Plant and animal biology

Plant and Animal Biology
Prepared by: Mrs. IRISH M. SEQUIHOD – UDTOHAN, MS Bio

BIOLOGY
 Study of life
 BOTANY – study of Plants
 ZOOLOGY – study of Animals

Understanding Diversity
 The total number of living species is estimated to be between 4 million and 100
million, but only about 1.8 million species have been described. Biologists estimate
that to date they have identified less than 10% pf bacteria, about 10% of fungi,
only about 2 % of nematode (roundworm), and less than 20% of insect species.
 The variety of living organisms and the ecosystems they are part of are referred to
as biological diversity. The totality of life on Earth represents our biological
heritage, and the quality of life for all organisms depends on the health and
balance of this worldwide web life-forms.

Classifying organisms
 The scientific study of diversity of organisms and their evolutionary relationships is
called Systematics. An important aspect of Systematics is Taxonomy, the science
of naming, describing, and classifying organisms.
 In Biology, the term classification means arranging organisms into groups based
on similarities that reflect evolutionary relationships among lineages.
 Organisms are named using the Binomial System
Of the many classification systems that were developed, the one designed by Carolus
Linnaeus in the mid- 18th century has survived with some modification to the present
day. Linnaeus grouped organisms according to their similarities, mainly structural
similarities.

The Tree of Life and the Three Domains of
Life

Classifying Organisms
 Most biologists now classify organisms into the three domains. Some continue to
classify organisms into kingdoms but some systematists no longer recognize
“Kingdom Protista”. Instead, they assign protists to a number of “supergroups” that
more accurately reflect evolutionary relationships.
 Many systematists argue that the traditional hierarchical Linnaean categories are
limiting and do not fit well with recent findings. They maintain that using
kingdoms, classes, and other ranks are cumbersome and that classification using
these ranks must be frequently modified as researchers gather more data.

Classifying Organisms
 Some systematists prefer classifying organisms into Clades. A clade is defined as a
group of organisms that share characters inherited from a common ancestor. The
systematists prefer to identify clades and classify them in one of the three domains,
rather than using the traditional hierarchical system.
 Some systematists use an approach called Phylocode, in which organisms are
grouped into clades based on evolutionary relationships. A species is defined as a
segment of a population lineage. In this system, taxonomic ranks are not required.

Phylogenetic Trees
 These show hypothesized evolutionary relationships
 This graphically represent revolutionary relationships among organisms that have common ancestors.
 The type of phylogenetic tree we us in books are cladogram. Each branch in a cladogram represents a
clade, a group of organisms with a common ancestor. Each branching point, referred to as a node
represents divergence or splitting, of two or more new groups from a common ancestor. Thus, the
node represents the most recent common ancestor of each clade depicted by the branches.

How are organisms classified?
Genetics
Type of cell
Morphology
Ecological

BOTANY: Plant Biology
Adaptations of land plants include a waxy cuticle to prevent
water loss; multicellular gametangia; stomata; and for most
plants, vascular tissues containing lignin. Plants undergo
alternation of generations between multicellular
gametophyte and sporophyte generations.
Mosses and other bryophytes lack vascular tissues and do
not form true roots, stems, or leaves.
In club mosses and ferns, linin-hardened vascular tissues that
transport water and dissolved substances throughout the
plant body evolved.

Four major groups of plants exist today
 Structural and molecular data indicate that land plants
probably descended from a group of green algae called
charophytes or stoneworts.
 Plants consists of four major groups: Bryophytes, Seedless
vascular plants, and two groups of seeded vascular plants:
gymnosperms and angiosperms.

Seed Plants
 Like bryophytes and seedless vascular plants, seed plants have life cycles with an
tarnation of generations; they spend part of their lives in the multicellular diploid
sporophyte stage and a part in the multicellular haploid gametophyte stage. The
sporophyte generation is the dominant stage in seed plants, and the
gametophyte generation is significantly reduced in size and entirely dependent on
the sporophyte generation.
 Unlike the bryophytes and ferns, seed plants do not have free-living gametophytes.
Instead, the female gametophyte is attached to the nutritionally dependent on the
sporophyte generation.
 Seed plants produce ovules, in which is a megasporangium surrounded by
integuments, layers of sporophyte tissue that enclose the megasporangium.

