Biology Lecture 15

• symmetry of the body
• structure of the body
• segmentation of the body
• external appendages

The overall shape of the animal

division by at least one plane into similar halves

pentaradial symmetry

• Acoelomate
• pseudocoelomate
• coelomate

No body cavity

The internal organs float within the body cavity

Internal organd and coelom are lined with mesoderm tissue

• Allows animals to alter body shape
• More precise control of movement
• Not always apparent externally
• Segmentation may vary in different regions of the body

• Legs - increase precision and efficiency in mobility
• Antennae - sensory apendages
• Cilia - steering in ocean currents

Skink (lizard with legs) to a legless lizard

• Motile animals - move to find food
• Sessile animals - capture food by filter feeding or via endosymbionts

• Small organisms and molecules move through water column and air
• Animals collet these resources via filtering either passively or actively

• Eat living animals or animal tissue
• Generally prey are smaller in body size than predators but not always

Disease

An organism that lives in or on another organism (its host) and benefits by deriving nutrients at the host's expense.

An insect (e.g., the ichneumon wasp) whose larvae live as parasites that eventually kill their hosts (typically other insects)

• They eat dead stuff
• such as plant material, animals (scavengers) and dung

eat both meat and veggetables

• Larva - immature stage that is dramatically different in form than adult
• Adult
• One of these stages is specialized normally for despersal

Larval form - they serve dispersal functions

• - first they go to a snail remove reproductive area and use for next stage
• - next gets eaten by a fish
• - goes to the brain and covers it to control behavior
• - causes abnormal behavior which attracts a bird to eat it
• - uses the bird to lay eggs

• Thermal biology
• Water conservation
• Camouflage