Warm-Up / EOC Prep 1.Which of the following adaptations allowed plants to reproduce more successfully in dry environments? A seedsB sapwood C root systemsD vascular tissue 2. The group of plants divided into monocots and dicots, which are different flower structures, are A angiospermsB bryophytes C conifersD gymnosperms

Agenda  Warm-up  Notes- Annelids and Insects  Annelid & Insect Worksheet  Life Cycle Drawings  Plant Booklet  Clean-Up  Cool-down

ANIMALS: ANNELIDS AND INSECTS Guided Notes 48

ANNELIDS  Annelids are segmented worms. Nearly 70% of all annelids live in the sea, and the other species are mostly land earthworms. The size of annelids can range from as small as 1 mm to as big as 3 meters.

ANNELIDS  Three large groups of annelids include marine worms, earthworms, and leeches.

ANNELIDS  Annelids are easily recognized by their segments, which are visible as a series of ring-like structures along their body. Each segment contains digestive, excretory, circulatory, and movement organs, but some segments are used for specific functions (jobs)-such as reproduction, feeding, or sensation, which means they are specialized.

ANNELIDS  The segments are separated by body walls called septa. Nutrients and other materials pass between the segments through their closed circulatory system (blood).

ANNELIDS  How do earthworms eat? They literally eat their way through the soil and consume their body weight in soil everyday. As they tunnel through the soil they ingest soil. It travels down the esophagus, into a storage organ called a crop and then passed into the gizzard. The gizzard grinds up the material and nutrients are absorbed through the intestines.

ANNELIDS  They have a simple brain called a cerebral ganglion. This brain is then connected to a nerve chord that runs along the bottom of the worm’s body. This nerve cord connects nerve centers in the segments to the brain, which allows the delivery of sensory information.

ANNELIDS  Inside each segment there is fluid that creates a hydrostatic skeleton that supports the segment. Muscles in each segment then pull against this skeleton. Alternating muscle contractions or pulls cause the worm to move.

ANNELIDS  Annelids also share another trait-setae. Setae are bristles found on the outside of their body that provide traction for crawling efficiently.

INSECTS  Insects are the largest group of organisms on Earth. There are more than 700,000 species, and many scientists believe that millions more exist but have not yet been discovered. In fact, 50% of all animal species are insects.

INSECTS  All insects share the same body plan made up of 3 sections:

INSECTS 1. Head: On the head are mandibles (jaws), specialized mouthparts, and antennae. The mandibles and mouth parts of different species are different based on what they eat.

INSECTS 2. Thorax: The wings and three pairs of jointed walking legs are attached to this middle section made up of 3 fused segments.

INSECTS 3. Abdomen: The last section which is made up of 9-11 segments.

INSECTS  Respiration: Most insects get oxygen through a network of fine tubes called trachea. Oxygen enters the body through holes called spiracles, and air passes into the trachea, which delivers oxygen to the rest of the body.

INSECTS  Excretion: Insects conserve water and eliminate waste with a system of excretory units called malpighian tubules. Malpighian tubules are fingerlike extensions from the gut that are bathed in blood. Water and small particles move through the tubules into the gut. Valuable materials are reabsorbed into the bodily tissues and the rest is excreted as waste.

INSECTS  The insect life cycle can be very complex and often several molts are required before the adult stage can be reached. The dramatic physical change that insects go through is called metamorphosis, and there are two types.

INSECTS  Complete Metamorphosis: Egg  Larva  Pupa  Adult

INSECTS  In complete metamorphosis the larva creates and lives inside a capsule called a chrysalis. This is called the pupa stage, and when it develops into an adult it leaves the capsule. This type of development is complex, but it can reduce competition within species because the larvae and adults use different habitats and food sources!

INSECTS  Incomplete metamorphosis: Egg  Nymph  Adult

INSECTS  Incomplete metamorphosis is much less complex. In this process the insect emerges from the egg into a juvenile or nymph, that looks exactly like the adult but smaller and without wings. After several molts (shedding of the exoskeleton) the nymph develops into an adult.

INSECTS  Some insects live in social communities such as bees and ants. They often live in highly organized societies of genetically related individuals and the role each member plays in the community depends on heredity, diet, hormones, and pheromones.

Leeches

Life Cycle Depictions  Draw both incomplete and complete metamorphosis life cycles.  One on each side of the notecard.  Label both with the phase names.  Underneath each, give a short description and an insect that develops with that life cycle.  Page 729 if needed.

Cool-Down 1. The cerebral ganglion serves what purpose in annelids? 2. What is the body plan that all insects share?