Seed Plants
Alternation of generation in plants

Seed Plants
 Botanists divide seed plants into two groups based on whether or not ovary wall
surrounds their ovules (an ovary is a structure that contains one or more ovules).
 The two groups of seed plants are the gymnosperms and the angiosperms.
 The word gymnosperm is derived from the Greek for “naked seed”. They produce
seeds that are totally exposed or borne on the scales of cones. In other words, an ovary
wall does not surround the ovules of gymnosperms. Pine, Spruce, Fir, Hemlock, and
Gingko are examples of gymnosperms.
 The term angiosperm is derived from the Greek expression that means “seed enclosed
in a vessel or case”. Angiosperms are flowering plants that produce their seeds within a
fruit (a mature ovary). Thus, the ovules of angiosperms are protected. Flowering plants,
which is extremely divers, include corn, oaks, water lilies, cacti, apples, grasses, palms,
and buttercups.
 Both gymnosperms and angiosperms have vascular tissues: Xylem, for conducting
water and dissolved minerals (inorganic nutrients), and Phloem, for conducting
dissolved sugar.

Seed Plants
Spruce, Pine, Hemlock, Fir, and Gingko

GYMNOSPERMS
 CONIFERS – belonging to Phylum Coniferophyta, which include pines, spruces,
hemlocks, and firs, comprise most familiar group of gymnosperms. These 630
species of woody trees or shrubs produce annual additions of secondary tissues
(wood and bark); there are no herbaceous (non-woody) conifers. The wood
(secondary xylem) consists of tracheids, which are long, tapering cells with pits
through which water and dissolved minerals move from one cell to another.

GYMNOSPERMS
 CYCADS – belonging to Phylum Cycadophyta were very important during the
Triassic period, which began about 251 million years ago and is sometimes referred
to as the “Age of Cycads”. Most species are now extinct, and a few surviving cycads,
about 140 species, are tropical and subtropical without stout, trunk-like stems and
compound leaves that resemble those of palm or tree ferns.

GYMNOSPERMS
 GINKGO – belonging to Phylum Ginkgophyta have only Ginkgo biloba as the only
living species in its phylum. This native of eastern China grew in the wild in only
two locations, although people had cultivated it for its edible seeds in China and
Japan for centuries. This is the oldest genus of the extant trees. Like cycads, they
are dioecious, with separate male and female trees.

GYMNOSPERMS
 GNETOPHYTES – belonging to Phylum Gnetophyta consist of about 170 species
in three diverse and obscure genera (Gnetum, Ephedra, and Welwitschia). They
share certain features that make them unique among gymnosperms. For example,
gnetophytes have more efficient water-conducting cells, called vessel elements, in
their xylem. Flowering plans also have vessel element in their xylem, but of the
gymnosperms, only gnetophytes do. In addition, the cone clusters that some
gnetophytes produce resemble flower clusters, and certain details in their life
cycles resemble those of flowering plants. Despite the similarities, most botanist
now think that they represents evolutionary diversity in gymnosperms and are not
in a direct line to flowering plants.

GYMNOSPERMS
Ephedra, Gnetum, and Welwitschia

ANGIOSPERMS
 Flowering plants, are the most successful plants today, surpassing even
the gymnosperms in importance. They have adapted to almost every
habitat and, with at least 300,000 species, are Earth’s dominant plants.
Flowering plants come in wide variety of sizes and forms, from
herbaceous violets to massive eucalyptus trees. Some flowering plants –
tulips and roses, for example – have large, conspicuous flowers; others,
such as grasses and oaks, produce small, inconspicuous flowers.
 Flowering plants are vascular plants that reproduce sexually by forming
flowers and, following a unique double fertilization process, seeds within
fruits. The fruit protects the developing seeds and often aids in their
dispersal. Flowering plants have efficient water-conducting cells called
vessel elements in their xylem and efficient sugar-conducting cells called
sieve tube elements in their phloem.

Monocots and Eudicots
 These are two largest classes of flowering plants.
 Phylum Anthophyta is the phylum of these two.
Distinguishing Features of Monocots and Eudicots
Feature Monocots Eudicots
Flower parts Usually in threes Usually in fours or fives
Pollen grains One furrow or pore Three furrows or pores
Leaf venation Usually parallel Usually netted
Vascular bundles in stem
cross section
Usually scattered or more
complex arrangement
Arranged in a circle (ring)
Roots Fibrous root system Taproot system
Seeds Embryo with one cotyledon Embryo with two
cotyledons
Secondary growth(wood
and bark)
Absent Often present

Sexual reproduction takes place in flowers
 Flowers are reproductive shoots usually composed of four parts – sepals, petals,
stamens, and carpels – arranged in whorls (circles) on the end of a flower stalk, or
peduncle. The peduncle may terminate in a single flower or cluster of flowers
known as inflorescence. The tip of the flower stalk that bears the flower is known
as the receptacle.
 All four floral parts are important in the reproductive process, but only the stamens
(the “male” organs) and the carpels (the “female” organs) produce gametes. A
flower that has all parts is complete, whereas an incomplete flower lacks one or
more of these four parts. A flower with both stamens and carpels is perfect,
whereas an imperfect flower has stamens or carpels, but not both.

