animal kingdom 11j

General Features of Animals

All animals are multicellular eukaryotes

They are diverse in form

Invertebrates are animal species that lack a backbone

Vertebrates have a backbone (about 1% of Kingdom Animalia)

No cell walls

Active Movement (most)

Sexual Reproduction

Embryonic Development

Heterotrophs

The Simplest Animals: Phylum Porifera

Simple invertebrates

Live in aquatic environments

Classified due to their unique feeding system

Tiny pores in their outer walls draw water in. Cells in the sponge walls filter goodies from the water

Asymmetrical symmetry

One tissue layer

Ex. sponges

Sponges

Reproduce by sexual (eggs and sperm sent into water) and asexual reproduction (budding)

Phylum Cnidaria

consists of invertebrates including jellyfish, sea anemones, sea coral and hydroids.

Able to undergo extracellular digestion

All carnivores

Radial symmetry

2 tissue layers

reproduce both sexually and asexually (budding or fragmentation).

Some species can produce both eggs and sperm in the same organism (hermaphrodites).

Symmetry

Symmetrical objects have similar parts that are arranged in a similar manner

Three types of symmetry

Asymmetry – no pattern in parts (sponge)

Radial Symmetry – when a body is constructed around a central axis (starfish)

Bilateral symmetry – equivalent parts on both sides of a plane, includes a definite head end, known as cephalization (human, butterfly)

Phylum Platyhelminthes

In phylum Platyhelminthes (flatworms), they have bilateral symmetry

Invertebrates

3 tissue layers

Includes Tapeworms

Reproduce sexually – they produce both eggs and sperms, hence these organisms are known as hermaphrodites. Asexually (binary fission).

They can also be split at certain points and regenerate.

Flatworms

Have a simple body design, but do have a definite head and organs

Most species are parasitic, occurring within the bodies of many other kinds of animals

Phylum Nematoda - Hookworm

Includes nematodes, eelworms and rotifers

Have bilateral symmetry

Pseudocoelom – What seems to be a gut cavity

Nematodes mouth is equipped with piercing organs, sucking brings in food. Food enters digestive tract and is eliminated through the anus.

Mainly reproduce sexually

What is a Coelom?

the fluid-filled body cavity of an animal that contains the internal organs

Phylum Mollusca

Bilateral symmetry

Sexual reproduction

True coelomates (have a real body cavity)

Most have a radula = rough, tongue-like organ to scrape algae off rocks

Many different body plans (3 main classes 👇)

Gastropods – snails, slugs

→ Move with muscular foot

→ Mantle makes 1 hard shell

Bivalves – clams, oysters, scallops

→ 2-part hinged shell

→ Filter feeders

Cephalopods – octopuses, squids

→ No shell, move by jet propulsion using mantle

→ Smart + fast

Phylum Annelida - earthworms

Bodies are segmented

Sexual and asexual(budding or fission) reproduction

Bilateral symmetry

Coelomates

Includes: Earthworms, brittle worms

The advantage of segmentation is that segments can have different functions, such as reproduction, feeding

* when cut in specific spots- they can regenerate

Phylum Arthropoda

Includes insects, crabs, shrimp, lobsters, crayfish, water fleas

Bilateral symmetry

Coelomates

Sexual reproduction

Have jointed appendages + exoskeleton (made of chitin)

Exoskeleton functions:

Protects from predators

Prevents water loss

Provides muscle attachment points

Two main groups:

Chelicerates – no jaws (no mandibles)

→ includes spiders, mites, scorpions

Mandibulates – have mandibles (jaws)

→ includes crustaceans, insects, centipedes, millipedes

Phylum Echinodermata - seastars

include sea stars, sea urchins, sand dollars and sea cucumbers

They are deuterostomes (anus forming before the mouth) during development.

Sexual and asexual (dividing into parts) reproduction

The endoskeleton is composed of hard calcium-rich plates just beneath a delicate skin

They have pentamerous (5-way) symmetry.

All members have a water vascular system which acts like a line of suction cups along radial canals to tube feet.

Deuterostome vs Protostome

Protostome – mouth forms before anus

- less complex organism

Deuterostome – anus forms before mouth

-more complex body organization than protostomes

Phylum Chordata

Terrestrial vertebrates are included in this group

Bilateral symmetry

The major evolutionary innovation in this group is the notochord (skeletal cartilage rod for support)

Sexual reproduction

Deuterostomes

Amniotic Egg

Amphibians: first land animals, but still tied to water for reproduction and body fluids

Key adaptation: development of waterproof skin

Amniotic egg: allowed vertebrates to reproduce on land

Specialized membranes in the egg:

Gas exchange

Waste storage

Energy storage for developing embryo

Class: Mammals

Hair: traps body heat

Females produce milk to nourish offspring (from special glands)

Types of mammals:

Monotremes – lay eggs (platypus, echidna) → the only mammals that do this

Marsupials – early birth, young continue development in pouch

Placental mammals – embryo develops mostly in placenta before birth