Bio Ch. 30 Intro to Animals

What are the 4 different categories of what animals eat?

-detritivores (dead organic material) -herbivores -carnivores (includes insectivores) -omnivores

Characteristics of animals?

-multicellular with symmetrical embryonic cell division (compare to asymmetrical division of plants) -heterotrophs (satisfy their nutritional needs by eating other organisms) -mobile for at least part of their life -have an extracellular protein matrix -neurons and "muscle" cells NOTE: although sponges & jellyfish lack muscle cells, they have the same genes for contractile proteins as other animals (the genetic sequences are homologous) -typically reproduce sexually -diploid with no alternation of generations BUT may metamorphose

What are the 4 different categories of how animals feed?

-suspension feeders (filter water or air) ex. Baleen whale -deposit feeders (eat their way through their food) ex. earthworms -fluid feeders (suck or mop up liquids) ex. butterflies -mass feeders (take chunks of food into their mouths) ex. lions

What two hypotheses explain why metamorphosis is common in animals?

1. The ability to disperse to different habitats. 2. Reduced competition (feeding efficiency). These two hypotheses are not mutually exclusive.

Themes in animal diversification: what type of body cavity?

Acoelomate, pseudocoelomate, or coelomate. Coelom = body cavity surrounded by mesoderm -allows digestive tract to be larger and longer for more complete digestion -allows more space for gonads to expand -allows more efficient movement

What are Hox genes and why are they important in the diversification of Animalia?

Cambrian "explosion" of animal body types was enabled by mutations: -Hox genes (a group of homeobox or "body plan" genes) diversified and were duplicated

Themes in animal diversification: is the body segmented?

Homeobox genes (body plan regulator genes, e.g. HOX genes) enable body segmentation: -small changes in gene expression change number, shape, & size of segments -segmentation enables specialization → diverse bodies and ways of living

What human activities are affecting these animals and how?

Human activity is driving sponges and corals to extinction. Oceans absorb more CO2 than plants, & excessive CO2 acidifies salt water: -acid dissolves calcium carbonate sponge spicules & coral exoskeletons Oceans absorb excess heat of a warming planet: -warmer water & heat waves cause "bleaching" (loss of essential symbionts) AND more severe storms Trawl/dredge fishing can dislodge sponges and break up coral reefs (which took thousand of years of growth). Chemical sunscreens, agricultural runoff, and other pollutants slow growth and introduce pathogens.

What kinds of limbs & skeletons can animals have?

Limbs -lobe-like limbs -jointed limbs -tentacles (not actually limbs) -parapodia -tube feet Skeletons Animal bodies don't require bones to move: -exoskeletons (rigid structures outside) -endoskeletons (rigid structure inside) -hydrostatic skeletons (fluid-filled tubes)

What do we stand to lose if too many of their member species go extinct?

Nearly all other species in shallow marine ecosystems depend on sponges & corals, including 1 billion humans (storm surge, fish, tourism). Ancient reefs are habitat for thousands of other species.

Approximately when & where did Kingdom Animalia first evolve?

Sponge-like microfossils appear from 635 mya. Cambrian fossils represent every living phylum of Kingdom Animalia (all aquatic).

What 2 groups of animals are known keystones in Earth's oceans?

Sponges & corals are keystone species

Themes in animal diversification: how many tissues (germ layers)?

Sponges (e.g. Grantia) are collections of cells with 0‐1 tissue layers. Diploblast animal embryos have 2 tissues layers: 1) ectoderm ("outside‐skin") 2) endoderm ("inside‐skin") Triploblast animal embryos have 3 germ layers: 1) ectoderm (skin) 2) mesoderm (muscles, organs) 3) endoderm (gut)

What distinguishes animals from their closest non-animal relatives?

Sponges' closest non‐animal relatives are choanoflagellate protists. -choanoflagellates are sessile protists (unicellular); some are colonial -sponges are multicellular, sessile animals

Themes in animal diversification: what type of nervous system?

a) Nerve net: diffuse neurons (hydra) b) CNS: clustered neurons (earthworm) Bilateral symmetry linked to evolution of head and CNS; cephalization allows for directed movement.

Themes in animal diversification: what type of body symmetry?

a) Radial symmetry (hydra) b) Bilateral symmetry (polychaete)

The Dll/Dlx genes are involved in limb formation in invertebrates and vertebrates, meaning

all animal appendages have some genetic homology