Sexual reproduction takes place in flowers

The Life cycle of Flowering plants

Adaptations of flowering plants
 Account for their success in terms of their ecological dominance and their great
number of species.
 Seed production as the primary means of reproduction and dispersal, an
adaptation shared with the gymnosperm, is clearly significant and provides a
definite advantage over seedless vascular plants.
 Most have efficient water-conducting vessel elements in their xylem, as well as
tracheids. Most flowering plants also have efficient carbohydrate-conducting sieve
tube elements in their phloem.
 The leaves of flowering plants, with their broad, expanded blades, are very efficient
at absorbing light for photosynthesis. Abscission of these leaves during cold or dry
periods reduces water loss and has enabled some flowering plants to expand into
habitats that would otherwise be too harsh for survival.
 Adaptability of the sporophyte generation in new habitats and changing
environments, e.g. cactus and water lily.

SEEDLESS NONVASCULAR PLANTS
 The mosses and other bryophytes are small non-vascular plants that lack a
specialized vascular, or conducting system to transport nutrients, water and
essential minerals (inorganic nutrients) throughout the plant body. In the absence
of such system, bryophytes rely on diffusion and osmosis to obtain needed
materials. This reliance means that they are restricted in size; if they were much
larger, some of their cells could not obtain enough necessary materials.
 They do not form seeds instead they reproduce and disperse primarily via haploid
spores.

BRYOPHYTES
 The bryophytes (from the Greek words meaning “moss plant”) consists of about 16, 000 species
of mosses, liverworts, and hornworts; bryophytes are the only living nonvascular plants. Because
they have no means for extensive internal transport of water, sugar, and essential minerals,
bryophytes are typical small. They generally require a moist environment of active growth and
reproductions, but some can tolerate dry areas.
 Moss gametophytes are differentiated into “leaves” and “stems”. Each individual plant has tiny,
hair like absorptive structures called rhizoids and an upright, stem like structure that bears leaf
like blades, each normally consisting of a single layer of undifferentiated cells except at the
midrib. Because they lack vascular tissues they do not have true roots, or leaves; the moss
structures are not homologous to roots, stems, or leaves in vascular plants. Some moss species
have water-conducting cells and sugar-conducting cells, although these cells are not
lignified or as specialized or effective as the conducting cells of vascular plants.

BRYOPHYTES
A Comparison of Major Groups of Seedless Plants
Plant Group Dominant Stage life cycle
Nonvascular;
reproduce by spores (bryophytes)
Liverworts (Hepatophyta)
Mosses (Bryophyta)
Gametophyte:thalloid or leafy plant
Gametophyt: leafy plant
Gametophyte: thalloid plant
Vascular ;
reproduce by spores
Club mosses (Lycipodiophyta)
Ferns (Pteridophyta)
Whisk ferns (Pteridophyta)
Horsetails (Pterodophyta)
Sporophyte: roots, rhisomes, erect stems, and leaves (microphylls)
Sporophyte: roots, rhizomes, and leaves (megaphylls)
Sporophyte: rhizomes and erect stems, no true or leaves
Sporophyte: roots, rhizomes, erect stems, and leaves (reduced megaphylls)

Liverwort
 Liverwort gametophytes are either thalloid or leafy
 Phylym Hepatophyta consist of about 6000 species of nonvascular plants with a
dominant gametophyte generation but the gametophytes of some liverworts are
quite different from those of mosses. Their body form is often a flattened, lobed
structure called thallus that is not differentiated into leaves, stems, or roots.

Hornwort
 Phylum Anthocerophyta are small group of about 100 species of bryophytes whose
gametophytes superficially resemble those of the thalloid liverworts. Hornworts live
in disturbed habitats such as fallow fields and roadsides.

