Organisms and Their Environment Exam #2 Review

General Traits of an Animal

Heterotrophic, Multicellular, No cell walls, Active movement, Sexual reproduction, Embryonic development, and Cells are organized into tissues

asymmetrical

not symmetrical at all (sponges)

Radial

symmetrical in a circular pattern (cnidarians)

Parazoa

animals lacking tissue differentiation (sponges)

Eumetazoa

animals with differentiated tissues (most animals)

zygote

cell resulting from fertilization of an egg by a sperm

cleavage

very early cell division

blastula

hallow ball of cells

gastrulation

invagination of the blastula

blastopore

the hole that forms from gastrulation which will eventually form either the anus or mouth

Ectoderm

outer layer, becomes the epidermis (feathers, skin, hair)

Endoderm

inner layer, creates digestive tract

mesoderm

middle layer forms all other tissues

diploblasts

two germ layers (no mesoderm) - Cnidarians

triploblasts

three germ layers (ecto, endo, and mesoderm) - true animals other than cnidaria and porifera

Protostomes

have spiral cleavage and blastopore becomes the mouth.

Dueterostomes

have radial cleavage and blastopore becomes the anus.

Acoelomate

no body cavity

coelomate

body cavity entirely within the mesoderm

Pseudocoelmates

body cavity between mesoderm and ectoderm

Porifera

Sponges, no true tissues, specialized cells, spicule skeleton, and sessile

Characteristics for classifying animals

symmetry, tissues, body cavity, development

Types of symmetry

asymmetry, radial, bilateral

Types of body cavities

acoelomate, coelomate, pseudocoelomate

types of development

protostome or dueterostome

metazoa

all animals

Amoebocyte

sponge digestion

choanocyte

sponge water flow for feeding

Sklerocyte

sponge skeletal function

Polyp and medusa

cnidarian body plans

Cnidaria

Radial symmetry, diploblast, 2 forms: polyps and medusae, Specialized tissues, Gastrovascular cavity (one simple opening), Cnidocytes (stinging cells)

Platyhelminthes

Flatworms, Ciliated soft-bodied, Gastrovascular cavity (one opening), Bilateral symmetry & cephalization, Tissues organized into organs, Acoelomate (tapeworms)

Incomplete gut

a digestive system where there is only one opening for both food intake and waste removal

Complete Gut

a digestive system where there is a complete tract with separate openings for food intake and waste removal

Lophotrochozoa

Trochophore larvae phase, live in water, use cilia or body wall contractions to move (not appendages) - Platyhelminthes, Mollusca, Annelida

Ecdysozoa

Contains animals that molt (ecdysis) Exoskeleton - Hard cuticle that molts (includes arthropods and nemotodes)

Mollusca

trocophore larvae, complex organ systems, complete gut (mouth and anus), varying degrees of cephalization, muscular ‘foot’ for movement

Annelida

well-developed head, trochophore larvae, segmentation, divided by septa (tissue), more complex, specialized systems (e.g. digestion), complete gut (mouth and anus)

Nemotoda

round worms, pseudocoelomate, complete gut (mouth and anus), simple systems (e.g. digestive, nervous), thick, flexible cuticle molts as animal grows

Arthropoda

Super diverse! Over 1 million species, more specialized segments, appendages: jointed, specialized, hard cuticular exoskeleton that molts, more cephalization, complex behavior, complex sensory organs

Echinodermata

pentaradial symmetry (but bilateral larvae!), water vascular system, tube feet for movement, endoskeleton (but functionally similar to exoskeleton), marine ecosystems only

Chordata

notochord (semi-rigid cells, may be replaced by vertebral column), dorsal nerve cord, pharyngeal gill slits, postanal tail, a true endoskeleton

Traits that mark the transition from life in water to land

jaws, limbs, amniotic egg, and dry skin

mammal traits

Hair, Mammary glands, Endothermy (regulate internal temperature), and Placenta

Traits used for plant classification

Diplohaplontic lifecycle (sporophytes, gametophytes)*

• Apical meristem tissue in roots and shoots*

• Vascular tissue (tracheophytes)

• True leaves (euphyllis)

• Stomata and waxy cuticle to resist desiccation*

• Cell walls with support*

• Reproductive strategies (spores, seeds, cones, flowers)

Gametophyte

haploid stage of a plant (1n)

Sporophyte

diploid stage of a plant (2n)

Meristem Tissue

a specialized plant tissue composed of undifferentiated cells that have the ability to continuously divide, acting as the primary growth point of a plant, responsible for producing new cells that can develop into various specialized tissues and organs like leaves, stems, and roots

Apical Meristem

at root tip and stem for vertical “primary” growth

Lateral Meristem

secondary growth and outward layering.

Dermal Tissue

external plant tissue, has functions for protection

Ground Tissue

responsible for photosynthesis, storage, support

Vascular Tissue

conducts water and nutrients (xylem and phloem)

Cuticle

fatty cutin (non-living) layer on the outside of plants

Guard cells

surrounding the stomata

Xylem

conducts water and dissolved substances, made up of dead cells

Phloem

food-conducting (sugars), living cells and companion cells

Bryophyte

Mosses, Represent early transition from water to land, Thin cuticle reduces water loss, Gametes must still travel via water, Leaves are one cell thick, Grow close to ground, No specialized vascular (transport) tissue, Gametophyte stage dominates

Pterophyte

Ferns, Roots (collect water and nutrients from soil)*, Leaves with cuticle, stomata (increase photosynthetic area), Vascular tissues (xylem and phloem)*, Sporophyte is dominant form, Reproduction by spores, Reproduction still requires water: sperm swims to egg

Key steps in transition of plants from water to land

dominant sporophyte phase, avoid drying out (cuticle), structural support (e.g. lignin), capturing sunlight (leaves, apical meristem), dispersal of reproductive cells (seeds)

Why is the seed important?

Protects and provides food for embryo

Allows embryo to survive harsh periods

Aid in dispersal

Gymnosperms

naked seeds, includes conifers, Reproduce by seeds and cones ‘naked seeds’, Cones house small, dependent gametophyte stage, pollen (male gametophyte) in male cones, ovules (contain female gametophyte) in female cones, Pollen produces sperm, travels to ovules (produces eggs) via wind, Seeds disperse via cones, Thin, needle-like leaves, and Woody tissue for support

Angiosperms

Reproduce by flowers and seeds, Flowers house gametophytes, Broad leaves for photosynthesis, Structural support

Stamen and Anther

small off shoots at the middle of the flower, contain/produce sperm

Carpel and ovule

large center shoot of the flower containing/producing eggs, center of fruit

Diatoms

Autotrophs (primary producers)
– Unique shells made of silica
– Oil droplets help them stay afloat
– Some move by vibrating shells

Ciliates

Heterotrophs (eat other things)
- Sweep food particles into mouths with cilia
- Move with cilia

Amoebozoans

Common ancestors to fungi and animals
- Creep around with pseudopodia and eat other
organisms.

Fungi

Animal-like (share a common ancestor)
- Heterotrophic
- Body consists of long hyphae that can form mats (mycelium)
- Fungal cell walls have chitin (like arthropod exoskeletons)

Cytoplasm flows through hyphae to form mushrooms with spores.
• Spores dispersed by wind

Secretes digestive enzymes & absorbs organic molecules
• Some fungi are carnivorous