Invertebrates__Arthropods Flashcards
Q: Describe invertebrates (general characteristics)
Animals without backbones.
Invertebrates may have some type of internal or external support.
Q: Typical reproductive strategy for invertebrates
Have mass numbers of offspring all at once, maybe only once in their life
Q: Examples of invertebrates
Jellyfish, octopi, mollusks, worms, spiders, insects
Q: Relative population sizes of invertebrates vs. vertebrate species. Also arthropods.
97% of all known [animal] species are invertebrates.
Arthropods are the most diverse and numerous group of animals on earth
75% of known species are arthropods.
Largest group of arthropods is the insects (<1M species).
Q: What biome is home to the majority of invertebrates?
The majority of invertebrates are marine animals.
Q: Largest Phylum of invertebrates
Arthropods
Q: Meaning of Arthropoda
“jointed feet”
Q: Five major classes of arthropods
Arachnids, millipedes, centipedes, crustaceans, and insects.
Q: Arthropod characteristics
Bilateral symmetry
Hard exoskeleton
Segmented body
Paired, jointed appendages
Q: Exoskeleton
External skeleton that supports and protects an animal’s body.
Q: What are arthropod exoskeletons made of?
Chitin (pronounced kīt′n)
Q: Function of exoskeleton
Armored protection
Site for muscle attachment
Allows adjacent segments and joints to act as levers, thus improving locomotion
Has waxy coating which makes it impermeable to water and provides a resistance to water loss.
Jointed legs, acting like hinges, provide flexibility and allow for movement much like that in a medieval suit of armor.
Q: How do animals with exoskeletons grow?
Exoskeleton is hard and rigid, unable to expand and grow once formed.
Arthropods must molt (ecdysis) or shed their exoskeleton periodically.
Insects grow in spurts.
Molting is a time of vulnerability and danger and is one disadvantage of arthropod design as the new shell takes time to dry.
Q: Ecdysis
“ek-duh-suhs”
the molting or shedding of an outer layer of skin, as by insects, crustaceans, and snakes.
Q: Why are invertebrates small? (except some large marine organisms) How has this affected their adaptability to niches?
There is an upper limit to the efficient size of an exoskeleton.
Due to the lack of a sturdy, internal supportive structure, most invertebrates are small.
Small size allowed them to inhabit many more types of specialized niches than were available to a larger organism.
Q: Which animals were the first to come ashore from the oceans?
Arthropods
Q: Which animals were the first to fly?
Arthropods
Q: Features of arthropods that helped them as they evolved for life out of the water?
Hard exoskeleton prevented them from drying out
Evolved a way of getting oxygen without water by breathing air
Q: Key roles of arthropods, and especially insects in ecosystems
Vital role as decomposers of organic matter, recycling nutrients.
- Termites break down dead trees
- Many beetles help to decompose decaying animals, plants, and fungi
- Dung beetles (widespread): ground cleanup crew, fertilizes the soil, improves nutrient recycling and soil structure
Pollination of plants. (>80% of flowering plants depend on insects for pollination.)
Vital to soil aeration.
Major source of food for some birds, amphibians, reptiles, and mammals. (Especially insects!)
Control populations of pests, including other insects.
Q: Name some arthropods eaten by humans
Lobsters, crayfish, shrimp, chocolate covered ants
[Many, many more]
Q: Name some animal products from arthropods that are used by humans?
Honey, beeswax, silk
Q: Metamorphosis
The process of transformation from an immature form to an adult form in two or more distinct stages.
Q: Name two groups of animals that exhibit metamorphosis during their life cycle
Many invertebrate groups as well as amphibians exhibit metamorphosis during their life cycle