SEEDLESS VASCULAR PLANTS
 The most important adaptation found in seedless vascular plants, though absent in
algae and bryophytes, is specialized vascular tissues, xylem and phloem – for
support and conduction. This system of conduction lets vascular plants grow larger
than bryophytes because water, minerals, and sugar are transported to all parts of
the plant. Although seedless vascular plants in temperate environments are
relatively small, tree ferns in the tropics may grow to heights of 18 m. All seedless
vascular plants have true stems with vascular tissues, and most also have true roots
and leaves.

SEEDLESS VASCULAR PLANTS
 Botanists have extensively studied the evolution of the leaf as the main
organ of photosynthesis. The two basic types of true leaves –
microphylls and megaphylls – evolved independently of each other. The
microphylls, which is usually small and has a single vascular strand,
probably evolved from small, projecting extensions of stem tissue
(enations). Only one group of living plants, the club mosses, has
microphylls. In contrast, macrophylls, probably evolved from stem
branches that gradually filled in with additional tissue (webbing) to form
most leaves as we know them today.

Plant Anatomy and Physiology
 The basic plant anatomy is composed of two Systems:
 The ROOT and the SHOOT.

 Root Modifications
 Plants have different root structures for specific purposes. There are many different types of
specialized roots, but two of the more familiar types of roots include aerial roots and
storage roots. Aerial roots grow above the ground, typically providing structural support.
Storage roots (for example, taproots and tuberous roots) are modified for food storage.
 Aerial roots are found in many different kinds of plants, offering varying functions depending
on the location of the plant. Epiphytic roots are a type of aerial root that enable a plant to
grow on another plant in a non-parasitic manner. The banyan tree begins as an epiphyte,
germinating in the branches of a host tree. Aerial prop roots develop from the branches and
eventually reach the ground, providing additional support. Over time, many roots will come
together to form what appears to be a trunk. The epiphytic roots of orchids develop a spongy
tissue to absorb moisture and nutrients from any organic material on their roots. In screwpine,
a palm-like tree that grows in sandy tropical soils, aerial roots develop to provide additional
support that help the tree remain upright in shifting sand and water conditions.

 Storage roots, such as carrots, beets, and sweet potatoes, are examples of
roots that are specially modified for storage of starch and water. They
usually grow underground as protection from plant-eating animals. Some
plants, however, such as leaf succulents and cacti, store energy in their leaves
and stems, respectively, instead of in their roots.

 Other examples of modified roots are aerating roots and haustorial roots.
Aerating roots, which rise above the ground, especially above water, are
commonly seen in mangrove forests that grow along salt water
coastlines. Haustorial roots are often seen in parasitic plants such as
mistletoe. Their roots allow the plants to absorb water and nutrients
from other plants.

 The LEAVES
 The plant leaves are lateral outgrowth of the stem which develop from the
meristematic tissues of buds. They are the part of the plant shoot which serves
as the chief food-producing organ in most vascular plants. To perform this
function more efficiently, they are arranged on the stem and oriented as to
allow maximum absorption of sunlight.
 The leaves may be considered as the most important life-giving part of the
plant body. The carbohydrate that is produced in the leaves in the process
of photosynthesis sustains animal life, both directly and indirectly. This
organic compound contains the energy which the plant obtains from the sun,
the same energy that powers animal and human life. Likewise, the oxygen that
plant leaves give off is essential to the continuing existence of animals and
other aerobic organisms.

 Functions of Leaves
1. Photosynthesis – Plants capture sunlight as the energy needed in photosynthesis in splitting the
molecules of water in the process.
2. Transpiration - Plants lose a large volume of water through the leaves in the form of vapor. The exit
of water is through the stomata and the cuticle, but stomatal transpiration is largely more
dominant than cuticular transpiration. It is estimated that the loss of water via stomata through
the process of transpiration exceeds 90 percent of the water absorbed by the roots.
3. Floral induction - The plant leaves synthesize and translocate the flower-inducing hormone called
florigen to the buds.
4. Food Storage - The leaves serve as food storage organ of the plant both temporarily and on long-
term basis. Under favorable conditions, the rate of photosynthesis may exceed that of translocation
of photosynthates toward other organs. During the daytime, sugars accumulate in the leaves and
starch is synthesized and stored in the chloroplasts. At nighttime, the starch is hydrolyzed to
glucose and respired or converted to transportable forms like sucrose.
5. Special uses - In banana, the leaf sheaths provide the physical support, oftenly called pseudostem,
to raise the leaves upward. In a few insect-eating plants such as the pitcher plant, venus fly-trap
and sundew, plant leaves are so modified to trap visiting insects, then releasing enzymes and
digesting them for their protein which is a source of nutrition. In some plants such
as Bryophyllum and Kalanchoe, the leaves are used for asexual reproduction

