermis covers the endoskeleton of hard calcareous plates, Water vascular system is a network by hydraulic canals branching into tube feet which function in locomotion and feeding.

Three of the key characteristics of Chordata are:

Notochord, Dorsal hollow nerve cord, Pharyngeal slits, Muscular Post anal tail, Ventral Heart

Key characteristics of Chondrichthyes

All are aquatic, Ectothermic, Skeleton composed predominantly of cartilage, Fins for locomotion and balancing, Gills for respiration. No operculum, Body is covered with placcoid scales, Reproductive tract, excretory duct and digestive tract empty into the cloaca, a common chamber that has a single opening to the outside.

Key characteristics of Osteichthyes

All are aquatic, Ectothermic, Having a skeleton composed of bones, Gills for respiration, They are covered by a bony flap called operculum, Swim bladder for control the buoyancy, Body is covered by flatten bony scales. They are ctenoid or cycloid scales

Key Characteristics of Amphibia

First animals to invade land but need water to complete life cycle, live in both water and on land, They are found only on land or fresh waters. No marine species, They are found only on land or fresh waters. No marine species

Key Characteristics of Reptilia

Mostly terrestrial some are aquatic,They are the first animal to live a complete terrestrial life,Have a skeleton composed of bones,Possess limbs for locomotion and digits

Key Characteristics of Aves

Body is covered by keratinized feathers. legs have scales, Having light and strong bony skeleton with air cavities, Fore limbs are modified with feathers for flight

Key Characteristics of Mammalia

Most of them live in terrestrial habitats. Some are aquatic, Nourish young by producing milk with mammary glands, Having a skeleton mainly composed of bones with cartilage articulating over surfaces, Body is covered with hair for insulation. Skin consists of glands, They are endothermic group of animals and most of them have high metabolic rate.