Types of Leaves:
1. Seed leaf
2. Foliage leaf
3. Scaly leaf
4. Bract leaf or Hypsophylls
5. Prophylls
6. Ligule
7. Floral leaf
8. Sporophylls

Anatomy of a leaf

ANIMAL BIOLOGY
 Animals are multi-cellular organisms
 Heterotrophic and are relying mainly on organic carbon and chemical
energy to convert the nutrients they get from food to energy.
 The major group of animals are classified under the Kingdom Animalia, also
known as Metazoa. This kingdom does not contain prokaryotes. All the
members of this kingdom are multicellular, eukaryotes. They are
heterotrophs, they depend on other organisms directly or indirectly for food.
Most of the animals ingest food and digest in the internal cavity. Most of the
organisms are motile which means they can move independently and
spontaneously.
 The Kingdom Animalia is primarily classified into two:
Invertebrate and Vertebrate

ANIMAL BIOLOGY
 General characteristics of the Kingdom Animalia are as follows:
Animals are eukaryotic, multicellular and heterotrophic organisms.
 They have multiple cells with mitochondria and they depend on other
organisms for food.
 Habitat - Most of the animals inhabit seas, fewer are seen in fresh water and
even fewer on land.
 There are around 9 to 10 million animal species that inhabit the earth. Only
800,000 species are identified.
 Biologists recognize 36 phyla in the animals kingdom.

ANIMAL BIOLOGY
 Size - The sizes of animals ranges from a few celled organism like the mesozoans to animals weighing many tons like the
blue whale.
 Animal bodies - Bodies of animals are made of cells organized into tissues which perform specific functions. in most
animals tissue are organized into complex organs, which form organ systems.
 Cell structure - The animal cell contains organelles like the nucleus, mitochondria, Golgi complex, ribosomes, endoplasmic
reticulum, lysosomes, vacuoles, centrioles, cytoskeleton.
 Animals are made up of many organ systems, that aids in performing specific functions that are necessary for the survival
of the organism.
 Organ systems are skeletal system, muscular system, digestive system, respiratory system, circulatory system, excretory
system, reproductive system, immune system and the endocrine system.
 Body symmetry - Most of the animals are bilaterally symmetrical, while primitive animals are asymmetrical and cnidarians
and echinoderms are radially symmetrical.
 Locomotion - Most animals have the ability to move, they show rapid movement when compared to plants and other
organisms.
 Respiration - It is a gaseous exchange of taking in oxygen and giving out carbon dioxide. This process takes place in
organs of respiration like the lungs, gills, book gills and book lungs and some animals skin is also used for respiration.

ANIMAL BIOLOGY
 General characteristics of the Kingdom Animalia are as follows:
 Digestion - Animals ingest food, and digestion takes place in the internal cavity like the digestive
system in animals, in primitive animals vacuoles are for digestion.
 Nervous system - Sensory mechanism and the coordination of the organ systems is carried on
by the nervous system. In animals the nervous system comprises of nerve ganglions, or brain,
spinal cords and nerves.
 Circulatory system - The distribution of nutrients, exchange of gases and removal of wastes takes
place in the circulatory system. This system comprises of the heart, blood vessels and the blood.
 Excretory system - Removal of wastes from kidneys.
 Skeletal system - support and protection is provided by the skeletal system.
 Reproductive system - Most animals reproduce sexually, by the fusion of haploid cells like the
eggs and the sperms.
 Glands of the endocrine system help in control and coordination of the body system.

ANIMAL BIOLOGY: Invertebrate
 Invertebrate, any animal that lacks a vertebral column, or backbone, in
contrast to the cartilaginous or bony vertebrates.
 More than 90 percent of all living animal species are invertebrates.
Worldwide in distribution, they include animals as diverse as sea stars, sea
urchins, earthworms, sponges, jellyfish, lobsters, crabs, insects, spiders, snails,
clams, and squid. Invertebrates are especially important as agricultural pests,
parasites, or agents for the transmission of parasitic infections to humans
and other vertebrates.
 Invertebrates serve as food for humans and are key elements in food chains
that support birds, fish, and many other vertebrate species.

Kingdom Animalia has approximately 36 sub-divisions known as
'phyla'. Each phyla share particular properties structurally and
functionally which together separate it from other phyla. Below
are the most common phyla classified under traditional
biological methodology.
Phylum Porifera – Show transition from unicellular to multicellular
life. They do not have tissue or organs and have less cell
specialization. They are also considered as the simplest animal
form.

 Phylum Cnidaria - Has a pretty much replaced the older term of Coelenterata;
which of both known as Radiate Animals because they both have radial or biradial
symmetry. Hydras, jellies, sea anemones, and corals are examples. They are soft-
bodied, carnivorous and have stinging tentacles arranged in circles around their
mouths. Simplest animals to have body symmetry and specialized cells.
 Phylum Platyhelminthes – They are flatworms that are mostly parasitic with a few
free living in sea water or freshwater. They have an organ system grade of
organization with bilateral symmetry body. Digestive system is incomplete. Parasitic
worms have direct absorption of soluble nutrients by cells and tissues. Respiration is
by simple diffusion of gases through body surface and no circulatory system. They
can reproduce by sexual or asexual way on gametic fusion and regeneration and
fission. Fertilization is internal and life cycle is complex involving one or more hosts.


 Phylum Nematoda - Nematodes are ubiquitous, unsegmented, acoelomate
and pseudocoelomate worms. Nematodes are probably the most abundant
multicellular animals alive today. They occur in all environments, in fresh and
sea water, on land, in polar regions and in deserts. They can be found in hot
springs, high up mountains and in the deepest oceans.
 Phylum Mollusca - an invertebrate of a large phylum that includes snails,
slugs, mussels, and octopuses. They have a soft, unsegmented body and live
in aquatic or damp habitats, and most kinds have an external calcareous
shell. The body symmetry of Mollusca and Annelida is a figure of the same
bilateral appearance when it is cut in half longitudinal.

 Phylum Annelida -The annelids are bilaterally symmetrical, triploblastic, coelomate,
invertebrate organisms. They have elongated body and are round. Some are hormonomous,
with body segments mostly similar, others are heteronomous with specialized segments.
 Phylum Arthropods -is the most numerous phylum of all living organisms, both in
number of species and in number of individuals. They have a segmented body,
jointed legs, and a tough outer covering or exoskeleton.
 Phylum Lophophorates - any of three phyla of aquatic invertebrate animals that
possess a lopophore, a fan of ciliated tentacles around the mouth. Movements of
the cilia create currents of water that carry food particles toward the mouth. The
lophophorates include the moss animals (phylum Bryozoa), lamp shells (phylum
Brachiopoda), and phoroid worms (phylum Phoronida). The phyla are no longer
thought to be closely related to each other.

 Phylum Echinoderms - Echinoderms usually inhabit shallow
coastal waters and ocean trenches organisms in this class include:
Sea stars, Brittle stars, Sand dollars, and Sea cucumbers.
Phylum Ctenophora - Nearly all of ctenophores are predators and
most are nearly transparent. Comb Jellies - Gelatinous Carnivores.
The 150 or so described species are exclusively marine and most
are planktonic.

ANIMAL BIOLOGY: Vertebrate
 The Vertebrata, or vertebrates, is a very diverse group, ranging from
lampreys to Man. It includes all craniates, except hagfishes, and are
characterized chiefly by a vertebral column, hence their name.
 The majority of the extant vertebrates are the jawed vertebrates, or
gnathostomes, but lampreys are jawless vertebrates. However, in Late
Silurian or Early Devonian times, about 420 to 400 million years ago, the
situation was reverse, and the majority of the vertebrate species were jawless
fishes (the "ostracoderms", presumably more closely related to the
gnathostomes than to lampreys). The decline of the jawless vertebrates and
the subsequent rise of the gnathostomes took place about 380 million years
ago.

 All chordates have 4 basic features that are present at some point during
their life cycle
Hollow Nerve Cord – Nerve cord in which nerves branch out at
regular intervals
Notochord – Long supporting rod that runs throughout body
Pharyngeal Pouches – Paired structures in throat
Muscular Tail – Extends beyond anus
 Only 4-5% of animals are chordates
 Examples = Fish, Amphibians, Reptiles, Birds

 Sub- phylum Urochordates –sometimes known as the
Tunicata, are commonly known as "sea squirts." The
body of an adult tunicate is quite simple, being
essentially a sack with two siphons through which water
enters and exits. Water is filtered inside the sack-shaped
body. However, many tunicates have a larva that is free-
swimming and exhibits all chordate characteristics: it has
a notochord, a dorsal nerve cord, pharyngeal slits, and
a post-anal tail. This "tadpole larva" will swim for some
time; in many tunicates, it eventually attaches to a hard
substrate, it loses its tail and ability to move, and its
nervous system largely disintegrates. Some tunicates are
entirely pelagic; known as salps, they typically have
barrel-shaped bodies and may be extremely abundant
in the open ocean.

 Sub-phylum Cephalochordata – are marine organisms. Their body is fish-like
with notochord and nerve cord persisting throughout life . They extend the
entire length of the body. The eyes, and jaws are absent. The fundamental
plan of the chordate body is seen in its most simple form in these
animals. Gonads are paired in Amphioxus and unpaired in Asymmetron.

 Sub- phylum Vertebrata or Craniata -
are well developed chordates. They
show distinct head. Notochord is
replaced by the vertebral column
completely or partially. The nerve-tubes
anterior and enlarged to form a brain.
Cranium protects the brain. Visceral
clefts called Gills perform respiration.
They are not more than seven pairs.
Heart is ventral Andes are present. They
are formed by several segments.

Muscle segments
Tail
Anus
Pharyngeal pouches
Mouth
Hollow
nerve cord
Notochord

 Class Fish (Ichthus)
 Three of the vertebrate classes are fish. The most primitive are the
Agnathans. These are jawless fishes that do not have scales. These are
lampreys and hagfishes.
 Fish that have skeletons consisting of hard rubber – like cartilage rather
than bone are members of Chondricthyes. Examples are sharks and rays.
 All of the bony fishes are members of Osteichthyes. Trout, Tilapia, Salmon,
and Parrot fish are example.
Tuna, bass, salmon, and trout are examples of Osteichthyes.

Class Fish (Ichthus)
Fish live in nearly every single aquatic habitat imaginable and
they are aquatic vertebrates characterized by fins, scales, and
gills.
Fish were the first vertebrates to evolve. They bring oxygen rich
water through gills and remove oxygen poor water through gill
slits. They have a closed circulatory system and have a single –
chambered heart.
Their swim bladder controls buoyancy and are mostly are egg
laying.
Most move by contracting opposite muscles (S Shaped).

Class Amphibians
These animals spend part of their lives under water and part on
land. Frogs, toads, and salamanders are amphibians. Many of
these species must keep their skin moist by periodically
returning to wet areas. All of them must return to water in
order to reproduce because their eggs would dry out
otherwise. They start life with gills, like fish, and later develop
lungs to breathe air.

Class Reptiles
Includes turtles, snakes, lizards, alligators, and other reptiles. All
of them have lungs to breath on land and skin that does not
need to be kept wet. They produce amniote egg which usually
has a calcium carbonate rich, leather hard shell that protects
the embryo from drying out. This is an advantage over fish and
amphibians because amniote egg can be laid on land where it
is usually safer from predators that would be in lakes, rivers,
and oceans.

Class Birds (Aves)
This includes all the birds. They also produce amniote eggs but
usually give them greater protection from predators by laying
them high off of the ground or in other relatively inaccessible
locations. In the case of both reptiles and birds, the eggs are
fertilized within the reproductive tract of females. There are
other striking similarities between their anatomies and
reproductive systems. This is not surprising because birds are
descendants of theropod dinosaurs (two-legged mostly
carnivorous dinosaurs).

Class Mammalia
 First true mammals appeared 220 million years ago
 Mammals flourished after dinosaurs became extinct – 65 million years ago
 Basic characteristics
Hair
Mammary glands – produce milk to nourish young
Breathe air
Four chambered heart
Endotherms – can generate own body heat
Internal fertilization; care for young

Animal Physiology
 The fundamental biology of all animals
 Human health and disease
 The health and disease of nonhuman animals of importance
in human affairs

Animal Physiology
The study of physiology
integrates knowledge at all
levels of organization.

Animal Physiology
Physiology’s two central questions about
how animals work.
What is the mechanism by which a
function is accomplished?
How did that mechanism come to be?

Animal Physiology
Mechanisms and adaptive significance are distinct
concepts that do not imply each other .

Animal Physiology
 Animals are structurally dynamic and have organized systems
that require energy to maintain organization.
 Both time and body size are fundamental significance in the
lives of all animals.
 They are structurally dynamic and the atoms of their bodies
are dynamic exchange with the atoms in their environments.
 Although the particular atoms exchange the overall structure
stays the same energy required.

The environment an animal occupies is often
microenvironment or microclimate

Animal Physiology
 Regulation demands more energy than conformity because
regulation represents a form of organization.
 Homeostasis – the existence of regulatory systems that
automatically make adjustments to maintain internal
constancy: negative and positive feedback.
 This mechanism will help provide material needs of cells,
removes wastes from cells, regulates physical environment of
cell and communicates among cells.

Homeostasis
 Homeostatic regulatory compoments
 Controlled systems – effectors
 Regulatory systems which acquire information, process
information, integrate information, and send commands.
 Homeeostatic regulatory variables such as setpoint (optimal
chemical or physical condition), feedback information (actual
current condition), and error signal (discrepancy between
setpoint and feedback value).

Homeostasis
Negative feedback – reduces or reverses activity of
effector and returns condition to set point.
Positive feedback – amplifies activity of effector and
self-limiting activities.
Feedforward information – changes the setpoint

Homeostasis: Thermoregulation
 Living cells cannot survive temperatures above or below fairly narrow
limits. Thermosensitivities of organisms vary and their effectors vary.
 Q10 quantifies temperature sensitivity – the ratio of physiological rate
at one temperature to the rate at 10 oC lower temperature.
 Acclimatization can alter an animal’s temperature response. These
changes that allow optimal activity under different climatic
conditions.

Homeostasis: Thermoregulation
 Metabolic compensation – maintain metabolic rate in different
seasons and accomplished with alternate enzyme systems.
 Animals are classified by how they respond to environmental
temperatures (homeotherm and poikilotherm).
 They can also be classified by they respond to environmental
temperatures and their sources of body heat: ectotherm and
endotherm.

OXYGEN
 Need for oxygen due to need for
 metabolic energy.
 Releasing energy from organic
 compounds (food) release hydrogen.
 This is combined with oxygen to form
 water.
 The suitability of an environment
 depends on availability of O2.

Osmoregulation
 Osmoregulation varies according to the environment.
 Aquatic vertebrates have adaptations to maintain the water-salt
balance of their bodies.
 Cartilaginous fishes has a total concentration of ions in their blood is
less than that in the sea water. Blood plasma is nearly isotonic to sea
water because they pump it full of urea, giving their blood the same
tonicity as sea water,
 Marine bony fishes lose water by osmosis at their gills. To counteract
this, they drink sea water almost constantly and to get rid of excess
salt, they actively transport it into the surrounding sea water at the
gills. The kidneys conserve water, and they produce a scant amount
of isotonic urine.

Osmoregulation
Freshwater Bony fishes tend to gain water by osmosis
across the gills and the body surface. As a consequence,
these fishes never drink water and actively transport salts
into the blood across the membranes of their gills.
They eliminate excess water by producing large quantities
of dilute (hypotonic) urine.

Osmoregulation
Terrestrial vertebrates have adaptations to maintain the
water-salt balance of their bodies.
Kangaroo Rat lives in the desert and fur prevents loss of
water to the hair, and during the day, it remains in a cool
burrow. Rat’s nasal passage has a highly convoluted
mucous membrane surface that captures condensed water
from exhaled air.
In birds like seagulls, salt-excreting glands located near the
eyes produce a salty solution that is excreted through the
nostrils and moves down the grooves on their beaks until it
drips off.

Osmoregulation
In marine turtles, the salt gland is modified tear (lacrimal)
gland, and in sea snakes, a salivary sublingual gland
beneath the tongue gets rid of excess salt.
If humans drink sea water, we loss more water than we
take in just ridding the body of all that salt.

Osmoregulation
The kidney is an organ of
Homeostasis. It is part of the
urinary system.
Urine made by kidneys is
conducted from the body by the
other organs in the urinary system.
In all vertebrates, except fro
placental mammals, a duct from
the kidney conducts urine to a
cloaca, a common depository for
indigestible remains, urine, and sex
cells.

Osmoregulation
Urine formation requires three steps.

Osmoregulation
The kidneys concentrate urine to maintain water-salt balance.

Osmoregulation
Hormones control the reabsorption of salt.

Acid-base balance
Lungs and kidneys maintain acid-base balance.

Animal Defense
 Some animals use these methods of defense to protect themselves:
 Comouflage
 Mimicry (Batesian or Mullerian)
 Bright coloration
 “Hair” projections

Animal Defense
Some animals use these methods of defense to protect
themselves:
Comouflage
Mimicry (Batesian or Mullerian)
Bright coloration
“Hair” projections

Animal Adaptations: High Altitudes

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